Este trabalho foi apoiado pela Floresta Departamento Wake Chemistry and the Wake Centro Florestal de Energia, Meio Ambiente e Sustentabilidade (CEES). Agradecemos Charles Mooney eo Mecanismo Instrumentação Analítica da Universidade Estadual da Carolina do Norte para obter ajuda com imagem SEM.

1. Preparar Pellets xerogel <ol><li> Síntese gel <ol><li> Adicionar uma 25 milímetros barra de agitação magnética e 113 mL de água de s ionizada para um copo de 500 ml. Magneticamente agitar a água deionizada a uma taxa mais alta que não formam um vórtice. </li><li> Adiciona-se lentamente 13,05 g (0,056 mol) de cloreto de zircónio anidro à água desionizada em pequenos incrementos. Depois de todo o cloreto de zircónio anidro foi dissolvido, adicionar 53,29 g (0,296 mol) de glicose para a solução. </li><li> Depois de toda a glucose foi dissolvida na solução, adicionar 3,73 g (0,01 mol) de hexa-hidrato de nitrato de itrio para a solução. Aumentar a taxa de agitação magnética a ~ 700 rpm e esperar por todo o hexa-hidrato de nitrato de itrio para se dissolver em solução. </li><li> Adicionar 42 ml de óxido de propileno à solução. Continue a agitação a ~ 700 rpm, para o óxido de propileno para se misturar com a solução aquosa. Uma vez que o óxido de propileno é misturado com a solução aquosa (~ 10 s), diminuir a agitação magnética tO ~ 150 rpm. </li><li> Continuar a agitação até que a barra de agitação magnética parou de se mover devido à formação de gel. O gel forma, tipicamente, dentro de 3 min. NOTAS: Adição de cloreto de zircónio anidro a água desionizada é uma reacção fortemente exotérmica e o cloreto de zircónio anidro vai pluma se for adicionado demasiado depressa. A formulação previsto no item 1.1. corresponde a uma glicose aos metais totais (zircónio) + ítrio razão molar de 4,5: 1. A secção de resultados representativos incluem os dados de glicose para proporções totais metais molares de 0: 1, 2,25: 1 e 4,5: 1. A quantidade de glucose na formulação só é limitado pela solubilidade da glucose na solução. Para referência, a solubilidade máxima de glucose em água a 20 ° C é de 47,8% em peso. 15 </li></ol></li><li> Envelhecimento e Lavar o Gel <ol><li> Firmemente cobrir a proveta contendo o gel com Parafilm e deixá-lo idade durante 24 h, deixando o copo coberto à temperatura ambiente. </li><li> Remover a tampa do recipiente e decanta-se o líquido na parte superior do gel. </li><li> Adicionar 300 mL de etanol absoluto a um copo contendo o gel, bem cobrir o copo com Parafilm e deixar o copo coberto à temperatura ambiente durante 24 h. </li><li> Repetir o passo 1.2.3 mais duas vezes para um total de três lavagens de etanol ao longo de um período total de 72 h. </li></ol></li><li> Secagem do gel em um xerogel <ol><li> Remover o gel a partir da proveta e coloca-se numa placa de evaporação de 2 L de porcelana (24 cm de diâmetro exterior superior) usando uma espátula de laboratório. </li><li> Quebrar o gel em cerca de 1 cm x 1 cm pedaços com uma espátula e espalhar-se os pedaços sobre a superfície do prato de evaporação. </li><li> Deixe os pedaços de gel seco em condições ambientais durante uma semana ou até que o gel é seco. O gel é considerada seca quando ele pode ser moído para um pó fino. </li><li> Moer toda a xerogel em um pó fino com um almofariz e pilão. Observação: Uma vez que o gel é seco, éconsiderado um xerogel porque foi seco sob condições ambientais. </li></ol></li><li> Pressionando