L&#39;autore corrispondente ringrazia Consiglio nazionale del governo messicano di Scienze e Tecnologie CONACYT per la fornitura di una borsa di studio.

NOTA: Le istruzioni che seguono sono per Protocollo A (figura 1). Modifiche per il protocollo B, C, e D sono elencati pure. 1. Aluminum Bar Preparazione <ol><li> Posizionare un grande pezzo (500 g - 1 kg) di commerciale lingotto di alluminio di purezza in un crogiolo. </li><li> Porre il crogiolo in un forno a 800 ° C per circa 1 ora, fino fusa. </li><li> Prendere il crogiolo dal forno e versare l&#39;alluminio fuso in uno stampo cilindrico di 50 mm di diametro, leggermente inferiore al diametro finale della camera da utilizzare per l&#39;infiltrazione (51 mm) lasciando uno spazio di circa ½ mm. </li><li> Attendere 1 ora per il bar si raffreddi. </li><li> Rimuovere la barra dallo stampo. </li><li> Utilizzando una sega a nastro, tagliare in 4 pezzi uguali dimensioni. </li><li> Sand i bordi di ogni pezzo per garantire una buona misura nello stampo infiltrazioni. </li></ol> 2. Preparazione Furnace <ol><li> Programmare il forno per raggiungere un 740 &amp; #176, plateau C per almeno 2 ore. </li><li> Impostare la velocità di riscaldamento del forno a 20 ° C / min. </li></ol> 3. preforme Preparazione NOTA: A seconda dell&#39;altezza della schiuma auspicata, variare la quantità di NaCl da utilizzare per infiltrazioni tra 100 e 300 g. <ol><li> Scegliere l&#39;infiltrazione NaCl da utilizzare, con un diametro corrispondente alla gamma di dimensioni dei pori richiesto (ad esempio un intervallo tra 1,4 mm e 1,7 mm). Il materiale può essere ottenuto da fornitori chimici in elevata purezza, o supermercato comprato sale da tavola può essere utilizzato (ad esempio materiale avrà additivi come iodio e antiagglomeranti, ma questi non fare in pratica influenza il processo in misura significativa). </li><li> Selezionare setacci di un intervallo di dimensioni adeguate e impilare su un contenitore base con la dimensione più piccola apertura nella parte inferiore. </li><li> Dal sacco di NaCl dei fornitori, richiede circa 500 g e versarlo nei setacci impilati. </li><li> Agitare i setacci, Manualmente o mediante un setacciatore, per 1 min. </li><li> Scartare il NaCl lasciato nel più ampio vaglio dimensione di apertura e il contenitore inferiore, il NaCl lasciato nel setaccio piccola apertura viene utilizzato per l&#39;infiltrazione. </li><li> Pesare la quantità di infiltrazione NaCl ottenuto. </li><li> Se l&#39;importo è insufficiente, ripetere i passaggi 3,4-3,7. NOTA: Per i protocolli B, C o D, ottenere 100 g di multa NaCl (&lt;500 micron). Questo crea uno spazio aggiuntivo nello stampo per l&#39;aria intrappolata nella preforma durante l&#39;infiltrazione nel caso l&#39;aria nella preforma non sfugge adeguatamente la camera. </li></ol> 4. Mold Preparazione <ol><li> Utilizzando carta vetrata e rotolo di carta da laboratorio, pulito il cilindro stampo (Figura 2), tenendo conto speciale per entrambi i bordi superiore e inferiore, e mantenendo lo stampo privo di impurità evidenti dalla precedente uso. </li><li> Spruzzare l&#39;interno del cilindro stampo con nitruro di boro spray aerosol, creando un rivestimento sottile stratoall&#39;interno dello stampo. NOTA: Questo è ottenuto quando il colore originale dello stampo viene sostituito da uno strato bianco dello spray; non è necessario misurare la concentrazione specifica. </li><li> Lasciate che il cilindro di stampo asciugare per almeno 5 minuti a temperatura ambiente (riscaldamento a circa 100 ° C per un massimo di 1 ora può essere applicato per ulteriori asciugatura se lo si desidera). </li><li> Utilizzando carta vetrata fine, rimuovere qualsiasi residuo di nitruro di boro dai bordi del cilindro dello stampo, per migliorare la tenuta tra il cilindro stampo e lo stampo base. NOTA: I prossimi 3 passi sono per protocolli A e B; Protocolli per C e D tagliare un solo anello di guarnizione per il coperchio. </li><li> Tagliare 2 anelli di guarnizione da 1 mm di spessore foglio di grafite (OD = 60 mm, ID = 51 mm), uno per l&#39;unione tra il bordo superiore del cilindro stampo e il coperchio dello stampo porta al sistema di valvole, l&#39;altra per l&#39;unione tra il bordo inferiore del cilindro stampo e lo stampo base. </li><li> Posizionare una delle guarnizioni nella scanalatura di base dello stampo. </li><li> Posizionare il bottom del cilindro stampo nella scanalatura con la guarnizione. </li><li> Premere leggermente con un martello sulla sommità del cilindro stampo per fissare il fondo alla scanalatura base. NOTA: Per il protocollo B, C, o D, aggiungere il seguente passo. <ol><li> Versare 100 g di multa NaCl (&lt;500 micron) nel cilindro stampo e appiattire la parte superiore con una barra di alluminio tagliato toccando la cima leggermente con il martello per garantire la multa NaCl è imballato in una alta densità. NOTA: Per Protocollo D aggiungere il seguente passo. </li><li> Tagliare 2 cerchi di Soft 2 mm di spessore Kaowool ceramica ricoprire le dimensioni del