Electrodeposition of Al alloys by effectively utilizing water

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20493
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0401:Materials engineering, chemical engineering, and related fields
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2021)
• Principal Investigator: Higashino Shota 大阪公立大学, 大学院工学研究科, 助教 (70908095)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: アルミニウム合金 / 電析 / X線吸収端微細構造 / 非水溶媒

Outline of Final Research Achievements

Electrodeposition of aluminum (Al) alloy films has gained increasing interest. Heavy metals such as tungsten(W) and molybdenum are promising alloying elements to improve the corrosion resistance of Al alloys. However, the metal salts of these heavy metals have a low solubility in the Al electrolytes. On the other hand, we recently found that the hydrate salts of W show a high solubility in Al electrolytes. In this study, we attempted to clarify the mechanism of this phenomenon by electrochemical, molecular and X-ray absorption spectroscopic methods. An important finding obtained in this study is that the W hydrate salt in the Al electrolyte has a different dissolution structure than the anhydride salt, suggesting that this may contribute to the increase in solubility.

Free Research Field

電気化学、電気めっき

Academic Significance and Societal Importance of the Research Achievements

Al電解液に添加される金属塩として、これまでは水を含まない無水物のみが使われてきたが、無水物は一般的に溶解度が低いという問題があった。これに対して、本研究では、Al電解液中のW水和物塩は、無水物塩とは異なる特異な溶解構造をもち、かつ高い溶解度を示すことがわかった。この知見は、従来Al電解液において用いられてこなかった水和物塩の有用性を新たに示したという学術的意義をもつ。また、この知見によって、従来は電析することが困難であったAl合金膜が電析可能になったという実用上の意義も大きい。