材料(liao)(liao)與周圍非電(dian)解質(zhi)之間發(fa)(fa)生(sheng)純化學作用而引起的(de)腐(fu)(fu)蝕(shi)(shi)損傷稱為化學腐(fu)(fu)蝕(shi)(shi)。其反應(ying)特點是材料(liao)(liao)表(biao)面的(de)原子與非電(dian)解質(zhi)中的(de)氧(yang)化劑(ji)直接發(fa)(fa)生(sheng)氧(yang)化還原反應(ying),腐(fu)(fu)蝕(shi)(shi)產(chan)物生(sheng)成于發(fa)(fa)生(sheng)腐(fu)(fu)蝕(shi)(shi)反應(ying)的(de)表(biao)面,當它較(jiao)牢固地(di)覆蓋在材料(liao)(liao)表(biao)面時,會(hui)減緩(huan)腐(fu)(fu)蝕(shi)(shi)的(de)進一(yi)步發(fa)(fa)生(sheng)。腐(fu)(fu)蝕(shi)(shi)反應(ying)過(guo)程中無電(dian)流產(chan)生(sheng)。

  金屬(shu)和(he)(he)電(dian)解質(zhi)接(jie)觸(chu)時(shi)(shi),由于腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)電(dian)池作(zuo)用而(er)(er)引起(qi)(qi)的(de)(de)(de)金屬(shu)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)現象稱為電(dian)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)。腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)的(de)(de)(de)特(te)點在于,腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)歷程可分(fen)為兩(liang)個相(xiang)對(dui)獨立的(de)(de)(de)并(bing)同(tong)時(shi)(shi)進(jin)行(xing)的(de)(de)(de)陽(yang)(yang)極(ji)(ji)和(he)(he)陰(yin)極(ji)(ji)過(guo)程。特(te)征為受蝕(shi)(shi)(shi)(shi)(shi)(shi)區(qu)是金屬(shu)表(biao)面的(de)(de)(de)陽(yang)(yang)極(ji)(ji),腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)產(chan)物常(chang)常(chang)產(chan)生(sheng)(sheng)(sheng)在陽(yang)(yang)極(ji)(ji)與(yu)陰(yin)極(ji)(ji)之間,不能覆蓋(gai)被(bei)蝕(shi)(shi)(shi)(shi)(shi)(shi)區(qu)域,通常(chang)起(qi)(qi)不到(dao)保(bao)護(hu)作(zuo)用。電(dian)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)和(he)(he)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)的(de)(de)(de)顯著區(qu)別(bie)是腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)過(guo)程中(zhong)有電(dian)流產(chan)生(sheng)(sheng)(sheng)。對(dui)于大多數工(gong)業部門而(er)(er)言,發生(sheng)(sheng)(sheng)電(dian)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)的(de)(de)(de)情(qing)(qing)況遠多于發生(sheng)(sheng)(sheng)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)的(de)(de)(de)情(qing)(qing)況。金屬(shu)發生(sheng)(sheng)(sheng)高溫氧化(hua),表(biao)面生(sheng)(sheng)(sheng)成一定厚度的(de)(de)(de)半導體性質(zhi)的(de)(de)(de)氧化(hua)膜,既可以傳導電(dian)子(zi),也(ye)可以導通離子(zi),此時(shi)(shi)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)不再是單純的(de)(de)(de)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi),而(er)(er)且還包含了電(dian)化(hua)學(xue)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)(shi)。