This work was financially supported in part by The Light Metal Educational Foundation, Inc., Osaka, Japan

1. Material preparation
<ol>
	<li>Use 1 mm thick plates made of an aluminum-magnesium-silicon alloy containing 1 mass% Mg and 0.8 mass% Si (Al-Mg-Si).</li>
	<li>Make test pieces from the Al-Mg-Si alloy plates having a gauge length of 10 mm and width of 5 mm.</li>
	<li>Anneal the test pieces at 520 &#730;C for 1 h using an air furnace. Quench in water as a solution heat treatment.</li>
	<li>Anneal the test pieces at 175 &#730;C for 18 h as a peak aging heat treatment (T6-temper).</li>
	<li>Polish the surface of the test...

<ol>
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J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reducibility+of+oxides+and+sulphides+in+metallurgical+processes.">Reducibility of oxides and sulphides in metallurgical processes.</a> Journal of the Society of Chemical Industry. 63, 125-133 (1944).</li><li>Pourbaix, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Atlas of electrochemical equilibria in aqueous solutions, Ist ed. , 168-176 (1966).</li><li>Young, G. A., Scully, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+diffusion+and+trapping+of+hydrogen+in+high+purity+aluminum.">The diffusion and trapping of hydrogen in high purity aluminum.</a> Acta Materialia. 46, 6337-6349 (1998).</li><li>Smith, S. W., Scully, J. 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The authors have nothing to disclose.

One important aspect of the FW procedure is the attachment of the two specimens to the magnetic stirrer. Because the center of the stirrer bar becomes the non-friction zone, it is best to avoid the attachment of the specimens at the center of the stirrer bar.
Control of the rotation speed of the stirrer bar is also important. When the speed is more than 240 rpm, it becomes difficult to maintain the reaction vessel on the stage of the magnetic stirrer. When the FW procedure is carried out at hi...

In general, aluminum base alloys have higher resistance to environmental hydrogen embrittlement than steel. The high resistance to hydrogen embrittlement of aluminum alloys is due to oxide films on the alloy surface blocking hydrogen entry. To evaluate and compare the high embrittlement sensitivity between aluminum alloys, hydrogen charging is usually performed prior to mechanical testing1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17. However, it is known that hydrogen charging aluminum is not easy, even when utilizing hydrogen charging methods such as cathodic charging15, slow strain rate deformation under humid air16, or hydrogen plasma gas charging17. The difficulty of hydrogen charging aluminum alloys is also due to the oxide films on the aluminum alloy surface. We postulated that higher amounts of hydrogen could be introduced into aluminum alloys if we could remove the oxide film continuously in water. Thermodynamically18, pure aluminum without oxide film reacts easily with water and generates hydrogen. Based on this, we have developed a new method of hydrogen charging of aluminum alloys based on the chemical reaction between water and non-oxide aluminum. This method is able to add high amounts of hydrogen into aluminum alloys in a simple way.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Air furnace</td>
			<td>GC</td>
			<td>QC-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Aluminum alloy plates</td>
			<td>Kobe Steel</td>
			<td></td>
			<td>Al/1.0 mass% Mg/0.8 mass% Si</td>
		</tr>
		<tr>
			<td>Electric balance</td>
			<td>A&#38;D</td>
			<td>HR-200</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass container</td>
			<td></td>
			<td></td>
			<td>Custom made</td>
		</tr>
		<tr>
			<td>Magnetic stirrer</td>
			<td>CORNING</td>
			<td>PC-410D</td>
			<td></td>
		</tr>
		<tr>
			<td>Optical Comparator</td>
			<td>NIKON</td>
			<td>V-12B</td>
			<td></td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>Sato Tech</td>
			<td>PH-230SDJ</td>
			<td></td>
		</tr>
		<tr>
			<td>Quartz tube</td>
			<td></td>
			<td></td>
			<td>Custom made</td>
		</tr>
		<tr>
			<td>Rotary polishing machine</td>
			<td>IMT</td>
			<td>IM-P2</td>
			<td></td>
		</tr>
		<tr>
			<td>Secondary electrom microscope</td>
			<td>JOEL</td>
			<td>JSM-5310LV</td>
			<td></td>
		</tr>
		<tr>
			<td>Sensor gas chromatograph</td>
			<td>FIS Inc.</td>
			<td>SGHA</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon carbide emery paper</td>
			<td>IMT</td>
			<td>531SR</td>
			<td></td>
		</tr>
		<tr>
			<td>Tensile testing machine</td>
			<td>Toshin Kogyo</td>
			<td>SERT-5000-C</td>
			<td></td>
		</tr>
		<tr>
			<td>Tubular furnace</td>
			<td>Honma Riken</td>
			<td></td>
			<td>Custom made</td>
		</tr>
	</tbody>
</table>

hydrogen charging of aluminum using friction in water

A new method of hydrogen charging of aluminum was developed by means of a friction in water (FW) procedure. This procedure can easily introduce high amounts of hydrogen into aluminum based on the chemical reaction between water and non-oxide coated aluminum.

Hydrogen generation/absorption by the FW procedure 
Figure 2 shows the hydrogen generation behavior during the FW procedure of Al-Mg-Si alloys containing different amounts of iron from 0.1 mass % to 0.7 mass %. The specimen continuously emitted a high amount of hydrogen when the stirrer started to rotate. This suggests that hydrogen was generated by a chemical reaction caused by the friction between the alloy surface and water. In addition, the pH value of the water dur...

