一、前言点腐蚀和缝隙腐蚀是金属和合金在氯化物介质中经常大量出现的局部腐蚀。一般地说,象不锈钢这类易钝化的金属,其表面可能处在三种状态:活化,钝化和过钝化状态。活化和过钝化状态发生均匀腐蚀,而钝化状态的腐蚀速度非常小。在一定条件下(介质中同时存在卤素离子,如氯离子以及氧时)金属或合金表面特殊位置可能丧失其钝化状态,甚至发生非常隐蔽的局部点腐蚀和缝隙腐蚀现象,这种腐蚀,随条件的不同,腐蚀速度可能很快,因而要预测材料的使用年限也就比较困难。材料一旦发生这样的局部腐蚀,即使其他部位没有发现明显腐蚀也要报废。在不锈钢腐蚀的事例中,点腐蚀和缝隙腐蚀占1/3以上。曾调查过石油、化工、钢铁、发电、造纸和食品等工业中发生点 Preface Pitting corrosion and crevice corrosion are localized corrosion of metals and alloys that often occur in large amounts in chloride media. Generally speaking, easily passivated metals such as stainless steel may have surfaces in three states: activated, passivated, and passivated. Activated and over passivated state uniform corrosion, and passivation state corrosion rate is very small. Under certain conditions (the simultaneous presence of halogen ions in the medium, such as chloride ions and oxygen), the specific locations on the surface of the metal or alloy may lose their passivation state, and even very hidden localized pitting and crevice corrosion phenomena occur. Different conditions, the corrosion rate may be fast, so to predict the useful life of the material will be more difficult. In the event of such localized corrosion of the material, it will be scrapped even if no significant corrosion is found elsewhere. In the case of stainless steel corrosion, pitting and crevice corrosion accounted for more than 1/3. Have investigated the oil, chemical, steel, power generation, paper and food industries occurred point