diametro dello stampo (51 mm) e metterli in cima alla multa NaCl, utilizzare la barra di alluminio tagliato e il martello per premerli contro la multa NaCl. </li></ol></li><li> Versare il NaCl da infiltrato nel cilindro stampo. NOTA: Per Protocollo D aggiungere il seguente passo. <ol><li> Attaccare lo stampo e la base di una tavola vibrante, assicurandosi cilindro stampo non si muove dalla scanalatura base. Vibrareper 1 min a 50 Hz con 0,01 m di ampiezza. </li></ol></li><li> Tenendo la parte superiore del cilindro in posizione, prendere la base e agitare leggermente finché la NaCl all&#39;interno dello stampo forma una superficie piatta in alto. </li><li> Posizionare la barra di alluminio preparato sopra della preforma NaCl. </li><li> Inserire una guarnizione di grafite nella scanalatura del coperchio dello stampo. </li><li> A mano avvitare i perni di acciaio inossidabile 4 alla base e fissarli con 4 serie di dadi in acciaio inox e rondelle sulla parte superiore della base con una chiave e posizionare il coperchio dello stampo sulla parte superiore del cilindro stampo attraverso le borchie. </li><li> Con una chiave di coppia fissato a 16 N · m, avvitare le 4 set di dadi in acciaio e rondelle sulle 4 barre filettate avvitati nella base e che si estendono attraverso il coperchio, dove vengono serrati i dadi per bloccare il coperchio dello stampo in luogo. </li><li> Fissare la parte superiore del coperchio per il sistema di valvola con la guarnizione, morsetto, bullone e dado a farfalla. </li><li> Chiudere tutte le valvole del sistema. </li><li> Aprire la valvola principale di tegli pompa a vuoto e lo stampo (valvola 3). </li><li> Accendere la pompa a vuoto finché il comparatore del sistema valvolare indica la pressione più bassa possibile. </li><li> Spegnere la pompa a vuoto. </li><li> Se la perdita di vuoto nel sistema è inferiore a una velocità di 50 Torr / sec per il primo 10 sec dopo aver spento il vuoto pompare il sigillo è sufficientemente buona per l&#39;infiltrazione. </li><li> Lasciare la valvola coperchio aperto (valvola 3) per mantenere il sistema a pressione ambiente e chiudere la valvola di pompa a vuoto (valvola 1). </li><li> Senza scollegare il sistema di valvola, posizionare lo stampo nel forno preriscaldato e attendere per 1 ora. </li></ol> 5. Infiltration <ol><li> Chiudere tutte le valvole del sistema (Figura 3). </li><li> Aprire la valvola conduce alla bombola argon (valvola 2). </li><li> Aprire la valvola principale sul serbatoio del gas argon e impostare la pressione di infiltrazione con la valvola di regolazione (per una gamma 1,4 mm a 1,7 mm di NaCl granulometria, utilizzare una pressione di 3,5 bar). NOTA: Per Protocollo B, viene usata una pressione di infiltrazione di 3 bar. Utilizzare una pressione di 1 bar per protocolli C e D. </li><li> In modo rapido, aprire la valvola coperchio (valvola a 3). </li><li> Dopo 1 minuto, togliere lo stampo dal forno e posizionarlo sopra di una superficie di raffreddamento (in questo caso un blocco di rame). NOTA: Durante il raffreddamento, la pressione nel sistema cambierà. Per i primi 5 minuti di questo processo, prestare attenzione alla pressione indicata dal regolatore e regolare torna alla pressione infiltrazioni se necessario. </li></ol> Estrazione 6. Campione <ol><li> Dopo 30 minuti, quando lo stampo è abbastanza fresco da maneggiare con i guanti resistenti al calore della luce, staccare il sistema di valvole e posizionare la base stampo su una morsa banco di lavoro. Svitare il coperchio dalla parte superiore del cilindro. </li><li> Con il coperchio leggermente toccare la parte superiore del cilindro stampo con un martello in una direzione perpendicolare alla presa della morsa per allentare il cilindro stampo dalla scanalatura base. </li><li&gt; Rimuovere la base dello stampo dalla morsa e posizionare il cilindro di muffa nella morsa. </li><li> Con il maglio toccare l&#39;alluminio rimanente sopra del campione per spingerlo fuori dal cilindro stampo. </li><li> Utilizzando una sega a nastro, tagliare la parte inferiore del campione di schiuma, eliminando l&#39;alluminio avanzo. </li><li> A seconda dell&#39;altezza di schiuma desiderata, tagliare dove desiderato, vicino alla parte superiore del campione. </li><li> Posizionare la schiuma infiltrata in un becher con acqua e una barra di agitazione magnetica su una piastra calda agitazione per sciogliere la preforma NaCl. </li><li> Impostare la temperatura della piastra calda a 60 ° C. Cambiare l&#39;acqua ogni 10 minuti fino a quando non vi è NaCl lasciato nella schiuma. NOTA: Per garantire non c&#39;è NaCl lasciato nella schiuma, cambiare l&#39;acqua di circa 10 volte. È anche possibile effettuare controlli periodici del peso campione dopo una breve fase di essiccazione. Quando questo cessa di cambiare significativamente con un&#39;ulteriore immersione, il NaCl deve essere completamente rimosso. </li><li> Infine con un elettricoaria più secca rimuovere tutta l&#39;acqua rimasta nella schiuma. Il campione schiuma è pronta. </li></ol>

