材(cai)料與(yu)周圍非電解質之間發生(sheng)純化(hua)(hua)學(xue)作用而引起(qi)的腐(fu)(fu)蝕損(sun)傷稱(cheng)為化(hua)(hua)學(xue)腐(fu)(fu)蝕。其(qi)反(fan)(fan)(fan)應(ying)特點是材(cai)料表面的原(yuan)子與(yu)非電解質中的氧化(hua)(hua)劑直接發生(sheng)氧化(hua)(hua)還(huan)原(yuan)反(fan)(fan)(fan)應(ying),腐(fu)(fu)蝕產物生(sheng)成(cheng)于(yu)發生(sheng)腐(fu)(fu)蝕反(fan)(fan)(fan)應(ying)的表面,當它較牢固地覆蓋在材(cai)料表面時,會減緩腐(fu)(fu)蝕的進(jin)一(yi)步發生(sheng)。腐(fu)(fu)蝕反(fan)(fan)(fan)應(ying)過程中無電流產生(sheng)。

  金屬(shu)和(he)(he)電(dian)(dian)(dian)解質(zhi)接觸時,由于(yu)腐(fu)(fu)(fu)(fu)蝕(shi)(shi)電(dian)(dian)(dian)池作用(yong)而引起(qi)(qi)的(de)(de)金屬(shu)腐(fu)(fu)(fu)(fu)蝕(shi)(shi)現象稱為(wei)電(dian)(dian)(dian)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi)。腐(fu)(fu)(fu)(fu)蝕(shi)(shi)的(de)(de)特點在于(yu),腐(fu)(fu)(fu)(fu)蝕(shi)(shi)歷程可分為(wei)兩個相對獨立的(de)(de)并同時進(jin)行的(de)(de)陽(yang)極和(he)(he)陰(yin)極過程。特征為(wei)受(shou)蝕(shi)(shi)區是(shi)(shi)金屬(shu)表面的(de)(de)陽(yang)極,腐(fu)(fu)(fu)(fu)蝕(shi)(shi)產物常常產生(sheng)在陽(yang)極與陰(yin)極之(zhi)間,不能覆蓋被蝕(shi)(shi)區域,通常起(qi)(qi)不到保護(hu)作用(yong)。電(dian)(dian)(dian)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi)和(he)(he)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi)的(de)(de)顯著區別是(shi)(shi)腐(fu)(fu)(fu)(fu)蝕(shi)(shi)過程中(zhong)有電(dian)(dian)(dian)流產生(sheng)。對于(yu)大多數工(gong)業部門而言,發生(sheng)電(dian)(dian)(dian)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi)的(de)(de)情況遠多于(yu)發生(sheng)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi)的(de)(de)情況。金屬(shu)發生(sheng)高(gao)溫氧化,表面生(sheng)成一定(ding)厚(hou)度(du)的(de)(de)半導(dao)體(ti)性(xing)質(zhi)的(de)(de)氧化膜,既可以傳導(dao)電(dian)(dian)(dian)子(zi),也(ye)可以導(dao)通離子(zi),此時腐(fu)(fu)(fu)(fu)蝕(shi)(shi)不再是(shi)(shi)單純的(de)(de)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi),而且(qie)還(huan)包含了電(dian)(dian)(dian)化學腐(fu)(fu)(fu)(fu)蝕(shi)(shi)。