Watch this Scientific Journal Video about Hydrogen Charging of Aluminum using Friction in Water at JoVE.com

Hydrogen Charging of Aluminum using Friction in Water

In order to introduce high amounts of hydrogen in aluminum and aluminum alloys, a new method of hydrogen charging was developed, called the friction in water procedure.

A new method of hydrogen charging of aluminum was developed by means of a friction in water (FW) procedure. This procedure can easily introduce high ...

When charging aluminum alloys with hydrogen, the presence of oxide film on the surface is a challenge. To solve this problem, we have developed a method that can introduce high amount of hydrogen into aluminum alloys using friction in water. The method is easiest to understand when the rotation of the stir bar and the specimen on the polishing paper can be visualized.Success depends on stabilizing the rotation of the stir bar. Demonstrating the procedure will Ms.Michiko Arayama, an undergraduate student from my laboratory. Fabricate the aluminum alloy test pieces as described in the text.Perform a solution heat treatment by heating the test pieces in an air furnace at 520 degrees Celsius for one hour and then quenching the test pieces in water. For the next step, the peak-aging heat treatment, anneal the test pieces at 175 degrees Celsius for 18 hours. The final step in preparing the test pieces is polishing the surface using silicon carbide emery paper.Before proceeding to the friction in water procedure, weigh and measure the test pieces. Use an electric balance to weigh the test pieces to a precision of 0.0001 grams. Use an optical comparator to measure the thickness and width of the test pieces to a precision of 0.0001 millimeters.The friction in water procedure is carried out in a magnetically stirred custom-made reaction vessel. To begin, use glue to attach two test pieces to a fluorocarbon polymer triangular stir bar. Next, prepare the reaction vessel, a custom-made glass container.Use double-sided tape to attach polishing paper to the inside bottom of the reaction vessel. Place the reaction vessel on the magnetic stirrer. Then place the test pieces and stir bar on top of the polishing paper and the reaction vessel, and add 100 milliliters of distilled water.Place the rubber cover on the reaction vessel. Connect the gas inlet to high-purity argon, and turn on the gas. Connect the gas outlet to a gas chromatograph.Inset the pH probe into the vessel through the rubber cover. Turn on the argon. Once the gas in the reaction vessel as been completely replaced by the argon, the apparatus is ready for charging the aluminum alloy test pieces.Turn on the magnetic stirrer. To stabilize movement of the stir bar in the water, controlling the rotation speed is important. A speed ranging from 60 rpm to 240 rpm is best.Every two minutes, measure the hydrogen concentration using the gas chromatograph, and measure the pH. After one hour, turn off the magnetic stirrer, and remove the test pieces and stir bar from the reaction vessel. To detach the test pieces from the stir bar, immerse them in acetone, and apply ultrasonic vibration for five minutes.Before proceeding to the next step, measure the weight and thickness of the test pieces. Use a tensile test machine to measure the material properties of the test pieces. Set the crosshead speed of the machine to two millimeters per minute.Then measure the stress-strain relationship for the test pieces. To calculate the amount of hydrogen absorbed during the friction in water procedure, first measure the hydrogen released by the test pieces when heated. Cut the test piece to a rectangular shape of one by five by 10 millimeters.Place the test piece inside a quartz tube with a diameter of 10 millimeters, and place the quartz tube in a tubular furnace. Connect the tube to the gas chromatograph and to the argon gas supply. Turn on the flow of argon gas.Heat the quartz tube containing the test piece, increasing the temperature at a constant rate of 200 degrees Celsius per hour until it reaches a temperature of 625 degrees Celsius. While the quartz tube and test piece are being heated, use the gas chromatograph to measure the hydrogen released every two minutes. Aluminum-magnesium-silicon alloys with three different iron concentrations were subjected to the friction in water procedure, 0.1%iron, 0.2%iron, and 0.7%iron.Regardless of the iron concentration, the test pieces emitted large amounts of hydrogen during the procedure. Thermal desorption analysis was performed on both uncharged and hydrogen-charged samples. Regardless of the iron concentration of the alloy, the total hydrogen concentration increased as a result of the friction in water procedure.Compared to the method of pre-stained in humid air, friction in water is an effective method of hydrogen charging an aluminum alloy. Thermal desorption analysis showed a higher hydrogen release rate for alloy charged using the friction in water procedure, and the calculated hydrogen concentration was substantially higher. Compared to uncharged alloy samples, hydrogen-charged alloy samples showed lower ductility.This indicates that the friction in water procedure resulted in hydrogen embrittlement. Secondary electron microscopy was used to examine the fracture morphology of aluminum-magnesium-silicon alloy containing 0.1%iron. After the friction in water procedure, the morphology changed to a grain boundary fracture.This indicates that hydrogen atoms introduced by the friction in water procedure enhanced the decohesion of grain boundaries, leading to hydrogen embrittlement. It is possible to hydrogen-charge aluminum alloys through exposure and humid air with brittle deformation with a slow stirring rate. However, the current method result in a greater amount of hydrogen charging.This method makes it easy for researchers to evaluate the hydrogen embrittlement sensitivity of aluminum alloys that have a variety of different chemical compositions. It may be applied to the development of hydrogen storage materials.

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5.8K 조회수.  Osaka University. 알루미늄 합금에 수소로 충전할 때 표면에 산화물의 존재가 과제입니다. 이 문제를 해결하기 위해, 우리는 물에서 마찰을 사용하여 알루미늄 합금에 수소의 높은 양을 도입 할 수있는 방법을 개발했다. 이 방법은 교반바의 회전과 연마 용지의 시편이 시각화될 수 있는 시기를 이해하는 것이 가장 쉽습니다.성공은 교반 바의 회전을 안정화하는 데 달려 있습니다. 절차를 ...