o xerogel em um Pellet <ol><li> Colocar 1 g de pó de xerogel em uma matriz cilíndrica sedimento prima com um diâmetro de 13 mm. </li><li> Utilizando uma prensa hidráulica, se aplicam 22 kN de força de 90 s para pressionar o gel de xerogel num pelete. </li><li> Liberam lentamente a força aplicada pela imprensa. Lentamente ejectar o sedimento para fora da matriz de sedimento e, em seguida, remover cuidadosamente o sedimento. </li></ol></li></ol> 2. sinterização do xerogel Pellet em uma atmosfera inerte <ol><li> Coloque o sedimento xerogel para uma placa de alumina ou zircónia estabilizada com ítria e carregar o prato para o centro de um forno tubular. </li><li> Fluxo de árgon, a uma taxa de um terço do volume do tubo de trabalho por minuto. Isto corresponde a uma taxa de fluxo de árgon de 750 mL? Min -1 para o tubo de trabalho usado neste trabalho. Purgue a saída de gás de um exaustor de fumos. </li><li> Fluxo de árgon, durante pelo menos 15 min bntes de partida para aquecer o forno de tubo. </li><li> Enquanto que flui continuamente de árgon, a uma taxa constante, o programa controlador de temperatura de forno de tubo com o seguinte esquema de aquecimento: <ol><li> Mantenha à temperatura ambiente durante 15 min. </li><li> Aquece-se a 850 ° C a uma velocidade de rampa de 5 ° C? Min -1. </li><li> Aquecer a temperatura de sinterização desejado a uma velocidade de rampa de 2 ° C · min -1. </li><li> Manter à temperatura de sinterização desejado durante 2 h. </li><li> Arrefece-se até 850 ° C a uma velocidade de rampa de 2 ° C · min -1. </li><li> Arrefecer até à temperatura ambiente a uma velocidade de rampa de 5 ° C? Min -1. </li></ol></li><li> Inicie o programa e dupla verificação de que o forno de tubo está a aquecer-se a seguir o calendário fornecido na secção 2.3. </li><li> Retirar sedimento a partir do forno de tubo depois de o programa de aquecimento foi concluída. </li></ol> 3. determinar a concentração de molde de Carbono <ol><li> Cortar um pedaço mg ~ 50 para fora dopelete xerogel sinterizado com uma faca e moê-lo em um pó fino com um almofariz de ágata e pilão. </li><li> Lugar ~ 50 mg do pó fino, dentro de um copo de amostra de alumina por análise termogravimétrica. </li><li> Utilizando um analisador de termogravimétrica (TGA), a amostra é aquecida a uma taxa de 10 ° C? Min -1 a partir de temperatura ambiente até 1200 ° C, enquanto que flui ar através da amostra a uma taxa de 100 mL? Min -1. </li><li> Calcular a percentagem de alteração no peso que ocorre entre ~ 350 ° C e ~ 700 ° C. Este por cento em peso corresponde ao teor de carbono total na amostra. NOTA: Se ocorre um aumento de peso na 350 ° C a 700 ° C gama, uma fase de carboneto formou e o cálculo do teor de carbono é mais complexo. Para este caso, consulte cálculos descritos na literatura. 14 Análise elementar de carbono tem sido utilizado para confirmar que o teor de carbono pode ser calculado a partir de medições de TGA. </li></ol> 4. Preparar alta Superfície Área YSZ andaime por Template carbono Remoção <ol><li> Coloque o sedimento xerogel sinterizado num cadinho de alumina. </li><li> Colocar o cadinho num forno de caixa a 700 ° C durante 2 h. </li><li> remover cuidadosamente o cadinho quente a partir do forno de caixa com aço inoxidável pinças cadinho e permitir o arrefecimento até à temperatura ambiente durante uma hora antes de remover a poroso, de andaime YSZ branco. </li></ol>

