材(cai)料與(yu)周(zhou)圍(wei)非電解(jie)質之(zhi)間發(fa)生(sheng)(sheng)(sheng)純化學作用(yong)而引起的腐(fu)(fu)蝕(shi)損傷稱為化學腐(fu)(fu)蝕(shi)。其反(fan)應(ying)特點是材(cai)料表面的原(yuan)子與(yu)非電解(jie)質中(zhong)的氧化劑直接發(fa)生(sheng)(sheng)(sheng)氧化還原(yuan)反(fan)應(ying),腐(fu)(fu)蝕(shi)產物生(sheng)(sheng)(sheng)成于發(fa)生(sheng)(sheng)(sheng)腐(fu)(fu)蝕(shi)反(fan)應(ying)的表面,當它較牢固地覆蓋在(zai)材(cai)料表面時,會(hui)減(jian)緩(huan)腐(fu)(fu)蝕(shi)的進一步發(fa)生(sheng)(sheng)(sheng)。腐(fu)(fu)蝕(shi)反(fan)應(ying)過(guo)程(cheng)中(zhong)無(wu)電流(liu)產生(sheng)(sheng)(sheng)。

  金(jin)屬和電(dian)解(jie)質(zhi)接觸(chu)時(shi)(shi),由于(yu)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)池作用而引(yin)起的金(jin)屬腐(fu)(fu)(fu)蝕(shi)(shi)(shi)現象稱(cheng)為電(dian)化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)。腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的特點在于(yu),腐(fu)(fu)(fu)蝕(shi)(shi)(shi)歷程(cheng)可(ke)分為兩個(ge)相對獨(du)立(li)的并同時(shi)(shi)進(jin)行的陽極(ji)和陰極(ji)過程(cheng)。特征為受蝕(shi)(shi)(shi)區是金(jin)屬表面(mian)的陽極(ji),腐(fu)(fu)(fu)蝕(shi)(shi)(shi)產(chan)物常(chang)常(chang)產(chan)生(sheng)在陽極(ji)與陰極(ji)之間,不能覆蓋被蝕(shi)(shi)(shi)區域,通(tong)(tong)常(chang)起不到保護作用。電(dian)化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)和化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的顯著區別(bie)是腐(fu)(fu)(fu)蝕(shi)(shi)(shi)過程(cheng)中有電(dian)流產(chan)生(sheng)。對于(yu)大多數工業部門而言(yan),發(fa)(fa)生(sheng)電(dian)化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的情況遠多于(yu)發(fa)(fa)生(sheng)化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的情況。金(jin)屬發(fa)(fa)生(sheng)高溫(wen)氧(yang)(yang)化(hua)(hua),表面(mian)生(sheng)成一定厚度的半導(dao)體性質(zhi)的氧(yang)(yang)化(hua)(hua)膜,既可(ke)以傳導(dao)電(dian)子,也可(ke)以導(dao)通(tong)(tong)離(li)子,此時(shi)(shi)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)不再是單純的化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi),而且還包含了電(dian)化(hua)(hua)學(xue)(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)。