<ol>
	<li>Banhart, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manufacture,+characterisation+and+application+of+cellular+metals+and+metal+foams.">Manufacture, characterisation and application of cellular metals and metal foams.</a> Progress in Materials Science. 46, 559-632 (2000).</li><li>Conde, Y., Despois, J. -. F., Goodall, R., Marmottant, A., Salvo, L., San Marchi, C., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Replication+processing+of+highly+porous+materials.">Replication processing of highly porous materials.</a> Advanced Engineering Materials. 8 (9), 795-803 (2006).</li><li>Goodall, R., Mortensen, A., Laughlin, D. E., Hono, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+24.+Porous+Metals.">Chapter 24. Porous Metals.</a> Physical Metallurgy. , 2399-2595 (2014).</li><li>Polonsky, L., Lipson, S., Markus, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lightweight+Cellular+Metal.">Lightweight Cellular Metal.</a> Modern Castings. 39, 57-71 (1961).</li><li>San Marchi, C., Mortensen, A., Degischer, H. P., Kriszt, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+2.06.+Infiltration+and+the+Replication+Process+for+Producing+Metal+Sponges.">Chapter 2.06. Infiltration and the Replication Process for Producing Metal Sponges.</a> Handbook of Cellular Metals. , 44-56 (2002).</li><li>Galliard, C., Despois, J. F., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Processing+of+NaCl+powders+of+controlled+size+and+shape+for+the+microstructural+tailoring+of+aluminium+foams.">Processing of NaCl powders of controlled size and shape for the microstructural tailoring of aluminium foams.</a> Materials Science and Engineering A. 374 (1-2), 250-262 (2004).</li><li>Despois, J. F., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Permeability+of+open-pore+microcellular+materials.">Permeability of open-pore microcellular materials.</a> Acta Materialia. 53 (5), 1381-1388 (2005).</li><li>Goodall, R., Despois, J. F., Marmottant, A., Salvo, L., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+preform+processing+on+replicated+aluminium+foam+structure+and+mechanical+properties.">The effect of preform processing on replicated aluminium foam structure and mechanical properties.</a> Scripta Materialia. 54, 2069-2073 (2006).</li><li>Goodall, R., Marmottant, A., Salvo, L., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spherical+pore+replicated+microcellular+aluminium:+Processing+and+influence+on+properties.">Spherical pore replicated microcellular aluminium: Processing and influence on properties.</a> Materials Science and Engineering A. 465 (1-2), 124-135 (2007).</li><li>Despois, J. F., Marmottant, A., Salvo, L., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+the+infiltration+pressure+on+the+structure+and+properties+of+replicated+aluminium+foams.">Influence of the infiltration pressure on the structure and properties of replicated aluminium foams.</a> Materials Science and Engineering A. 462, 68-75 (2007).</li><li>San Marchi, ., Despois, C., F, J., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uniaxial+deformation+of+open-cell+aluminium+foam:+the+role+of+internal+damage.">Uniaxial deformation of open-cell aluminium foam: the role of internal damage.</a> Acta Materialia. 52 (10), 2895-2902 (2004).</li><li>Goodall, R., Weber, L., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+electrical+conductivity+of+microcellular+metals.">The electrical conductivity of microcellular metals.</a> Journal of Applied Physics. 100, 044912 (2006).</li><li>Kadar, C., Chmelik, F., Kendvai, J., Voros, G., Rajkovits, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acoustic+emission+of+metal+foams+during+tension.">Acoustic emission of metal foams during tension.</a> Materials Science and Engineering A. 462, 316-319 (2007).</li><li>Goodall, R., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microcellular+aluminium.">Microcellular aluminium.</a> Child&#8217;s Play! Advanced Engineering Materials. 9 (11), 951-954 (2007).</li><li>Wada, T., Inoue, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication,+Thermal+Stability+and+Mechanical+Properties+of+Porous+Bulk+Glassy+Pd-Cu-Ni-P+Alloy.">Fabrication, Thermal Stability and Mechanical Properties of Porous Bulk Glassy Pd-Cu-Ni-P Alloy.</a> Materials Transactions. 44 (10), 2228-2231 (2003).</li><li>DeFouw, J. D., Dunand, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Processing+and+compressive+creep+of+cast+replicated+IN792+Ni-base+superalloy+foams.">Processing and compressive creep of cast replicated IN792 Ni-base superalloy foams.</a> Materials Science &amp; Engineering A. 558, 129-133 (2012).</li><li>Berchem, K., Mohr, U., Bleck, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlling+the+Degree+of+Pore+Opening+of+Metal+Sponges,+Prepared+by+the+Infiltration+Preparation+Method.">Controlling the Degree of Pore Opening of Metal Sponges, Prepared by the Infiltration Preparation Method.</a> Materials Science and Engineering A. 323 (1-2), 52-57 (2002).</li><li>Lu, T. J., Ong, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+closed-celled+cellular+aluminum+alloys.">Characterization of closed-celled cellular aluminum alloys.</a> J. Mater. Sci. 36, 2773-2786 (2001).</li><li>Chou, K. S., Song, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Method+for+Making+Open-cell+Aluminum+Foams+with+Soft+Ceramic+Balls.">A Novel Method for Making Open-cell Aluminum Foams with Soft Ceramic Balls.</a> Scripta Materialia. 46 (5), 379-382 (2002).</li><li>Dairon, J., Gaillard, Y., Tissier, J. C., Balloy, D., Degallaix, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parts+Containing+Open-Celled+Metal+Foam+Manufactured+by+the+Foundry+Route:+Processes,+Performances+and+Applications.">Parts Containing Open-Celled Metal Foam Manufactured by the Foundry Route: Processes, Performances and Applications.</a> Advanced Engineering Materials. 13 (11), 1066-1071 (2011).</li><li>LeMay, J. D., Hopper, R. W., Hrubesh, L. W., Pekala, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-Density+Microcellular+Materials.">Low-Density Microcellular Materials.</a> Materials Research Society Bulletin. 15 (12), 19-20 (1990).</li><li>Seliger, H., Deuther, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Die+Herstellung+von+Schaum-+und+Zellaluminium.">Die Herstellung von Schaum- und Zellaluminium.</a> Feiburger Forschungshefte. , 103-129 (1965).</li><li>Kuchek, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+of+Making+Porous+Metallic+Article.">Method of Making Porous Metallic Article.</a> US patent. , (1966).</li><li>Han, F., Cheng, H., Wang, J., Wang, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pore+combination+on+the+mechanical+properties+of+an+open+cell+aluminum+foam.">Effect of pore combination on the mechanical properties of an open cell aluminum foam.</a> Scripta Materialia. 50 (1), 13-17 (2004).</li><li>Cao, X. -. q., Wang, Z. -. h., Ma, H. -. w., Zhao, L. -. m., Yang, G. -. t. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+cell+size+on+compressive+properties+of+aluminum+foam.">Effects of cell size on compressive properties of aluminum foam.</a> Transactions of Nonferrous Metals Society of China. 16, 351-356 (2006).</li><li>Abdulla, T., Yerokhin, A., Goodall, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+plasma+electrolytic+oxidation+coating+on+the+specific+strength+of+open-cell+aluminium+foams.">Effect of plasma electrolytic oxidation coating on the specific strength of open-cell aluminium foams.</a> Materials &amp; Design. 32, 3742-3749 (2011).</li><li>San Marchi, C., Mortensen, A., Clyne, T. W., Simancik, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+Comprehensive+Response+of+Open-cell+Aluminum+Foams+with+Sub-millimeter+Pores.">Fabrication and Comprehensive Response of Open-cell Aluminum Foams with Sub-millimeter Pores.</a> Euromat99. 5, 34 (1999).</li><li>San Marchi, C., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deformation+of+open-cell+aluminium+foam.">Deformation of open-cell aluminium foam.</a> Acta Materialia. 49 (19), 3959-3969 (2001).</li><li>Goodall, R., Despois, J. F., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sintering+of+NaCl+powder:+Mechanisms+and+first+stage+kinetics.">Sintering of NaCl powder: Mechanisms and first stage kinetics.</a> Journal of the European Ceramic Society. 26 (16), 3487-3497 (2006).</li><li>Despois, J. F., Conde, Y., San Marchi, C., Mortensen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tensile+Behaviour+of+Replicated+Aluminium+Foams.">Tensile Behaviour of Replicated Aluminium Foams.</a> Advanced Engineering Materials. 6 (6), 444-447 (2004).</li><li>Zhao, Y. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stochastic+Modelling+of+Removability+of+NaCl+in+Sintering+and+Dissolution+Process+to+Produce+Al+Foams.">Stochastic Modelling of Removability of NaCl in Sintering and Dissolution Process to Produce Al Foams.</a> Journal of Porous Materials. 10 (2), 105-111 (2003).</li></ol>