<ol>
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Com esta abordagem de moldação de carbono in situ, pode-se criar e preservar nanomorfologia em misto metal-óxidos a temperaturas de sinterização de cerâmica andaime tradicionais. As áreas de superfície resultantes são até 80 vezes maior do que andaimes tradicionalmente sinterizados e até 4 vezes mais elevados do que andaimes fabricados por técnicas de deposição de complexos. 14 O sistema de gel de óxido de propileno-glicose é altamente flexível para ajustar a concentraç...

A célula de combustível de óxido sólido (SOFC) é uma grande promessa como uma tecnologia de conversão de energia alternativa para a geração eficiente de energia eléctrica limpo. 1 Um progresso considerável foi feito na pesquisa e desenvolvimento desta tecnologia; no entanto, melhorias no desempenho eletrodo ainda são necessários para atingir a comercialização de confiança. O eléctrodo compreende muitas vezes uma estrutura de suporte de cerâmica porosa com as partículas electrocatalíticas decorado na superfície do andaime. Um grande corpo de investigação tem-se centrado em aumentar a área da superfície das partículas electrocatalíticas para aumentar o desempenho, 2, 3, 4, 5, 6, 7, 8, mas não é muito pouco pesquisa sobre o aumento da área de superfície do andaime. O aumento da superfície do andaimeárea é um desafio porque eles são sinterizados a temperaturas elevadas, 1100 ° C a 1500 ° C. Andaimes processados por sinterização tradicional têm tipicamente uma área de superfície específica de 0,1-1 m 2 · g -1. 8, 9, 10, 11 Existem alguns relatórios sobre o aumento da área de superfície do andaime. Em um caso, a área de superfície de um andaime tradicional sinterizado foi reforçada por dissolução e precipitação da superfície do andaime utilizando ácido fluorídrico, atingir uma área de superfície específica de 2 m 2 · g -1. 12 Em outro, altas temperaturas foram totalmente evitados por meio de deposição por laser pulsado, alcançar uma área de superfície específica de 20 m 2 g -1 ·. 13 A lógica por trás do desenvolvimento de nossa técnica era criar uma fabricação de baixo custoprocesso que fornece áreas de superfície de andaime sem precedentes e usa temperaturas de sinterização tradicionais para que o processo possa ser adotadas facilmente. Com a técnica descrita aqui, as áreas de superfície de andaime superior a 80 m 2 g -1 · foram demonstradas enquanto está a ser processado a temperaturas de sinterização tradicionais. 14 Nossa pesquisa é motivado principalmente pela engenharia eletrodo SOFC, mas a técnica é mais amplamente aplicável a outras áreas e aplicações. Geralmente, o método in situ de moldação de carbono é uma abordagem flexível que pode produzir nanoestruturada, da área de superfície elevada misto de metais materiais cerâmicos na forma de pó ou estrutura porosa. É flexível em que a composição cerâmica mista-metal, a área de superfície, a porosidade e o tamanho de poro podem ser sintonizado de forma sistemática. As altas temperaturas são muitas vezes necessários para formar a fase desejada em cerâmica mista de metal, e esta abordagem preserva nanomorfologia cerâmica wnquanto permitindo que se possa escolher, essencialmente, qualquer temperatura de processamento. Este método envolve a síntese de um gel híbrido inorgânico-orgânico baseado no-óxido de propileno, com uma estequiometria bem definir de iões metálicos e a relação de inorgânica para o conteúdo orgânico. O gel é seco sob condições ambientes para formar um xerogel. O xerogel é sinterizado numa atmosfera de árgon à temperatura desejada. Depois do aquecimento, o componente orgânico decompõe-se deixando para trás um modelo de carbono in situ, que permanece durante o período de sinterização. O modelo de carbono é subsequentemente removido por oxidação a baixa temperatura ao ar, resultando num nanoestruturada, elevada área da superfície de cerâmica.

<table><tbody><tr><td>Zirconium(IV) chloride, 99.5+%</td><td>Alfa Aesar</td><td>12104</td><td>Air sensitive</td></tr><tr><td>Yttium(III) nitrate hexadydrate, 99.9%</td><td>Alfa Aesar</td><td>12898</td><td>Oxidizer</td></tr><tr><td>D+ Glucose Anhydrous, &amp;ge;99.5%</td><td>US Biological Life Sciences</td><td>G3050</td><td></td></tr><tr><td>(&amp;plusmn;)-Propylene Oxide, &amp;ge;99%</td><td>Sigma Aldrich</td><td>110205</td><td>Extremely flammable</td></tr><tr><td>Ethanol 200 Proof</td><td>Decon Laboratories, Inc.</td><td>2716GEA</td><td></td></tr><tr><td>Argon, 99.997%</td><td>Airgas</td><td>AR 300</td><td>Industrial grade</td></tr></tbody></table>

high temperature fabrication of nanostructured yttria-stabilized-zirconia (ysz) scaffolds by in situ carbon templating xerogels

