Elucidation of Corrosion Mechanism for Copper in Organic Acid Environment and Its Application to Microfabrication Technology

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K04763
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Muroran Institute of Technology
• Principal Investigator: SAKAI Masahiro 室蘭工業大学, 大学院工学研究科, 准教授 (20301963)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 銅 / 腐食 / 有機酸 / りん / 定電位保持試験

Outline of Final Research Achievements

Potentiostatically polarized tests of copper tubes in copper formate solution were conducted to investigate the corrosion behavior of pure copper by using electrochemical method. Three kings of copper tubes were used as a specimen; oxygen free copper(OFC) without phosphorous, phosphorous deoxidized copper(PDC) with about 0.02% phosphorous and highly corrosion-resistant copper contains 0.2-0.3% phosphorous.
It takes about one month to generate the corrosion by the immersion test. However, it is possible to reproduce the corrosion for one day by the potentiostatically polarized tests. It is found that the corrosion morphology depends on the phosphorous contents. Ant nest corrosion with branched micropits occurred in the OFC and PDC tubes, while hemispherical pits occurred in the highly corrosion-resistant copper tubes.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

有機酸環境下での銅の腐食は，蟻の巣状腐食と呼ばれ，エアコンなどの身近なインフラでも生じているが，その発生・進展メカニズムは明らかになっていない。今回の研究で，定電位保持試験という電気化学的手法を用いることにより，蟻の巣状腐食の再現を１日で行うことが可能となった。実環境で生じる腐食メカニズムの解明には，その腐食をラボにて再現すること重要となるが，今回それを行うことに成功した。再現試験時のパラメータに着目し，それらを変化させることで蟻の巣状腐食メカニズム解明の一助になるものと思われる。