Name: metal corrosion and the efficiency of corrosion inhibitors in less conductive media
Uploaded: 2018-11-03T13:00:00
Description: Watch this Scientific Journal Video about Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media at JoVE.com

This research was funded from the institutional support for the long-term conceptual development of the research organization (company registration number CZ60461373) provided by the Ministry of Education, Youth and Sports, the Czech Republic, the Operational Programme Prague - Competitiveness (CZ.2.16/3.1.00/24501) and &#34;National Programme of Sustainability&#34; (NPU I LO1613) MSMT-43760/2015).

1. The Static Immersion Corrosion Test in Metal-Liquid Systems
<ol>
	<li>Add 100&#8211;150 mL of the tested liquid corrosion environment for testing the resistance of metallic materials or the efficiency of corrosion inhibitors (i.e., aggressive EGB contaminated with water and trace amounts of chlorides, sulfates and acetic acid) into a 250 mL bottle equipped with a hook for hanging an analyzed sample (Figure 1).</li>
	<li>Adjust the surface of the metallic samples by grinding using sandpaper ...

<ol>
	<li>Revie, R. W., Uhlig, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Corrosion and corrosion control: An Introduction to corrosion science and engineering, 4th edition. , (2008).</li><li>Edwards, R., Mahieu, V., Griesemann, J. -. C., Lariv&#233;, J. -. F., Rickeard, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Well-to-wheels+analysis+of+future+automotive+fuels+and+powertrains+in+the+European+context.+Report+No.+0148-7191.">Well-to-wheels analysis of future automotive fuels and powertrains in the European context. Report No. 0148-7191.</a> SAE Technical Paper. , (2004).</li><li>. Directive 2009/28/ES. On the promotion of the use of energy from renewable rources and amending and subsequently repealing Directives 2001/77/EC and 2003/77/EC Available from: <a target="_blank" href="https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=celex%3A32009L0028">https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=celex%3A32009L0028</a> (2009)</li><li>Tshiteya, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Properties of alcohol transportation fuels. , (1991).</li><li>Battino, R., Rettich, T. R., Tominaga, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+solubility+of+oxygen+and+ozone+in+liquids.">The solubility of oxygen and ozone in liquids.</a> Journal of Physical and Chemical Reference Data. 12 (2), 163-178 (1983).</li><li>Hsieh, W. -. D., Chen, R. -. H., Wu, T. -. L., Lin, T. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engine+performance+and+pollutant+emission+of+an+SI+engine+using+ethanol-gasoline+blended+fuels.">Engine performance and pollutant emission of an SI engine using ethanol-gasoline blended fuels.</a> Atmospheric Environment. 36 (3), 403-410 (2002).</li><li>Pereira, R. C., Pasa, V. M. <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+mono-olefins+and+diolefins+on+the+stability+of+automotive+gasoline.">Effect of mono-olefins and diolefins on the stability of automotive gasoline.</a> Fuel. 85 (12), 1860-1865 (2006).</li><li>Schweitzer, P. 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> Fundamentals of corrosion: mechanisms, causes, and preventative methods. , (2009).</li><li>Migahed, M., Al-Sabagh, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beneficial+role+of+surfactants+as+corrosion+inhibitors+in+petroleum+industry:+a+review+article.">Beneficial role of surfactants as corrosion inhibitors in petroleum industry: a review article.</a> Chemical Engineering Communications. 196 (9), 1054-1075 (2009).</li><li>Mac&#225;k, J., #268;ernou&#353;ek, T., Ji&#345;&#237;&#269;ek, I., Baro&#353;, P., Tom&#225;&#353;ek, J., Posp&#237;&#353;il, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elektrochemick&#233;+korozn&#237;+testy+v+kapaln&#253;ch+biopalivech+(Electrochemical+Corrosion+Tests+in+Liquid+Biofuels)+(in+Czech).">Elektrochemick&#233; korozn&#237; testy v kapaln&#253;ch biopalivech (Electrochemical Corrosion Tests in Liquid Biofuels) (in Czech).</a> Paliva. 1 (1), 1-4 (2009).</li><li>Nesic, S., Schubert, A., Brown, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thin+channel+corrosion+flow+cell.">Thin channel corrosion flow cell.</a> International patent. , (2009).