Nós demonstramos um método para a fabricação de alta temperatura poroso, nanoestruturada estabilizada com ítria-zircónia (YSZ, 8% molar de óxido de ítrio - 92% em mol de zircónia) andaimes com áreas de superfície específicas sintonizáveis até 80 m 2 g -1 ·. Uma solução aquosa de um sal de zircónio, ítrio sal, e glicose é misturado com óxido de propileno (PO) para formar um gel. O gel é seco sob condições ambientes para formar um xerogel. O xerogel é pressionado em peletes e depois sinterizadas numa atmosfera de árgon. Durante a sinterização, a YSZ formas de fase de cerâmica e os componentes orgânicos decomponha, deixando atrás de carbono amorfo. O carbono formado in situ serve como um molde duro, preservando uma nanomorfologia área de superfície elevada no YSZ temperatura de sinterização. O carbono é subsequentemente removido através de oxidação ao ar a baixa temperatura, resultando em um poroso, andaime nanoestruturada YSZ. A concentração do molde de carbono e a área de superfície andaime final pode ser sistemáticaly sintonizada por variação da concentração de glucose na síntese de gel. A concentração de molde de carbono foi quantificada usando análise termogravimétrica (TGA), a área de superfície e de distribuição de tamanho de poro foi determinado por meio de medições de adsorção física, e a morfologia foi caracterizada utilizando microscopia electrónica de varrimento (MEV). pureza de fase e o tamanho de cristalite foi determinada utilizando difracção de raios-X (DRX). Esta abordagem proporciona uma nova fabricação, plataforma flexível para realizar a áreas de superfície de andaime sem precedentes e nanomorphologies para aplicações cerâmicas à base de conversão de energia electroquímica, por exemplo, células de combustível de óxido sólido (SOFC) eléctrodos.

Pureza fases foi confirmada pela difracção de raios-X (XRD) tal como anteriormente relatado por Cottam et al. 14 YSZ andaime área superficial específica como uma função da concentração de molde de carbono é mostrado na Figura 1. A concentração é apresentado como a percentagem em volume de sólidos totais no sedimento xerogel sinterizado. A concentração de molde de carbono aumenta sistematicamente com o aumento da concentraç...

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High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

Um protocolo para a fabricação de matrizes porosas, nanoestruturada estabilizada com ítria-zircónia (YSZ), a temperaturas entre 1000 ° C e 1400 ° C, é apresentada.

Fabricação de alta temperatura de nanoestruturado ria-Stabilized Zirconia-Scaffolds (ZEI) pela<em&gt; In Situ</em&gt; Carbono Templating xerogéis

We demonstrate a method for the high temperature fabrication of porous, nanostructured yttria-stabilized-zirconia (YSZ, 8 mol% yttria - 92 mol% zirconia) ...

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High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia (YSZ) Scaffolds by In Situ Carbon Templating Xerogels

10.5K visualizações.  Wake Forest University.  Um protocolo para a fabricação de matrizes porosas, nanoestruturada estabilizada com ítria-zircónia (YSZ), a temperaturas entre 1000 ° C e 1400 ° C, é apresentada. 

Vídeo: High Temperature Fabrication of Nanostructured Yttria-Stabilized-Zirconia YSZ Scaffolds by In Situ Carbon Templating Xerogels

Fabrication, Densification, and Replica Molding of 3D Carbon Nanotube Microstructures

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques 1, 2, and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. 
Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT microstructures, significantly increases the packing density of CNTs. This process enables directed transformation of vertical CNT microstructures into straight, inclined, and twisted shapes, which have robust mechanical properties exceeding those of typical microfabrication polymers. This in turn enables formation of nanocomposite CNT master molds by capillary-driven infiltration of polymers. The replica structures exhibit the anisotropic nanoscale texture of the aligned CNTs, and can have walls with sub-micron thickness and aspect ratios exceeding 50:1. Integration of CNT microstructures in fabrication offers further opportunity to exploit the electrical and thermal properties of CNTs, and diverse capabilities for chemical and biochemical functionalization 3.