The authors declare that they have no competing financial interests.

Il metodo di base qui descritto è stato usato in diverse forme di altri ricercatori. Alcune delle varianti chiave che permettono schiume di tipo diverso da creare sono discussi. Nel caratterizzare queste schiume abbiamo misurato la porosità, in quanto si tratta di una valutazione veloce e facile da fare, ma la caratterizzazione di altre caratteristiche strutturali, come la dimensione dei pori, superficie specifica o puntone spessore potrebbe essere richiesto per ottenere una piena comprensione delle caratteristiche di...

A journal reference was corrected in the publication of <a href="http://www.jove.com/video/52268">Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity</a>. Reference 21 and 22 were originally merged together as one reference. They have been separated into references 21 and 22 in the article. The reference numbers have been updated in the article to reflect this additional reference citation. It has been updated from:
<ol start="21"><li>LeMay, J.D., Hopper, R.W., Hrubesh, L.W., &#38; Pekala, R.W. Low-Density Microcellular Materials. Materials Research Society Bulletin. 15 (12), 19&#8211;20 (1990).Seliger, H., &#38; Deuther U. Die Herstellung von Schaum- und Zellaluminium. Feiburger Forschungshefte. 103&#8211;129 (1965).</li></ol>
to:
<ol start="21"><li>LeMay, J.D., Hopper, R.W., Hrubesh, L.W., &#38; Pekala, R.W. Low-Density Microcellular Materials. Materials Research Society Bulletin. 15 (12), 19&#8211;20 (1990).</li>
<li>Seliger, H., &#38; Deuther U. Die Herstellung von Schaum- und Zellaluminium. Feiburger Forschungshefte. 103&#8211;129 (1965).</li></ol>

Erratum: Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Schiume metalliche hanno attirato una grande quantità di interessi e di attività di ricerca in questi ultimi anni, come dimostra il grande corpo di lavoro citati in ampio respiro articoli di revisione, come Banhart 1, Conde et al. 2 o più recentemente Goodall e Mortensen 3. Tra i metodi utilizzati per la produzione del materiale, il processo di replica si distingue per la sua semplicità sperimentale e il grado di controllo sulla struttura finale di schiuma che può essere offerto. Occorre notare che, sebbene in letteratura tali materiali sono spesso descritti come schiume (e sono qui) in quanto non sono prodotte da bolle di gas all&#39;interno di un liquido sono più appropriatamente chiamati metalli porosi o metalli microcellulari. La prima relazione del processo di replica è stato nei primi anni del 1960 4, ed è stato ulteriormente sviluppato in diverse fasi da allora, con notevoli progressi da parte del gruppo di ricerca di Mortensen presso l&#39;Ecole Polytechnique Federale de Lausanne in Svizzera. Il processo si basa sulla colata del metallo intorno ad una preforma di particelle che definisce la forma della porosità nel materiale finale 2, 5. Dopo raffreddamento la preforma può essere rimosso mediante lisciviazione solvente o pirolisi che causa l&#39;ossidazione. Un uso popolare di questa tecnica utilizza NaCl come supporto spazio per produrre alluminio o lega di alluminio 5-10 schiume 11-14. NaCl ha diversi vantaggi come essere facilmente accessibile, non tossico e può essere rimosso dalla schiuma per dissoluzione in acqua. Avendo un punto di fusione di 801 ° C, può essere usato con i metalli che hanno un punto di fusione inferiore a questo valore, più comunemente alluminio, ma esistono anche esempi di utilizzo con materiali come bicchieri bulk metalliche, da un mix di umidificazione lega di vetro massa metallica liquido a base di palladio e NaCl granuli 15. Sostituzione del NaCl con materiali punto di fusione più elevato consente anche la produzione di schiume di alto punto di fusione dei metalli 16. Questo può includere altri materiali idrosolubili, o quelli insolubili compresi diversi tipi di sabbia. In questa forma il processo diventa più simile a colata in sabbia convenzionale per rimuovere la sabbia, getti d&#39;acqua ad alta pressione 17, 18 o forme diverse di lavaggio 19 o agitazione 20 sono obbligatori. Il processo di base 21 procede prendendo grani di NaCl e metterli in uno stampo 4, 22, 23. Il metodo di base è stato utilizzato per rendere alluminio e leghe di alluminio schiume 24-26 per una vasta gamma di indagini comportamento schiuma. Sono state introdotte misure supplementari per controllare ulteriormente la densità e per aumentare l&#39;interconnettività dei pori; questi includono la densificazione della preforma. Per densificare preforma, sinterizzazione è stato impiegato 27, 28 ed è stato utilizzato in esperimenti diversi dal 13, con il comportamento di sinterizzazioneNaCl in base alla temperatura, granulometria e densità descritto da Goodall et al. 29. Un altro metodo usato per questo scopo è isostatica a freddo (CIP) 5, 30; questa è una tecnica più veloce che può raggiungere un più ampio spettro di densità paragonabili. La procedura può anche essere eseguita allo stato solido con polvere di metallo e grani NaCl, e viene a volte chiamato sinterizzazione e Dissoluzione Processo 31. Un&#39;indagine completa dell&#39;uso della tecnica replica finora e confronto con altre tecniche è dato in Goodall e Mortensen 3. In questo lavoro si riportano in dettaglio equipaggiamento e protocolli sperimentali che sono stati utilizzati per la lavorazione di schiume metalliche con il metodo di replica, e che sono relativamente facili da implementare in un ambiente di laboratorio di ricerca. È importante riconoscere che altre varianti di un&#39;attrezzatura, con esistono diverse capacità in altre ricerche gruppi, e che, mentre l&#39;apparecchio qui presentato è adatto per elaborare il materiale, non è la sola versione o protocollo che può essere fatto funzionare. In ogni caso, una comprensione approfondita di un metodo particolare è essenziale per il successo sperimentale. I protocolli precisi utilizzati sono di seguito dettagliati. Le variazioni di protocollo (A, B, C e D) hanno piccole modifiche tra loro, principalmente destinato ad alterare la densità delle schiume prodotte. La porosità è stata calcolata misurando la densità apparente dei campioni, il loro volume e la densità di alluminio (2,7 g / cm 3). Nello sviluppare i metodi descritti per la produzione di schiuma di alluminio dalla replica, sono stati fatti tentativi per ridurre la quantità di attrezzature avanzate al più piccolo quanto possibile, in modo tale che il metodo è facile da implementare possibile. Altre variazioni che possono essere utilizzati in diverse fasi sono discussi più avanti.

