材(cai)(cai)料與周圍非(fei)(fei)電解質之間發生(sheng)(sheng)純化(hua)學(xue)(xue)作(zuo)用而引起的腐(fu)(fu)(fu)(fu)(fu)蝕(shi)損傷(shang)稱為化(hua)學(xue)(xue)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)。其反(fan)應特點是材(cai)(cai)料表面(mian)的原子與非(fei)(fei)電解質中的氧(yang)化(hua)劑直(zhi)接發生(sheng)(sheng)氧(yang)化(hua)還原反(fan)應,腐(fu)(fu)(fu)(fu)(fu)蝕(shi)產物生(sheng)(sheng)成(cheng)于(yu)發生(sheng)(sheng)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)反(fan)應的表面(mian),當(dang)它較牢固地(di)覆蓋在材(cai)(cai)料表面(mian)時(shi),會減緩腐(fu)(fu)(fu)(fu)(fu)蝕(shi)的進一步發生(sheng)(sheng)。腐(fu)(fu)(fu)(fu)(fu)蝕(shi)反(fan)應過程(cheng)中無電流產生(sheng)(sheng)。

  金(jin)屬和電解質接觸時(shi),由于(yu)(yu)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)電池(chi)作(zuo)用而(er)(er)引(yin)起的金(jin)屬腐(fu)(fu)(fu)蝕(shi)(shi)(shi)現象稱(cheng)為(wei)電化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)。腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的特點在(zai)于(yu)(yu),腐(fu)(fu)(fu)蝕(shi)(shi)(shi)歷程(cheng)可(ke)分為(wei)兩個(ge)相對獨立的并同(tong)時(shi)進行的陽(yang)極(ji)(ji)和陰極(ji)(ji)過程(cheng)。特征(zheng)為(wei)受蝕(shi)(shi)(shi)區(qu)(qu)是(shi)金(jin)屬表(biao)面的陽(yang)極(ji)(ji),腐(fu)(fu)(fu)蝕(shi)(shi)(shi)產物常(chang)常(chang)產生(sheng)(sheng)在(zai)陽(yang)極(ji)(ji)與陰極(ji)(ji)之間,不能覆(fu)蓋被蝕(shi)(shi)(shi)區(qu)(qu)域,通常(chang)起不到保護作(zuo)用。電化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)和化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的顯著區(qu)(qu)別是(shi)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)過程(cheng)中有電流產生(sheng)(sheng)。對于(yu)(yu)大(da)多(duo)(duo)數工業(ye)部門而(er)(er)言,發生(sheng)(sheng)電化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的情(qing)況遠多(duo)(duo)于(yu)(yu)發生(sheng)(sheng)化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)的情(qing)況。金(jin)屬發生(sheng)(sheng)高溫氧(yang)化(hua)(hua),表(biao)面生(sheng)(sheng)成一定厚度(du)的半導(dao)體(ti)性質的氧(yang)化(hua)(hua)膜,既可(ke)以(yi)傳導(dao)電子,也可(ke)以(yi)導(dao)通離子,此時(shi)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)不再是(shi)單純的化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi),而(er)(er)且還包含了電化(hua)(hua)學(xue)腐(fu)(fu)(fu)蝕(shi)(shi)(shi)。