We present methods for fabrication of patterned microstructures of vertically aligned carbon nanotubes (CNTs), and their use as master molds for production of polymer microstructures with organized nanoscale surface texture. The CNT forests are densified by condensation of solvent onto the substrate, which significantly increases their packing density and enables self-directed formation of 3D shapes.

Fabricação, Densificação e Replica Moldagem de Microestruturas de Nanotubos de Carbono 3D

The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip ...

Engenharia

Preparation and Reactivity of Gasless Nanostructured Energetic Materials

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the balls. Among other applications, it is a versatile technique that allows for effective preparation of gasless reactive nanostructured materials with high energy density per volume (Ni+Al, Ta+C, Ti+C). The structural transformations of reactive media, which take place during HEBM, define the reaction mechanism in the produced energetic&#160;composites. Varying the processing conditions permits fine tuning of the milling-induced microstructures of the fabricated composite particles. In turn, the reactivity, i.e., self-ignition temperature, ignition delay time, as well as reaction kinetics, of high energy density materials depends on its microstructure. Analysis of the milling-induced microstructures suggests that the formation of fresh oxygen-free intimate high surface area contacts between the reagents is responsible for the enhancement of their reactivity. This manifests itself in a reduction of ignition temperature and delay time, an increased rate of chemical reaction, and an overall decrease of the effective activation energy of the reaction. The protocol provides a detailed description for the preparation of reactive nanocomposites with tailored microstructure using short-term HEBM method. It also describes a high-speed thermal imaging technique to determine the ignition/combustion characteristics of the energetic materials. The protocol can be adapted to preparation and characterization of a variety of nanostructured energetic composites.

This protocol describes the preparation of gasless nanostructured energetic materials (Ni+Al, Ta+C, Ti+C) using the short-term high-energy ball milling (HEBM) technique. It also describes a high-speed thermal imaging method to study the reactivity of mechanically fabricated nanocomposites. These protocols can be extended to other reactive nanostructured energetic materials.

Preparação e reactividade de Gasless Nanostructured materiais energéticos

High-Energy Ball Milling (HEBM) is a ball milling process where a powder mixture placed in the ball mill is subjected to high-energy collisions from the ...

Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk. The primary advantage of AD is that the deposition takes place entirely at ambient temperature; thereby enabling film growth in material systems with disparate melting temperatures. This report describes in detail the processing steps for preparing the powder and for performing AD using the custom-built system. Representative characterization results are presented from scanning electron microscopy, profilometry, and ferromagnetic resonance for films grown in this system. As a representative overview of the capabilities of the system, focus is given to a sample produced following the described protocol and system setup. Results indicate that this system can successfully deposit 11 &#181;m thick yttrium iron garnet films that are &#160;&#62; 90% of the bulk density during a single 5 min deposition run. A discussion of methods to afford better control of the aerosol and particle selection for improved thickness and roughness variations in the film is provided.

This report describes the use of a custom-built system to perform aerosol deposition of thick films of yttrium iron garnet onto sapphire substrates at RT. The deposited films are characterized using scanning electron microscopy, profilometry, and ferromagnetic resonance to give a representative overview of the capabilities of the technique.

Formação de espessas densas ítrio Ferro Garnet Films Usando Aerosol Deposição

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% ...