<table border="0" cellpadding="0" cellspacing="0" width="1664">
	<tbody>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Name of Reagent/ Equipment</td>
			<td style="width:187px;">Company</td>
			<td style="width:429px;">Catalog Number</td>
			<td style="width:833px;">Comments/Description</td>
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		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Salt</td>
			<td style="width:187px;">Hydrosoft</td>
			<td style="width:429px;">Granular Salt 25 kg 855754</td>
			<td>http://www.travisperkins.co.uk/p/hydrosoft-granular-salt-25kg/855754/3893446</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Aluminum</td>
			<td style="width:187px;">William Rowland</td>
			<td style="width:429px;">Aluminum Ingots 99.87% pure 25 kg drum</td>
			<td>http://www.william-rowland.com/products/high-purity-metals#product-id-1</td>
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		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Crucible</td>
			<td style="width:187px;">Morgan Advance Materials</td>
			<td style="width:429px;">Syncarb Crucible</td>
			<td>http://www.morganmms.com/crucibles-foundry-products/crucibles/syncarb/</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Furnace</td>
			<td style="width:187px;">Elite Thermal Systems</td>
			<td style="width:429px;">TLCF10/27-3216CP &#38; 2116 O/T</td>
			<td>http://www.elitefurnaces.com/eng/products/furnaces/1200%20Top%20Loading%20Furnaces.php</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Bar Mold</td>
			<td style="width:187px;">The University of Sheffield</td>
			<td style="width:429px;">Custom Made</td>
			<td>Stainless Steel 304, 15 cm height, 5 cm inner diameter, 6 cm outer diameter</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Band Saw</td>
			<td style="width:187px;">Clarke</td>
			<td style="width:429px;">CBS45MD (6&#34; x 4 1/2&#34;) 370W 060710025</td>
			<td>http://www.machinemart.co.uk/shop/product/details/cbs45md-41-2in-x-6in-metal-cutting-ban</td>
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			<td style="width:429px;">Specialist wet &#38; dry sandpaper 501885</td>
			<td>http://www.wickes.co.uk/Specialist-Wet+Dry-Sandpaper-PK4/p/501885</td>
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			<td height="18" style="height:19px;width:216px;">Sieves</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:429px;">Fisherbrand test sieves 200 mm diamater</td>
			<td>http://www.fisher.co.uk/product/brand_listing.php/F/Fisherbrand/Sieve</td>
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			<td height="18" style="height:19px;width:216px;">Balance</td>
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			<td style="width:429px;">XB 6200C</td>
			<td>http://www.precisa.co.uk/precision_balances.php</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Boron Nitride</td>
			<td style="width:187px;">Kennametal</td>
			<td style="width:429px;">500 ml spray can</td>
			<td style="width:833px;">http://www.kennametal.com/content/dam/kennametal/kennametal/common/Resources/Catalogs-Literature/Advanced%20Materials%20and%20Wear%20Components/B-13-03401_ceramic_powders 
			_brochure_EN.pdf</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Infiltration Mold, Base and Lid</td>
			<td style="width:187px;">The University of Sheffield</td>
			<td style="width:429px;">Custom Made</td>
			<td>Stainless Steel 304, 15 cm height, 5.1 cm inner diameter, 6 cm outer diameter</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Cylindrical Mold</td>
			<td style="width:187px;">The University of Sheffield</td>
			<td style="width:429px;">Custom Made</td>
			<td>Low carbon steel 1020, 15 cm height, 5 cm inner diameter, 6 cm outer diameter</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Graphite Gasket</td>
			<td style="width:187px;">Gee Graphite</td>
			<td style="width:429px;">Geegraf Stainless Steel Reinforced Graphite 1 mm thick</td>
			<td>http://www.geegraphite.com/steel_reinforced.html</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Mallet</td>
			<td style="width:187px;">Thor Hammer Co. Ltd.</td>
			<td style="width:429px;">Round Solid Super Plastic Mallet</td>
			<td>http://www.thorhammer.com/Mallets/Round/</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Wrench</td>
			<td style="width:187px;">Kennedy Professional</td>
			<td style="width:429px;">13 mm Ratchet Combination Wrench KEN5822166K</td>
			<td>https://www.cromwell.co.uk/KEN5822166K</td>
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		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Nuts</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 Steel hex full nut galvanized</td>
			<td>https://www.cromwell.co.uk/CTL6400068J</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Washers</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 Form-A steel washer bzp</td>
			<td>https://www.cromwell.co.uk/CTL6451208H</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">SS Nuts</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 A2 st/st hex full nut</td>
			<td>https://www.cromwell.co.uk/CTL6423008F</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">SS Washers</td>
			<td style="width:187px;">Matlock</td>
			<td style="width:429px;">M8 A2 st/st Form-A washer</td>
			<td>https://www.cromwell.co.uk/CTL6464008H</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Stainless Steel Studding</td>
			<td style="width:187px;">Cromwell</td>
			<td style="width:429px;">M8 x 1 Mtr A2 Stainless Steel Studding QFT6397080K</td>
			<td>https://www.cromwell.co.uk/QFT6397080K</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Valves</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">C33205000 SP16K, Nitrile Diaphragm</td>
			<td>https://www.edwardsvacuum.com/Products/View.aspx?sku=C33205000</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Fitting Cross</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">C10512412 NW16 Cross Piece Aluminum</td>
			<td>https://www.edwardsvacuum.com/Products/C10512412/View.aspx</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Fitting T</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">C10512411 NW16 T-Piece Aluminum</td>
			<td>https://www.edwardsvacuum.com/Products/C10512411/View.aspx</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Vacuum Pump</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">A36310940 E2M18 200-230/380-415V,3-ph, 50Hz</td>
			<td>http://www.edwardsvacuum.com/Products/View.aspx?sku=A36310940</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Dial Gauge</td>
			<td style="width:187px;">Edwards</td>
			<td style="width:429px;">D35610000 CG16K, 0-1040mbar</td>
			<td>http://www.edwardsvacuum.com/Products/View.aspx?sku=D35610000</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Argon Gas</td>
			<td style="width:187px;">BOC</td>
			<td style="width:429px;">Pureshield Argon Gas</td>
			<td>http://www.boconline.co.uk/en/products-and-supply/industrial-gases/inert-gases/pureshield-argon/pureshield-argon.html</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Stainless Steel Hose</td>
			<td style="width:187px;">BOC</td>
			<td style="width:429px;">Stainless Steel Hose</td>
			<td>http://www.boconline.co.uk/en/products-and-supply/speciality-equipment/hoses-and-pigtails/index.html</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Regulator</td>
			<td style="width:187px;">BOC</td>
			<td style="width:429px;">HP 1500 Series Regulator</td>
			<td style="width:833px;">http://www.boconline.co.uk/en/products-and-supply/speciality-equipment/regulators/single-stage-regulators/hp1500-series/hp1500-series.html</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Copper Block</td>
			<td style="width:187px;">William Rowland</td>
			<td style="width:429px;">Copper Ingot 25 kg</td>
			<td>http://www.william-rowland.com/products/high-purity-metals#product-id-18</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Vise</td>
			<td style="width:187px;">Record</td>
			<td style="width:429px;">T84-34 H/Duty Eng Vice 4 1/2&#34; Jaws REC5658326K</td>
			<td>https://www.cromwell.co.uk/REC5658326K</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Beaker</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:429px;">11567402 - Beaker, squat form, with graduations and spout 800mL</td>
			<td style="width:833px;">https://webshop.fishersci.com/insight2_uk/getProduct.do;jsessionid=16D5812 
			D71B8CB37B475E94281E2BEA 
			5.ukhigjavappp11?productCode=11567402&#38;resultSet 
			Position=0</td>
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		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Stirring Hot Plate</td>
			<td style="width:187px;">Corning</td>
			<td style="width:429px;">Corning stirring hot plate Model 6798-420d</td>
			<td>http://www.corning.com/lifesciences/us_canada/en/technical_resources/product_guid/shp/shp.aspx</td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:216px;">Stir Bar</td>
			<td style="width:187px;">Fisher Scientific</td>
			<td style="width:429px;">11848862 - PTFE Stir bar + Ring 25x6 mm</td>
			<td style="width:833px;">https://webshop.fishersci.com/insight2_uk/getProduct.do;jsessionid=16D5812 
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			5.ukhigjavappp11?productCode=11848862&#38;resultSet 
			Position=0</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Air dryer</td>
			<td style="width:187px;">V05</td>
			<td style="width:429px;">V05 Max Air Turbo Dryer DR-120-GB</td>
			<td>http://reviews.boots.com/2111-en_gb/1120627/v05-v05-max-air-turbo-hair-dryer-dr-120-gb-reviews/reviews.htm</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Ceramic Sheet</td>
			<td style="width:187px;">Morgan Advance Materials</td>
			<td style="width:429px;">Kaowool Blanket 2 mm thick</td>
			<td>http://www.morganthermalceramics.com/downloads/datasheets?f[0]=field_type%3A84</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:216px;">Vibrating Table</td>
			<td style="width:187px;">Pevco</td>
			<td style="width:429px;">Pevco Vibrating Table 1.25m x 0.625m x 0.6m</td>
			<td>http://www.peverilmachinery.co.uk/equipment/vibrating-tables</td>
		</tr>
	</tbody>
</table>