</li><li>Blum, S. C., Sartori, G., Robbins, W. K., Monette, L. M. -. A., Vogel, A., Yeganeh, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Process+for+assessing+inhibition+of+petroleum+corrosion.">Process for assessing inhibition of petroleum corrosion.</a> International Patent. , (2003).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Ochrana proti korozi. Inhibitory koroze kov&#367; a slitin v neutr&#225;ln&#237;ch vodn&#237;ch prost&#345;ed&#237;ch. Laboratorn&#237; metody stanoven&#237; ochrann&#233; &#250;&#269;innosti (in Czech). , (1990).</li><li>Mat&#283;jovsk&#253;, L., Baro&#353;, P., Posp&#237;&#353;il, M., Mac&#225;k, J., Straka, P., Maxa, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testov&#225;n&#237;+korozn&#237;ch+vlastnost&#237;+lihobenz&#237;nov&#253;ch+sm&#283;s&#237;+na+oceli,+hlin&#237;ku+m&#283;di+a+mosazi+(Testing+of+Corrosion+Properties+of+Ethanol-Gasoline+Blends+on+Steel,+Aluminum,+Copper+and+Brass)+(in+Czech).">Testov&#225;n&#237; korozn&#237;ch vlastnost&#237; lihobenz&#237;nov&#253;ch sm&#283;s&#237; na oceli, hlin&#237;ku m&#283;di a mosazi (Testing of Corrosion Properties of Ethanol-Gasoline Blends on Steel, Aluminum, Copper and Brass) (in Czech).</a> Paliva. 5 (2), 54-62 (2013).</li><li>Cempirkova, D., Hadas, R., Mat&#283;jovsk&#253;, L., Sauerstein, R., Ruh, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+E100+Fuel+on+Bearing+Materials+Selection+and+Lubricating+Oil+Properties.">Impact of E100 Fuel on Bearing Materials Selection and Lubricating Oil Properties.</a> SAE Technical Paper. , (2016).</li><li>Yoo, Y., Park, I., Kim, J., Kwak, D., Ji, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corrosion+characteristics+of+aluminum+alloy+in+bio-ethanol+blended+gasoline+fuel:+Part+1.+The+corrosion+properties+of+aluminum+alloy+in+high+temperature+fuels.">Corrosion characteristics of aluminum alloy in bio-ethanol blended gasoline fuel: Part 1. The corrosion properties of aluminum alloy in high temperature fuels.</a> Fuel. 90 (3), 1208-1214 (2011).</li><li>Bhola, S. M., Bhola, R., Jain, L., Mishra, B., Olson, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corrosion+behavior+of+mild+carbon+steel+in+ethanolic+solutions.">Corrosion behavior of mild carbon steel in ethanolic solutions.</a> Journal of Materials Engineering and Performance. 20 (3), 409-416 (2011).</li><li>Jafari, H., Idris, M. H., Ourdjini, A., Rahimi, H., Ghobadian, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EIS+study+of+corrosion+behavior+of+metallic+materials+in+ethanol+blended+gasoline+containing+water+as+a+contaminant.">EIS study of corrosion behavior of metallic materials in ethanol blended gasoline containing water as a contaminant.</a> Fuel. 90 (3), 1181-1187 (2011).</li><li>Traldi, S., Costa, I., Rossi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corrosion+of+spray+formed+Al-Si-Cu+alloys+in+ethanol+automobile+fuel.">Corrosion of spray formed Al-Si-Cu alloys in ethanol automobile fuel.</a> Key Engineering Materials. , 352-357 (2001).</li><li>Nie, X., Li, X., Northwood, D. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corrosion+Behavior+of+metallic+materials+in+ethanol-gasoline+alternative+fuels.">Corrosion Behavior of metallic materials in ethanol-gasoline alternative fuels.</a> Material Science Forum. 546, 1093-1100 (2007).</li><li>Sridhar, N., Price, K., Buckingham, J., Dante, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+corrosion+cracking+of+carbon+steel+in+ethanol.">Stress corrosion cracking of carbon steel in ethanol.</a> Corrosion. 62 (8), 687-702 (2006).</li><li>Mate&#780;jovsky&#769;, L., Mac&#225;k, J., Pospi&#769;s&#780;il, M., Baros&#780;, P., Stas&#780;, M., Krausova&#769;, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+of+Corrosion+of+Metallic+Materials+in+Ethanol-Gasoline+Blends:+Application+of+Electrochemical+Methods.">Study of Corrosion of Metallic Materials in Ethanol-Gasoline Blends: Application of Electrochemical Methods.</a> Energy &amp; Fuels. 31 (10), 10880-10889 (2017).</li><li>Mat&#283;jovsk&#253;, L., Mac&#225;k, J., Posp&#237;&#353;il, M., Sta&#353;, M., Baro&#353;, P., Krausov&#225;, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+of+Corrosion+Effects+of+Oxidized+Ethanol-Gasoline+Blends+on+Metallic+Materials.">Study of Corrosion Effects of Oxidized Ethanol-Gasoline Blends on Metallic Materials.</a> Energy Fuels. 32 (4), 5145-5156 (2018).</li></ol>