Aerosol-assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, their high cost production and/or incompatibility with microfabrication technologies, due to the use of pre-deposited catalyst-seeds and/or high processing temperatures exceeding 900 &#176;C, represent a drawback for a widespread use of these methods. Here, however, we report the synthesis of ZnO rods via a non-catalyzed vapor-solid mechanism enabled by using an aerosol-assisted chemical vapor deposition (CVD) method at 400 &#176;C with zinc chloride (ZnCl2) as the precursor and ethanol as the carrier solvent. This method provides both single-step formation of ZnO rods and the possibility of their direct integration with various substrate types, including silicon, silicon-based micromachined platforms, quartz, or high heat resistant polymers. This potentially facilitates the use of this method at a large-scale, due to its compatibility with state-of-the-art microfabrication processes for device manufacture. This report also describes the properties of these structures (e.g., morphology, crystalline phase, optical band gap, chemical composition, electrical resistance) and validates its gas sensing functionality towards carbon monoxide.

Columnar zinc oxide structures in the form of rods are synthesized via aerosol-assisted chemical vapor deposition without the use of pre-deposited catalyst-seed particles. This method is scalable and compatible with various substrates based on either silicon, quartz or polymers.

Aerossol-assistida de deposição de Vapor químico de estruturas de óxido de Metal: hastes de óxido de zinco

Whilst columnar zinc oxide (ZnO) structures in the form of rods or wires have been synthesized previously by different liquid- or vapor-phase routes, ...

Química

Chemical Synthesis of Porous Barium Titanate Thin Film and Thermal Stabilization of Ferroelectric Phase by Porosity-Induced Strain

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its well-balanced ferroelectricity, piezoelectricity, and dielectric constant. In addition, BT does not contain any toxic elements. Therefore, it is considered to be an eco-friendly material, which has attracted considerable interest as a replacement for lead zirconate titanate (PZT). However, bulk BT loses its ferroelectricity at approximately 130 &#176;C, thus, it cannot be used at high temperatures. Because of the growing demand for high-temperature ferroelectric materials, it is important to enhance the thermal stability of ferroelectricity in BT. In previous studies, strain originating from the lattice mismatch at hetero-interfaces has been used. However, the sample preparation in this approach requires complicated and expensive physical processes, which are undesirable for practical applications.
In this study, we propose a chemical synthesis of a porous material as an alternative means of introducing strain. We synthesized a porous BT thin film using a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles were used as an organic template. Through a series of studies, we clarified that the introduction of pores had a similar effect on distorting the BT crystal lattice, to that of a hetero-interface, leading to the enhancement and stabilization of ferroelectricity. Owing to its simplicity and cost effectiveness, this fabrication process has considerable advantages over conventional methods.

Here, we present a protocol for the synthesis of porous barium titanate (BaTiO3) thin film by a surfactant-assisted sol-gel method, in which self-assembled amphipathic surfactant micelles are used as an organic template.

Síntese química de película fina de titanato de bário porosa e estabilização térmica da fase ferroelétrica pela tensão induzida pela porosidade

Barium titanate (BaTiO3, hereafter BT) is an established ferroelectric material first discovered in the 1940s and still widely used because of its ...

Multi-material Ceramic-Based Components &#8211; Additive Manufacturing of Black-and-white Zirconia Components by Thermoplastic 3D-Printing (CerAM - T3DP)

To combine the benefits of Additive Manufacturing (AM) with the benefits of Functionally Graded Materials (FGM) to ceramic-based 4D components (three dimensions for the geometry and one degree of freedom concerning the material properties at each position) the Thermoplastic 3D-Printing (CerAM -&#160;T3DP) was developed. It is a direct AM technology which allows the AM of multi-material components. To demonstrate the advantages of this technology black-and-white zirconia components were additively manufactured and co-sintered defect-free.
Two different pairs of black and white zirconia powders were used to prepare different thermoplastic suspensions. Appropriate dispensing parameters were investigated to manufacture single-material test components and adjusted for the additive manufacturing of multi-color zirconia components.

Here we describe a protocol for additively manufacturing black-and-white zirconia components by Thermoplastic 3D-Printing (CerAM -&#160;T3DP) and co-sintering defect-free.

Componentes baseados em cerâmica multi materiais – aditivo de fabricação de componentes de zircônia em preto e branco por impressão 3D termoplástica (CerAM - T3DP)

To combine the benefits of Additive Manufacturing (AM) with the benefits of Functionally Graded Materials (FGM) to ceramic-based 4D components (three ...

