Development of a high-strength surface coating with an excellent resistance to hydrogen embrittlement

2014 Fiscal Year Final Research Report

• Project/Area Number: 24560102
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Materials/Mechanics of materials
• Research Institution: Kyushu University
• Principal Investigator: YAMABE Junichiro 九州大学, 水素エネルギー国際研究センター, 准教授 (20532336)
• Co-Investigator(Renkei-kenkyūsha): MATSUOKA Saburo 九州大学, 水素材料先端科学研究センター, 特任教授 (10354250) ; STAYKOV Aleksandar 九州大学, カーボンニュートラルエネルギー国際研究所, 助教 (80613231)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 水素 / 皮膜 / 水素脆化 / 水素透過 / 第一原理計算

Outline of Final Research Achievements

Cylindrical specimens (Type 304) with two- and three-layer aluminum-based coatings deposited by a special-blended molten aluminum alloy were exposed to high-pressure hydrogen; then, their hydrogen contents were determined by thermal desorption analysis. The two-layer coating consisted of alumina and Fe-Al layers, whereas the three-layer coating consisted of alumina, aluminum, and Fe-Al layers. The hydrogen-content measurements revealed that the three-layer coating had an excellent resistance to hydrogen entry, compared to the two-layer coating. The excellent resistance of the three-layer coating was attributed to the existence of the aluminum layer, not the alumina layer, which has a good resistance to hydrogen entry in low pressures. Analysis of local hydrogen concentrations by secondary ion mass spectroscopy demonstrated that the extremely low effective hydrogen diffusivity of the three-layer-coated specimen was attributed to hydrogen trapping at the interface of aluminum and Fe-Al.

Free Research Field

材料強度学，水素脆化