對黃銅脫鋅腐蝕的(de)(de)機(ji)理,國內外都做了一(yi)些研究,提出了各種研究結論,但目前還(huan)不(bu)十分(fen)完(wan)善,主要(yao)理論有優先溶解和溶解-再沉積機(ji)制(zhi)、雙空位機(ji)制(zhi)和滲流機(ji)制(zhi)。接下就讓我們來(lai)簡單的(de)(de)介紹一(yi)下這(zhe)些機(ji)制(zhi)。         

 1. 優(you)先溶解和溶解一再沉積機制，優先(xian)溶(rong)(rong)解(jie)機(ji)制認為(wei),黃(huang)銅(tong)(tong)(tong)腐(fu)蝕過(guo)程中,合金表面的鋅(xin)從黃(huang)銅(tong)(tong)(tong)中優先(xian)溶(rong)(rong)解(jie),然后(hou)合金內部的鋅(xin)通過(guo)空位(wei)擴散(san)繼續溶(rong)(rong)解(jie),電(dian)(dian)位(wei)較正的銅(tong)(tong)(tong)被遺留下(xia)來(lai),呈疏松狀的銅(tong)(tong)(tong)層。但這種理(li)論(lun)難以說明脫(tuo)(tuo)鋅(xin)造(zao)成的脆性(xing)(xing)開(kai)裂深度(du)與鋅(xin)在室溫下(xia)擴散(san)系數太低之間(jian)的矛盾(dun)。而(er)在黃(huang)銅(tong)(tong)(tong)表面與溶(rong)(rong)液接觸處發(fa)生了鋅(xin)選(xuan)擇性(xing)(xing)溶(rong)(rong)解(jie),被腐(fu)蝕的鋅(xin)由合金晶格上鋅(xin)原(yuan)子(zi)的擴散(san)所補(bu)償,鋅(xin)在活性(xing)(xing)脫(tuo)(tuo)鋅(xin)前沿(yan)被選(xuan)擇性(xing)(xing)侵蝕,這個前沿(yan)不斷(duan)地向內部移動。按照(zhao)作者的觀點,脫(tuo)(tuo)鋅(xin)相只是在初始(shi)黃(huang)銅(tong)(tong)(tong)母體的骨架結(jie)構中出現,它(ta)容許(xu)鋅(xin)離子(zi)自由向外(wai)擴散(san),黃(huang)銅(tong)(tong)(tong)的脫(tuo)(tuo)鋅(xin)阻力依賴于鋅(xin)外(wai)層電(dian)(dian)子(zi)離開(kai)鋅(xin)原(yuan)子(zi)的難易程度(du)。    