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication FFF of Metal-Ceramic Components

This study shows multi-material additive manufacturing (AM) using fused filament fabrication (FFF) of stainless steel and zirconia.

Fabricação de fundidos de filamento (FFF) de componentes de Metal-cerâmica

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with ...

Additive Manufacturing of Functionally Graded Ceramic Materials by Stereolithography

An additive manufacturing technology is applied to obtain functionally graded ceramic parts. This technology, based on digital light processing/stereolithography, is developed within the scope of the CerAMfacturing European research project. A three-dimensional (3-D) hemi-maxillary bone-like structure is 3-D printed using custom aluminum oxide polymeric mixtures. The powders and mixtures are fully analyzed in terms of rheological behavior in order to ensure proper material handling during the printing process. The possibility to print functionally graded materials using the Admaflex technology is explained in this document. Field-emission scanning electron microscopy (FESEM) show that the sintered aluminum oxide ceramic part has a porosity lower than 1% and no remainder of the original layered structure is found after analysis.

This manuscript describes the processing of single multifunctional ceramic components (e.g., combinations of dense-porous structures) additively manufactured by stereolithography.

Fabricação de aditiva de materiais cerâmicos funcionalmente classificados por estereolitografia

An additive manufacturing technology is applied to obtain functionally graded ceramic parts. This technology, based on digital light ...

Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification.

Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Fabricação de Mecanicamente Tunable e Bioativos metal andaimes para aplicações biomédicas

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness ...

Bioengenharia

Epitaxial Nanostructured &alpha;-Quartz Films on Silicon: From the Material to New Devices

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all the steps in the process starting from the material to the device fabrication. The epitaxial growth of &#945;-quartz film on SOI (100) substrate starts with the preparation of a strontium doped silica sol-gel and continues with the deposition of this gel into the SOI substrate in a thin film form using the dip-coating technique under atmospheric conditions at room temperature. Before crystallization of the gel film, nanostructuration is performed onto the film surface by nanoimprint lithography (NIL). Epitaxial film growth is reached at 1000 &#176;C, inducing a perfect crystallization of the patterned gel film. Fabrication of quartz crystal cantilever devices is a four-step process based on microfabrication techniques. The process starts with shaping the quartz surface, and then metal deposition for electrodes follows it. After removing the silicone, the cantilever is released from SOI substrate eliminating SiO2 between silicon and quartz. The device performance is analyzed by non-contact laser vibrometer (LDV) and atomic force microscopy (AFM). Among the different cantilever&#8217;s dimensions included in the fabricated chip, the nanostructured cantilever analyzed in this work exhibited a dimension of 40 &#181;m large and 100 &#181;m long and was fabricated with a 600 nm thick patterned quartz layer (nanopillar diameter and separation distance of 400 nm and 1 &#181;m, respectively) epitaxially grown on a 2 &#181;m thick Si device layer. The&#160;measured&#160;resonance frequency was&#160;267 kHz and the estimated quality factor, Q, of the whole mechanical structure was Q ~ 398 under low vacuum conditions. We observed the voltage-dependent linear displacement of cantilever with both techniques (i.e., AFM contact measurement and LDV). Therefore, proving that these devices can be activated through the indirect piezoelectric effect.

Epitaxial Nanostructured &#945;-Quartz Films on Silicon: From the Material to New Devices

This work presents a detailed protocol for the microfabrication of nanostructured &#945;-quartz cantilever on a Silicon-On-Insulator(SOI) technology substrate starting from the epitaxial growth of quartz film with the dip coating method and then nanostructuration of the thin film via nanoimprint lithography.

Filmes nanoestruturados nanoestruturados de α-quartzo sobre silício: do material aos novos dispositivos

In this work, we show a detailed engineering route of the first piezoelectric nanostructured epitaxial quartz-based microcantilever. We will explain all ...

Fabricação de alta temperatura de nanoestruturado ria-Stabilized Zirconia-Scaffolds (ZEI) pela

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