casting protocols for the production of open cell aluminum foams by the replication technique and the effect on porosity

Schiume di metallo sono i materiali interessanti sia da una comprensione fondamentale e pratico punto di vista delle applicazioni. Usi sono stati proposti, ed in molti casi convalidato sperimentalmente, per il peso leggero o energia d&#39;urto di assorbimento strutture, come scambiatori di calore o elettrodi elevata area superficiale, come protesi al corpo, e molti altri. Sebbene siano stati compiuti grandi progressi nella comprensione delle relazioni struttura-proprietà, il gran numero di diverse tecniche di lavorazione, ciascun materiale producendo con caratteristiche e la struttura differenti, significa che la comprensione degli effetti individuali di tutti gli aspetti della struttura non è completa. Il processo di replica, in cui il metallo fuso è infiltrato tra i granuli di materiale preforma amovibile, consente un marcatamente elevato grado di controllo ed è stato utilizzato con buoni risultati per chiarire alcuni di questi rapporti. Tuttavia, il processo ha molti passi che dipendono individuale &quot;know-how&quot;, equesto documento si propone di fornire una descrizione dettagliata di tutte le fasi di una forma di realizzazione del presente metodo di lavorazione, utilizzando materiali e attrezzature che sarebbe relativamente facile da installare in un ambiente di ricerca. Lo scopo di questo protocollo e le sue varianti è quello di produrre schiume metalliche in modo efficace e semplice, dando la possibilità di adattare l&#39;esito dei campioni modificando alcuni passaggi all&#39;interno del processo. Seguendo questo, schiume di alluminio a celle aperte, con dimensione dei pori di 1-2,36 mm di diametro e 61% al 77% la porosità possono essere ottenuti.

