Corrosion behavior of ultra-fine grained industrial pure Al fabricated by ECAP

来源期刊：中国有色金属学报(英文版)2009年第5期

论文作者：宋丹 马爱斌 江静华 林萍华 杨东辉

文章页码：1065 - 1070

Key words：equal channel angular pressing; ultra-fine grain; corrosion behavior; industrial pure Al

Abstract: Corrosion behavior of ultra-fine grained(UFG) industrial Al fabricated by equal channel angular pressing(ECAP) for 16 pass times was investigated by potentiodynamic polarization test, potentiostatic polarization test, electrochemical impedance spectroscopy(EIS) measurement, immersion test and surface analyses (OM and SEM). The microstructures including grain size, grain boundaries and dislocations were also observed by TEM. The results show that the UFG industrial pure Al has more positive pitting potential, less corrosion current density and five times larger passive film resistance compared with the coarse grained(CG) one. It was found that the increased pitting resistance is profited from the more stable passive film kept in the Cl^- aggressive solution due to more grain boundaries, larger fraction of non-equilibrium grain boundaries and residual stress of the UFG industrial pure Al.