The basic principle of the dynamic test and both static tests is the evaluation of weight losses of metallic samples in metal-corrosion environment (fuel) systems depending on time until steady state is achieved (i.e., no further weight loss occurs). The corrosion rate of the metal in the corrosion environment is calculated from the weight loss and time. The advantage of the long-term static corrosion test (Step 1) is the reliability of the obtained results, the simplicity and l...

Corrosion causes great material and economic damage around the world. It causes considerable material losses due to partial or complete material disintegration. The released particles can be understood as impurities; they can negatively change the composition of the surrounding environment or the functionality of various devices. Also, corrosion can cause negative visual changes of materials. Thus, there is a need to understand corrosion processes in more detail to develop measures to prevent corrosion and minimize its potential risks1.
Considering environmental issues and the limited fossil fuel reserves, there is an increasing interest in alternative fuels, among which biofuels from renewable sources play an important role. There are a number of different potentially available biofuels, but bioethanol produced from biomass currently is the most suitable alternative for substituting (or blending with) gasolines. The use of bioethanol is regulated by the Directive 2009/28/EC in the European Union2,3.
Ethanol (bioethanol) has substantially different properties in comparison with gasolines. It is highly polar, conductive, completely miscible with water, etc. These properties make ethanol (and fuel blends containing ethanol also) aggressive in terms of corrosion4. For fuels with low ethanol content, contamination by small amounts of water can cause separation of the water-ethanol phase from the hydrocarbon phase and this can be highly corrosive. Anhydrous ethanol itself can be aggressive for some less noble metals and cause &#34;dry corrosion&#34;5. With existing cars, corrosion can occur in some metallic parts (especially from copper, brass, aluminum or carbon steel) that come into contact with the fuel. Furthermore, polar contaminants (especially chlorides) may contribute to the corrosion as a source of contamination; oxygen solubility and oxidation reactions (that can occur in ethanol-gasoline blends (EGBs) and be a source of acidic substances) can also play an important role6,7.
One of the possibilities on how to protect metals from corrosion is the use of so-called corrosion inhibitors that make it possible to substantially slow down (inhibit) corrosion processes8. The selection of corrosion inhibitors depends on the type of corrosive environment, the presence of corrosion stimulators, and particularly on the mechanism of a given inhibitor. Currently, there is no versatile database or classification available that would enable simple orientation in corrosion inhibitors.
Corrosion environments can be divided into aqueous or non-aqueous, as the intensity and the nature of corrosion processes in these environments differ significantly. For non-aqueous environments, electrochemical corrosion connected with different chemical reactions is typical, whereas only electrochemical corrosion (without other chemical reactions) occurs in aqueous environments. Moreover, electrochemical corrosion is much more intensive in aqueous environments9.
In non-aqueous, liquid organic environments, corrosion processes depend on the degree of polarity of the organic compounds. This is associated with the substitution of hydrogen in some functional groups by metals, which is connected with the change of the characteristics of the corrosion processes from electrochemical to chemical, for which lower corrosion rates are typical in comparison with electrochemical processes. Non-aqueous environments typically have low values of electrical conductivity9. To increase conductivity in organic environments, it is possible to add so called supporting electrolytes such as tetraalkylammonium tetrafluoroborates or perchlorates. Unfortunately, these substances can have inhibitive properties, or, on the contrary, increase corrosion rates10.
