点蚀形核机制的透射电子显微学研究  

TEM Study on the Pitting Initiation

作　　者：张波[1] 马秀良[1] ZHANG Bo;MA Xiuliang(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所沈阳材料科学国家研究中心,辽宁沈阳110016

出　　处：《中国材料进展》2018年第11期866-879,共14页Materials China

基　　金：国家自然科学基金资助项目(51771212;11327901);中国科学院金属研究所创新基金重点项目(2017-ZD05)

摘　　要：钝性金属材料的点蚀是腐蚀领域中的经典问题。受研究手段空间分辨率的限制,点蚀形核阶段的机制有待进一步阐明。以透射电子显微技术为主要研究手段,围绕与点蚀形核密切相关的材料基体结构特征及钝化膜性质两方面,阐明了点蚀形核的基体结构相关性以及钝化膜结构及与Cl^-的交互作用这两大基本科学问题。在原子尺度下建立了材料基体结构特征与腐蚀溶解活性之间的关联,揭示了钝化膜的结构特征和Cl^-与之交互作用之间的内在规律,丰富、完善甚至修正了材料点蚀形核机制方面的经典认识。研究发现,在点蚀形核初期,无论是基体中夹杂或第二相的腐蚀溶解活性,还是表面钝化膜本身的击破,起源都可以追溯到原子尺度的结构缺陷。Pitting corrosion of passive metals is a classic issue in corrosion field.Over the past decades,the mechanism of pitting corrosion has attracted corrosion community striving to study.However,the mechanism at the pitting initiation stage is still controversy,due to the difficulty encountered in obtaining precise experimental information with enough spatial resolution.Using transmission electron microscopy,we focus on the structure of matrix and the nature of passive film,which are closely related to pitting initiation.This work clarifies the structural origins of the pitting initiation and unmasks the mechanism of chloride-induced passivity breakdown.At the pitting initiation stage,the heterogeneous corrosion activity of inclusions/second phase in matrix,and the preferential attack of the passive film are originated from the atomic-scale structural defects.This work enriches,improves and even modifies the classical understanding on the pitting initiation mechanism.

关 键 词：点蚀 结构缺陷 钝化膜 透射电子显微学 原子尺度 

分 类 号：TG171[金属学及工艺—金属表面处理]