材料(liao)與周圍非電(dian)解質(zhi)之間發生純化學作(zuo)用而引起的(de)腐(fu)蝕(shi)損(sun)傷(shang)稱為化學腐(fu)蝕(shi)。其反應(ying)特點是材料(liao)表面(mian)的(de)原子與非電(dian)解質(zhi)中(zhong)的(de)氧化劑直接發生氧化還(huan)原反應(ying),腐(fu)蝕(shi)產物生成于發生腐(fu)蝕(shi)反應(ying)的(de)表面(mian),當它較牢固地覆蓋在材料(liao)表面(mian)時,會減緩(huan)腐(fu)蝕(shi)的(de)進一(yi)步(bu)發生。腐(fu)蝕(shi)反應(ying)過程中(zhong)無電(dian)流產生。

  金屬和(he)電(dian)(dian)(dian)解質接觸時(shi),由于腐(fu)蝕(shi)(shi)(shi)(shi)(shi)電(dian)(dian)(dian)池作用而(er)(er)(er)引起的(de)(de)金屬腐(fu)蝕(shi)(shi)(shi)(shi)(shi)現(xian)象(xiang)稱為(wei)(wei)電(dian)(dian)(dian)化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi)。腐(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)特點在(zai)于,腐(fu)蝕(shi)(shi)(shi)(shi)(shi)歷(li)程(cheng)可分為(wei)(wei)兩個相對(dui)獨立的(de)(de)并(bing)同(tong)時(shi)進(jin)行的(de)(de)陽(yang)極和(he)陰極過(guo)程(cheng)。特征(zheng)為(wei)(wei)受蝕(shi)(shi)(shi)(shi)(shi)區(qu)是金屬表面的(de)(de)陽(yang)極,腐(fu)蝕(shi)(shi)(shi)(shi)(shi)產物常常產生在(zai)陽(yang)極與陰極之間,不(bu)能覆蓋被蝕(shi)(shi)(shi)(shi)(shi)區(qu)域(yu),通常起不(bu)到(dao)保護(hu)作用。電(dian)(dian)(dian)化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi)和(he)化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)顯著區(qu)別(bie)是腐(fu)蝕(shi)(shi)(shi)(shi)(shi)過(guo)程(cheng)中有電(dian)(dian)(dian)流(liu)產生。對(dui)于大多數工業部門而(er)(er)(er)言,發生電(dian)(dian)(dian)化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)情況遠多于發生化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi)的(de)(de)情況。金屬發生高溫氧(yang)化(hua)(hua)(hua)(hua)(hua),表面生成(cheng)一(yi)定厚度的(de)(de)半(ban)導體性質的(de)(de)氧(yang)化(hua)(hua)(hua)(hua)(hua)膜,既可以傳導電(dian)(dian)(dian)子,也可以導通離子,此(ci)時(shi)腐(fu)蝕(shi)(shi)(shi)(shi)(shi)不(bu)再是單純(chun)的(de)(de)化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi),而(er)(er)(er)且還包含了電(dian)(dian)(dian)化(hua)(hua)(hua)(hua)(hua)學腐(fu)蝕(shi)(shi)(shi)(shi)(shi)。