金属表面上由于存在异物或结构上的原因而形成缝隙,使缝隙内溶液中与腐蚀有关的物质迁移困难所引起的缝隙内金属的腐蚀,总称为缝隙腐蚀。例如,金属铆接板、螺栓连接的接合部、螺纹接头等情况下金属与金属间形成的缝隙,金属同非金属(包括塑料、橡胶、玻璃等)接触(例如法兰盘垫圈)所形成的缝隙,以及砂粒、灰尘、脏物等沉积在金属表面上所形成的缝隙,等等,都会引起金属缝隙腐蚀。后一情况下的腐蚀又叫沉积腐蚀。几乎所有的金属都可能产生缝隙腐蚀,但以依赖钝化而耐蚀的金属为最容易。几乎所有的腐蚀性介质(包括淡水)都能引起金属缝隙腐蚀,但以含Cl~-离子的溶 The metal surface due to the presence of foreign matter or structural reasons to form a gap, the solution in the gap and corrosion-related substances in the migration of metal caused by the gap corrosion, collectively known as crevice corrosion. For example, gaps formed by metal and metal in the case of metal riveted plates, bolted joints, threaded joints, etc., gaps formed by metal contact with non-metal (including plastic, rubber, glass, etc.) , As well as sand, dust, dirt and other deposited on the metal surface of the formation of the gap, and so on, will cause metal crevice corrosion. In the latter case, the corrosion is called deposition corrosion. Almost all metals can cause crevice corrosion, but it is easiest to rely on passivated and corrosion resistant metals. Almost all corrosive media (including fresh water) can cause metal crevice corrosion, but with Cl ~ - ion-soluble