In Figura 4 la morfologia dei grani NaCl può essere visto (angolare e sferica), per scopi illustrativi. Le schiume ottenute con protocollo A sono stati realizzati utilizzando grani di forma angolare e il resto sono stati realizzati con i grani sferici. È stato trovato che l&#39;uso di forma diversa grani NaCl ha evidenziato alcun effetto della porosità ottenuta nei campioni. Dai risultati si può determinare che i campioni a, b, e c (fornito con protocollo A), sono in med...

Watch this Scientific Journal Video about Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity at JoVE.com

Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Replication is one of the processing techniques used for the production of porous metal sponges. In this paper one implementation of the method for the production of open celled porous aluminum is shown in detail.

Casting protocolli per la produzione di cellule aperte alluminio Schiume dalla tecnica di replica e l&#39;effetto sulla porosità

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many ...

casting-protocols-for-production-open-cell-aluminum-foams-replication

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JoVE Journal

Engineering

14.4K Views.  The University of Sheffield. Replication is one of the processing techniques used for the production of porous metal sponges. In this paper one implementation of the method for the production of open celled porous aluminum is shown in detail.

Video: Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic1-5 materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials.
Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used5. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system4.
To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7.

A general strategy for the development of charge-separating semiconductor nanocrystal composites deployable for solar energy production is presented. We show that assembly of donor-acceptor nanocrystal domains in a single nanoparticle geometry gives rise to a photocatalytic function, while bulk-heterojunctions of donor-acceptor nanocrystal films can be used for photovoltaic energy conversion.

Raccolta di energia solare per mezzo di separatori di carica-nanocristalli e loro Solidi

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials ...

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Monolayer Contact Doping of Silicon Surfaces and Nanowires Using Organophosphorus Compounds

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra shallow and sharp doping profiles at the nanometer scale. In MLCD process the dopant source is a monolayer containing dopant atoms.
In this article a detailed procedure for surface doping of silicon substrate as well as silicon nanowires is demonstrated. Phosphorus dopant source was formed using tetraethyl methylenediphosphonate monolayer on a silicon substrate. This monolayer containing substrate was brought to contact with a pristine intrinsic silicon target substrate and annealed while in contact. Sheet resistance of the target substrate was measured using 4 point probe. Intrinsic silicon nanowires were synthesized by chemical vapor deposition (CVD) process using a vapor-liquid-solid (VLS) mechanism; gold nanoparticles were used as catalyst for nanowire growth. The nanowires were suspended in ethanol by mild sonication. This suspension was used to dropcast the nanowires on silicon substrate with a silicon nitride dielectric top layer. These nanowires were doped with phosphorus in similar manner as used for the intrinsic silicon wafer. Standard photolithography process was used to fabricate metal electrodes for the formation of nanowire based field effect transistor (NW-FET). The electrical properties of a representative nanowire device were measured by a semiconductor device analyzer and a probe station.

A detailed procedure for surface doping of Silicon interfaces is provided. The ultra-shallow surface doping is demonstrated by using phosphorus containing monolayers and rapid annealing process. The method can be used for doping of macroscopic area surfaces as well as nanostructures.

Monostrato Contatto doping di silicio superfici e nanofili Uso organofosforici Composti

Monolayer Contact Doping (MLCD) is a simple method for doping of surfaces and nanostructures1. MLCD results in the formation of highly controlled, ultra ...

Fast Imaging Technique to Study Drop Impact Dynamics of Non-Newtonian Fluids

In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for detailed observation, scenarios that make it challenging to observe with conventional imaging systems. One of these is the drop impact of liquids, which usually happens within one tenth of millisecond. To tackle this challenge, a fast imaging technique is introduced that combines a high-speed camera (capable of up to one million frames per second) with a macro lens with long working distance to bring the spatial resolution of the image down to 10 &#181;m/pixel. The imaging technique enables precise measurement of relevant fluid dynamic quantities, such as the flow field, the spreading distance and the splashing speed, from analysis of the recorded video. To demonstrate the capabilities of this visualization system, the impact dynamics when droplets of non-Newtonian fluids impinge on a flat hard surface are characterized. Two situations are considered: for oxidized liquid metal droplets we focus on the spreading behavior, and for densely packed suspensions we determine the onset of splashing. More generally, the combination of high temporal and spatial imaging resolution introduced here offers advantages for studying fast dynamics across a wide range of microscale phenomena.

Drop impact of non-Newtonian fluids is a complex process since different physical parameters influence the dynamics over a very short time (less than one tenth of a millisecond). A fast imaging technique is introduced in order to characterize the impact behaviors of different non-Newtonian fluids.

Scansione veloce per studiare goccia Impatto dinamica dei fluidi non newtoniani

In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for ...

Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents and hence higher efficiencies. Photon up-conversion by way of triplet-triplet annihilation (TTA-UC) is an attractive technique for using these otherwise wasted low energy photons to produce photocurrent, while not interfering with the photoanodic performance in a deleterious manner. Further to this, TTA-UC has a number of features, distinct from other reported photon up-conversion technologies, which renders it particularly suitable for coupling with DSC technology. In this work, a proven high performance TTA-UC system, comprising a palladium porphyrin sensitizer and rubrene emitter, is combined with a high performance DSC (utilizing the organic dye D149) in an integrated device. The device shows an enhanced response to sub-bandgap light over the absorption range of the TTA-UC sub-unit resulting in the highest figure of merit for up-conversion assisted DSC performance to date.

An integrated device, incorporating a dye-sensitized solar cell and triplet-triplet annihilation up-conversion unit was produced, affording enhanced light harvesting, from a wider section of the solar spectrum. Under modest irradiation levels a significantly enhanced response to low energy photons was demonstrated, yielding a record figure of merit for dye-sensitized solar cells.

L&#39;integrazione di un Triplet-tripletta Annihilation sistema Up-conversione per migliorare Dye-sensibilizzati Risposta Solar Cell a Sub-bandgap Luce

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents ...