 2. 溶(rong)(rong)(rong)解(jie)(jie)-再沉積機制認為,黃銅(tong)(tong)(tong)表面上的(de)(de)(de)(de)(de)鋅(xin)(xin)和銅(tong)(tong)(tong)一(yi)起溶(rong)(rong)(rong)解(jie)(jie),鋅(xin)(xin)留在(zai)(zai)(zai)(zai)溶(rong)(rong)(rong)液中(zhong)，而(er)(er)銅(tong)(tong)(tong)在(zai)(zai)(zai)(zai)靠近溶(rong)(rong)(rong)解(jie)(jie)處(chu)的(de)(de)(de)(de)(de)表面上迅速析(xi)出而(er)(er)重新沉積在(zai)(zai)(zai)(zai)基體(ti)上,但這種機制無法(fa)圓滿地解(jie)(jie)釋銅(tong)(tong)(tong)不可能溶(rong)(rong)(rong)解(jie)(jie)時(shi)(shi)的(de)(de)(de)(de)(de)脫鋅(xin)(xin)現象(xiang)(xiang)。因(yin)為鋅(xin)(xin)溶(rong)(rong)(rong)解(jie)(jie)的(de)(de)(de)(de)(de)電(dian)(dian)位(wei)(wei)遠低(di)于(yu)銅(tong)(tong)(tong)的(de)(de)(de)(de)(de)陽極溶(rong)(rong)(rong)解(jie)(jie)電(dian)(dian)位(wei)(wei),因(yin)此(ci)(ci)銅(tong)(tong)(tong)和鋅(xin)(xin)不可能在(zai)(zai)(zai)(zai)任何情況下發(fa)生(sheng)同(tong)(tong)時(shi)(shi)溶(rong)(rong)(rong)解(jie)(jie)的(de)(de)(de)(de)(de)現象(xiang)(xiang)。在(zai)(zai)(zai)(zai)硫(liu)酸(suan)中(zhong)進(jin)行了(le)研究,在(zai)(zai)(zai)(zai)最初(chu)階(jie)段(duan)由于(yu)建立了(le)(Cu-Zn)原電(dian)(dian)池,鋅(xin)(xin)在(zai)(zai)(zai)(zai)溶(rong)(rong)(rong)液中(zhong)優先溶(rong)(rong)(rong)解(jie)(jie),但當(dang)多孔的(de)(de)(de)(de)(de)銅(tong)(tong)(tong)-氧化銅(tong)(tong)(tong)膜在(zai)(zai)(zai)(zai)電(dian)(dian)極表面形(xing)成時(shi)(shi),脫鋅(xin)(xin)速度(du)(du)下降(jiang),銅(tong)(tong)(tong)、鋅(xin)(xin)同(tong)(tong)時(shi)(shi)溶(rong)(rong)(rong)解(jie)(jie)。這時(shi)(shi)鋅(xin)(xin)的(de)(de)(de)(de)(de)溶(rong)(rong)(rong)解(jie)(jie)速度(du)(du)受(shou)通(tong)過晶格空位(wei)(wei)的(de)(de)(de)(de)(de)擴散速度(du)(du)所(suo)控制,在(zai)(zai)(zai)(zai)這個階(jie)段(duan)銅(tong)(tong)(tong)的(de)(de)(de)(de)(de)溶(rong)(rong)(rong)解(jie)(jie)速度(du)(du)因(yin)為CuO膜的(de)(de)(de)(de)(de)形(xing)成而(er)(er)減少,這決定性地位(wei)(wei)取決于(yu)腐蝕條件(jian),比如(ru)在(zai)(zai)(zai)(zai)稀鹽(yan)酸(suan)中(zhong)會發(fa)生(sheng)鋅(xin)(xin)的(de)(de)(de)(de)(de)選擇性溶(rong)(rong)(rong)解(jie)(jie),而(er)(er)在(zai)(zai)(zai)(zai)濃度(du)(du)較高的(de)(de)(de)(de)(de)鹽(yan)酸(suan)或海水中(zhong)則發(fa)生(sheng)銅(tong)(tong)(tong)重新析(xi)出的(de)(de)(de)(de)(de)脫鋅(xin)(xin)腐蝕。此(ci)(ci)外,脫鋅(xin)(xin)機制還受(shou)到溶(rong)(rong)(rong)解(jie)(jie)溫度(du)(du)、浸泡周期長短的(de)(de)(de)(de)(de)影響。銅(tong)(tong)(tong)和鋅(xin)(xin)是(shi)否同(tong)(tong)時(shi)(shi)溶(rong)(rong)(rong)解(jie)(jie),可以將它們(men)的(de)(de)(de)(de)(de)電(dian)(dian)位(wei)(wei)-pH圖重疊(die)后預測。        

 而防(fang)止黃(huang)(huang)銅(tong)(tong)脫鋅(xin)腐蝕(shi)(shi)的(de)(de)方(fang)法，主要(yao)可以從冶金(jin)方(fang)面入手,其(qi)次也可從改善環境方(fang)面考(kao)慮。改善腐蝕(shi)(shi)環境，則(ze)可以采用陰極保(bao)護、添加緩蝕(shi)(shi)劑、降低介(jie)質浸(jin)蝕(shi)(shi)性(xing)等,不過由于受(shou)工況(kuang)條件的(de)(de)限(xian)制,并不能完(wan)全抑制黃(huang)(huang)銅(tong)(tong)的(de)(de)脫鋅(xin)。根治的(de)(de)方(fang)法，則(ze)是通過冶金(jin)化方(fang)法提高(gao)黃(huang)(huang)銅(tong)(tong)自身的(de)(de)抗脫鋅(xin)能力,這(zhe)才是杜絕(jue)黃(huang)(huang)銅(tong)(tong)脫鋅(xin)腐蝕(shi)(shi)的(de)(de)發生絕(jue)對好(hao)方(fang)法。