There are several methods for short-term and long-term testing of corrosion rates of metallic materials or the efficiency of corrosion inhibitors, namely with or without environment circulation, i.e., static and dynamic corrosion test, respectively11,12,13,14,15. For both methods, the calculation of the corrosion rates of metallic materials is based on weight losses of the tested materials over a certain time period. Recently, electrochemical methods are becoming more important in corrosion studies due to their high efficiency and short measurement times. Moreover, they can often provide more information and a more comprehensive view on corrosion processes. The most commonly used methods are electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and the measurement of the stabilization of the corrosion potential in time (in a planar, two-electrode or in a three electrode arrangement)16,17,18,19,20,21,22,23.
Here, we present five methods for the short-term and long-term testing of the corrosion aggressiveness of an environment, the corrosion resistance of metallic materials and the efficiency of corrosion inhibitors. All of the methods are optimized for measurements in non-aqueous environments and are demonstrated on EGBs. The methods allow for obtaining representative and reproducible results, which can help to understand corrosion processes in more detail to prevent and minimize corrosion damages.
For the static immersion corrosion test in metal-liquid systems, static corrosion tests in metal-liquid systems can be performed in a simple apparatus consisting of a 250 mL bottle equipped with a hook for hanging an analyzed sample, see Figure 1.
For the dynamic corrosion test with liquid circulation, metal corrosion inhibitors or the aggressiveness of liquids (fuels) can be tested in a flow apparatus with the circulation of the liquid medium presented in Figure 2. The flow apparatus consists of a tempered part and a reservoir of the tested liquid. In the tempered part, the tested liquid is in contact with a metallic sample in the presence of air oxygen or in an inert atmosphere. The gas (air) supply is ensured by a frit with the tube reaching the bottom of the flask. The reservoir of the tested liquid containing about 400-500 mL of the tested liquid is connected with a reflux cooler that allows for the connection of the apparatus with the atmosphere. In the cooler, the evaporated portion of the liquid is frozen at -40 &#176;C. The peristaltic pump allows for the pumping of the liquid at a suitable rate of about 0.5 Lh-1 via a closed circuit from chemically stable and inert materials (e.g., Teflon, Viton, Tygon) from the storage part into the tempered part, from which the liquid returns via the overflow into the storage part.
For the static immersion corrosion test with a reflux cooler in the presence of gaseous medium, corrosion inhibitors, the resistance of metallic materials or the aggressiveness of a liquid environment can be tested in the apparatus presented in Figure 3. The apparatus contains two parts. The first part consists of a two-necked, tempered 500 mL flask with a thermometer. The flask contains a sufficient amount of a liquid environment. The second part consists of (i) a reflux cooler with a ground glass joint to achieve a tight connection with the flask, (ii) a hanger for placing the metallic samples and (iii) a frit with a tube for gas (air) supply reaching the bottom of the flask. The apparatus is connected to the atmosphere via the cooler that avoids liquid evaporation.
The apparatus for the electrochemical measurements in the two-electrode arrangement is presented in Figure 4. The electrodes are made from metal sheets (3 x 4 cm, from mild steel), which are completely embedded in epoxide resin on one side to protect them from the surrounding corrosive environment. Both electrodes are screwed to the matrix so that the distance between them is about 1 mm22.
The electrochemical measurements in the three-electrode arrangement consist of working, reference and auxiliary electrodes placed in the measuring cell so that a small distance between the electrodes is ensured; see Figure 5. As the reference electrode, calomel or argent-chloride electrodes with a salt bridge containing either (i) a 3 molL-1solution of potassium nitrate (KNO3) or (ii) a 1 molL-1solution of lithium chloride (LiCl) in ethanol can be used. A platinum wire, mesh or plate can be used as the auxiliary electrode. The working electrode consists of (i) a measuring part (tested material with a screw thread) and (ii) a screw attachment isolated from the corrosion environment, see Figure 6. The electrode must be sufficiently isolated by an anti-underflow seal.