Ambient Method for the Production of an Ionically Gated Carbon Nanotube Common Cathode in Tandem Organic Solar Cells

A method of fabricating organic photovoltaic (OPV) tandems that requires no vacuum processing is presented. These devices are comprised of two solution-processed polymeric cells connected in parallel by a transparent carbon nanotubes (CNT) interlayer. This structure includes improvements in fabrication techniques for tandem OPV devices. First the need for ambient-processed cathodes is considered. The CNT anode in the tandem device is tuned via ionic gating to become a common cathode. Ionic gating employs electric double layer charging to lower the work function of the CNT electrode. Secondly, the difficulty of sequentially stacking tandem layers by solution-processing is addressed. The devices are fabricated via solution and dry-lamination in ambient conditions with parallel processing steps. The method of fabricating the individual polymeric cells, the steps needed to laminate them together with a common CNT cathode, and then provide some representative results are described. These results demonstrate ionic gating of the CNT electrode to create a common cathode and addition of current and efficiency as a result of the lamination procedure.

A method of fabricating, in ambient conditions, organic photovoltaic tandem devices in a parallel configuration is presented. These devices feature an air-processed, semi-transparent, carbon nanotube common cathode.

Metodo ambiente per la produzione di un ionicamente Gated Nanotubi di carbonio catodo comune in celle solari tandem Organic

A method of fabricating organic photovoltaic (OPV) tandems that requires no vacuum processing is presented. These devices are comprised of two ...

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging (ECCI) in a scanning electron microscope (SEM). ECCI allows for imaging of defects and crystallographic features under specific diffraction conditions, similar to that possible via plan-view transmission electron microscopy (PV-TEM). A particular advantage of the ECCI technique is that it requires little to no sample preparation, and indeed can use large area, as-produced samples, making it a considerably higher throughput characterization method than TEM. Similar to TEM, different diffraction conditions can be obtained with ECCI by tilting and rotating the sample in the SEM. This capability enables the selective imaging of specific defects, such as misfit dislocations at the GaP/Si interface, with high contrast levels, which are determined by the standard invisibility criteria. An example application of this technique is described wherein ECCI imaging is used to determine the critical thickness for dislocation nucleation for GaP-on-Si by imaging a range of samples with various GaP epilayer thicknesses. Examples of ECCI micrographs of additional defect types, including threading dislocations and a stacking fault, are provided as demonstration of its broad, TEM-like applicability. Ultimately, the combination of TEM-like capabilities &#8211; high spatial resolution and richness of microstructural data &#8211; with the convenience and speed of SEM, position ECCI as a powerful tool for the rapid characterization of crystalline materials.

The use of electron channeling contrast imaging in a scanning electron microscope to characterize defects in III-V/Si heteroexpitaxial thin films is described. This method yields similar results to plan-view transmission electron microscopy, but in significantly less time due to lack of required sample preparation.

Electron Channeling Contrast Imaging per Rapid III-V eteroepitassiale Caratterizzazione

Misfit dislocations in heteroepitaxial layers of GaP grown on Si(001) substrates are characterized through use of electron channeling contrast imaging ...

Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

We present a protocol for using a piezoelectrically-assisted tribometer and optical profilometer to investigate the dependence of ultrasonic wear and friction reduction on linear velocity, contact pressure, and surface properties.

Esperimenti su ultrasuoni lubrificazione Utilizzando un tribometro piezoelettrico-assistita e Profilometro ottico

Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at ...

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 &#956;m from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,&#945;&#947;)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

We illustrate the application of 1H(15N,&#945;&#947;)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.

La quantificazione delle concentrazioni di idrogeno in superficie e di interfaccia Livelli e materiale sfuso attraverso profili di profondità con l&#39;analisi reazione nucleare

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and ...

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling immensely. However, in soft electronics, in which organic semiconductors play a critical role, the devices will be bent or folded repeatedly. The effect of bending on the crystal packing and thus the charge transport is crucial to the performance of the device. In this manuscript, we describe the protocol to bend a single crystal of 5,7,12,16-tetrachloro-6,13-diazapentacene (TCDAP) in the field-effect transistor configuration and to obtain reproducible I-V characteristics upon bending the crystal. The results show that bending a field-effect transistor prepared on a flexible substrate results in nearly reversible yet opposite trends in charge mobility, depending on the bending direction. The mobility increases when the device is bent toward the top gate/dielectric layer (upward, compressive state) and decreases when bent toward the crystal/substrate side (downward, tensile state). The effect of bending curvature was also observed, with greater mobility change resulting from higher bending curvature. It is suggested that the intermolecular &#960;-&#960; distance changes upon bending, thereby influencing the electronic coupling and the subsequent carrier transport ability.

This manuscript describes the bending process of an organic single crystal-based field-effect transistor to maintain a functioning device for electronic property measurement. The results suggest that bending causes changes in the molecular spacing in the crystal and thus in the charge hopping rate, which is important in flexible electronics.

Effetto di piegare sulle caratteristiche elettriche di transistor ad effetto di campo basati su cristallo Flexible Organic singolo

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling ...

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional component that should have high electrical conductivity, high mechanical properties, and high productivity.
In this regard, a carbon fiber/epoxy resin composite can be an ideal material to replace the conventional graphite bipolar plate, which often leads to the catastrophic failure of the entire system because of its inherent brittleness. Though the carbon/epoxy composite has high mechanical properties and is easy to manufacture, the electrical conductivity in the through-thickness direction is poor because of the resin-rich layer that forms on its surface. Therefore, an expanded graphite coating was adopted to solve the electrical conductivity issue. However, the expanded graphite coating not only increases the manufacturing costs but also has poor mechanical properties.
In this study, a method to expose fibers on the composite surface is demonstrated. There are currently many methods that can expose fibers by surface treatment after the fabrication of the composite. This new method, however, does not require surface treatment because the fibers are exposed during the manufacture of the composite. By exposing bare carbon fibers on the surface, the electrical conductivity and mechanical strength of the composite are increased drastically.

A protocol to expose bare fibers on the composite surface by eliminating resin rich area is presented. The fibers are exposed during fabrication of the composites, not by the post surface treatment. The exposed carbon composites exhibit high electrical conductivity in the through-thickness direction and high mechanical property.

Implementazione sperimentale di un nuovo metodo di fabbricazione compositi: esponendo fibre nude sulla superficie composita dal metodo strato morbido

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...