我们知道,在外界条件——空气,气体,水,溶液,酸,碱,盐及其他因素——的影响下,金属会受到损坏,由于化学或电化作用所引起的金属表面的损坏现象叫做腐蚀。腐蚀过程是多种多样的,腐蚀现象到处都能碰到,金属生锈就是一种腐蚀现象,腐蚀给国民经济带来了巨大的损失。二十世纪头二十年中的调查结果指出,由于腐蚀引起的金属损失量达每年冶炼出来的金属总量的三分之一,这就是说,全世界每年 We know that metals are damaged under the influence of external conditions - air, gas, water, solution, acids, alkalis, salts and other factors - and the damage of the metal surface due to chemical or electrochemical action is called corrosion . Corrosion process is varied, corrosion can be encountered everywhere, metal rust is a corrosive phenomenon, corrosion has brought huge losses to the national economy. The findings of the first two decades of the twentieth century indicate that metal losses due to corrosion amount to one-third of the total amount of metal smelted each year, which means that every year in the world