<table>
	<tbody>
		<tr>
			<td>sulfuric acid</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td>20450-11000</td>
			<td>p.a. 96 % 
			CAS: 7664-93-9 
			http://www.pentachemicals.eu/</td>
		</tr>
		<tr>
			<td>acetic acid</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td>20000-11000</td>
			<td>p.a. 99 % 
			CAS: 64-19-7 
			http://www.pentachemicals.eu/</td>
		</tr>
		<tr>
			<td>sodium sulphate anhydrous</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td>25770-31000</td>
			<td>p.a. 99,9 % 
			CAS: 7757-82-6 
			http://www.pentachemicals.eu/</td>
		</tr>
		<tr>
			<td>sodium chlorate</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td></td>
			<td>p.a. 99,9 % 
			CAS:&#160;7681-52-9 
			http://www.pentachemicals.eu/</td>
		</tr>
		<tr>
			<td>demineralized water</td>
			<td>-</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ethanol</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td>71250-11000</td>
			<td>p.a. 99 %&#160; 
			CAS: 64-17-5 
			http://www.pentachemicals.eu/</td>
		</tr>
		<tr>
			<td>gasoline fractions</td>
			<td>Cesk&#225; rafinersk&#225; a.s., Kralupy nad Vltavou, Czech Republic</td>
			<td></td>
			<td>in compliance with EN 228 (57.4 vol. % of saturated hydrocarbons, 13.9 vol. % of olefins, 28.7 vol. % of aromatic hydrocarbons, and 1 mg/kg of sulfur)</td>
		</tr>
		<tr>
			<td>Aceton</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td></td>
			<td>pure 99 %</td>
		</tr>
		<tr>
			<td>Toluen</td>
			<td>Penta s.r.o., Czech Republic</td>
			<td></td>
			<td>pure 99 %</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Potenciostat/Galvanostat/ZRA</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Reference 600</td>
			<td>Gamry Instruments, USA</td>
			<td></td>
			<td>https://www.gamry.com/</td>
		</tr>
		<tr>
			<td>1250 Frequency Response Analyser</td>
			<td>Solarthrone</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SI 1287 Elecrtochemical Interference</td>
			<td>Solarthrone</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Framework 5.68</td>
			<td>Gamry Instruments, USA</td>
			<td></td>
			<td>https://www.gamry.com/</td>
		</tr>
		<tr>
			<td>Echem Analyst 5.68</td>
			<td>Gamry Instruments, USA</td>
			<td></td>
			<td>https://www.gamry.com/</td>
		</tr>
		<tr>
			<td>Corrware 2.5b</td>
			<td>Scribner</td>
			<td></td>
			<td>http://www.scribner.com/</td>
		</tr>
		<tr>
			<td>CView 2.5b</td>
			<td>Scribner</td>
			<td></td>
			<td>http://www.scribner.com/</td>
		</tr>
		<tr>
			<td>Zview 3.2c</td>
			<td>Scribner</td>
			<td></td>
			<td>http://www.scribner.com/</td>
		</tr>
		<tr>
			<td>MS Excel 365</td>
			<td>Microsoft</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Grinder</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Kompak 1031</td>
			<td>MTH (Materials Testing Hrazdil)</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

metal corrosion and the efficiency of corrosion inhibitors in less conductive media

