材料與周圍非(fei)電解質之間(jian)發生純化學(xue)作用而(er)引起的(de)腐蝕(shi)(shi)損傷稱為化學(xue)腐蝕(shi)(shi)。其反應特點(dian)是材料表(biao)(biao)(biao)面的(de)原子與非(fei)電解質中的(de)氧化劑直接發生氧化還原反應,腐蝕(shi)(shi)產(chan)物生成于發生腐蝕(shi)(shi)反應的(de)表(biao)(biao)(biao)面,當它較牢固地覆蓋在材料表(biao)(biao)(biao)面時,會減(jian)緩腐蝕(shi)(shi)的(de)進一步發生。腐蝕(shi)(shi)反應過(guo)程中無(wu)電流產(chan)生。

  金屬(shu)和(he)電(dian)(dian)(dian)解質接觸時,由(you)于腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)電(dian)(dian)(dian)池(chi)作用而(er)(er)引(yin)起的(de)(de)金屬(shu)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)現象稱為(wei)電(dian)(dian)(dian)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)。腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)特點在(zai)于,腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)歷程(cheng)可分為(wei)兩個相對獨立的(de)(de)并同時進(jin)行的(de)(de)陽(yang)極和(he)陰(yin)極過(guo)程(cheng)。特征為(wei)受蝕(shi)(shi)(shi)(shi)(shi)區(qu)是(shi)金屬(shu)表面的(de)(de)陽(yang)極,腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)產物常(chang)常(chang)產生(sheng)(sheng)(sheng)在(zai)陽(yang)極與陰(yin)極之間,不(bu)能覆(fu)蓋被蝕(shi)(shi)(shi)(shi)(shi)區(qu)域,通常(chang)起不(bu)到保(bao)護(hu)作用。電(dian)(dian)(dian)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)和(he)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)顯著區(qu)別是(shi)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)過(guo)程(cheng)中有電(dian)(dian)(dian)流產生(sheng)(sheng)(sheng)。對于大多數工業部門而(er)(er)言,發生(sheng)(sheng)(sheng)電(dian)(dian)(dian)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)情(qing)況遠多于發生(sheng)(sheng)(sheng)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)情(qing)況。金屬(shu)發生(sheng)(sheng)(sheng)高溫氧化(hua)(hua)(hua),表面生(sheng)(sheng)(sheng)成一定(ding)厚度的(de)(de)半導(dao)體性質的(de)(de)氧化(hua)(hua)(hua)膜(mo),既(ji)可以(yi)傳導(dao)電(dian)(dian)(dian)子(zi),也(ye)可以(yi)導(dao)通離子(zi),此(ci)時腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)不(bu)再(zai)是(shi)單(dan)純的(de)(de)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi),而(er)(er)且(qie)還包(bao)含了電(dian)(dian)(dian)化(hua)(hua)(hua)學腐(fu)(fu)(fu)蝕(shi)(shi)(shi)(shi)(shi)。