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, prevent them and minimize the damages associated with them. One of the most important characteristics of corrosion processes is the corrosion rate. The measurement of corrosion rates is often very difficult or even impossible especially in less conductive, non-aqueous environments such as biofuels. Here, we present five different methods for the determination of corrosion rates and the efficiency of anti-corrosion protection in biofuels: (i) a static test, (ii) a dynamic test, (iii) a static test with a reflux cooler and electrochemical measurements (iv) in a two-electrode arrangement and (v) in a three-electrode arrangement. The static test is advantageous due to its low demands on material and instrumental equipment. The dynamic test allows for the testing of corrosion rates of metallic materials at more severe conditions. The static test with a reflux cooler allows for the testing in environments with higher viscosity (e.g., engine oils) at higher temperatures in the presence of oxidation or an inert atmosphere. The electrochemical measurements provide a more comprehensive view on corrosion processes. The presented cell geometries and arrangements (the two-electrode and three-electrode systems) make it possible to perform measurements in biofuel environments without base electrolytes that could have a negative impact on the results and load them with measurement errors. The presented methods make it possible to study the corrosion aggressiveness of an environment, the corrosion resistance of metallic materials, and the efficiency of corrosion inhibitors with representative and reproducible results. The results obtained using these methods can help to understand corrosion processes in more detail to minimize the damages caused by corrosion.

The above mentioned methods were used to measure the corrosion data of mild steel (consisting of 0.16 wt. % of C, 0.032 wt. % of P, 0.028 wt. % of S and balance F)22 in the environment of ethanol-gasoline blends (EGBs) containing 10 and 85 vol. % of ethanol (E10 and E85), respectively. For the preparation of these EGBs, gasoline in compliance with the requirements of the EN 228 containing 57.4 vol. % of saturated hydrocarbons, 13.9 vol. % of olefins, 28.7 vol. % of...

Watch this Scientific Journal Video about Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media at JoVE.com

Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media

The testing of processes associated with material corrosion can often be difficult especially in non-aqueous environments. Here, we present different methods for short-term and long-term testing of corrosion behavior of non-aqueous environments such as biofuels, especially those containing bioethanol.

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, ...

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Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays

Much of the nutrient cycling and carbon  processing in natural environments occurs through the activity of extracellular  enzymes released by ...

Clean Sampling and Analysis of River and Estuarine Waters for Trace Metal Studies

Most of the trace metal concentrations in ambient waters obtained a few decades ago have been considered unreliable owing to the lack of contamination ...

Potentiodynamic Corrosion Testing

Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation ...

Determination of Inorganic Arsenic in a Wide Range of Food Matrices using Hydride Generation - Atomic Absorption Spectrometry.

The European Food Safety Authority (EFSA) underlined in its Scientific Opinion on Arsenic in Food that in order to support a sound exposure assessment to ...

Dispersion of Nanomaterials in Aqueous Media: Towards Protocol Optimization

The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and ...

Microfluidic Devices for Characterizing Pore-scale Event Processes in Porous Media for Oil Recovery Applications

Microfluidic devices are versatile tools for studying transport processes at a microscopic scale. A demand exists for microfluidic devices that are ...

Thermal Scanning Conductometry (TSC) as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels

Thermal Scanning Conductometry TSC as a General Method for Studying and Controlling the Phase Behavior of Conductive Physical Gels

The thermal scanning conductometry protocol is a new approach in studying ionic gels based on low molecular weight gelators. The method is designed to ...

The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea

The Plant Infection Test: Spray and Wound-Mediated Inoculation with the Plant Pathogen Magnaporthe Grisea

Plants possess a powerful system to defend themselves against potential threats by pathogenic fungi. For agriculturally important plants, however, current ...

Leaf Area Index Estimation Using Three Distinct Methods in Pure Deciduous Stands

Accurate estimations of leaf area index (LAI), defined as half of the total leaf surface area per unit of horizontal ground surface area, are crucial for ...

Combining Fluidic Devices with Microscopy and Flow Cytometry to Study Microbial Transport in Porous Media Across Spatial Scales

Understanding the transport, dispersion and deposition of microorganisms in porous media is a complex scientific task comprising topics as diverse as ...