對(dui)黃銅脫鋅腐蝕的機理(li),國內外都做了(le)一些研(yan)究,提(ti)出了(le)各(ge)種研(yan)究結論,但目前還(huan)不十分完(wan)善,主要理(li)論有優先(xian)溶解(jie)和溶解(jie)-再(zai)沉積機制、雙空位機制和滲流機制。接下就(jiu)讓我(wo)們(men)來簡(jian)單(dan)的介紹(shao)一下這些機制。         

 1. 優先溶解(jie)和溶解(jie)一再沉積機(ji)制(zhi)，優先(xian)溶解(jie)機制認為,黃(huang)(huang)銅(tong)腐蝕(shi)過程(cheng)中,合金表面的(de)(de)鋅(xin)(xin)從黃(huang)(huang)銅(tong)中優先(xian)溶解(jie),然后合金內部(bu)的(de)(de)鋅(xin)(xin)通過空位(wei)擴散繼續溶解(jie),電位(wei)較正的(de)(de)銅(tong)被遺留(liu)下(xia)來,呈(cheng)疏松狀的(de)(de)銅(tong)層。但(dan)這種(zhong)理論難以說明脫(tuo)鋅(xin)(xin)造(zao)成的(de)(de)脆(cui)性(xing)開裂深度與鋅(xin)(xin)在(zai)室溫下(xia)擴散系(xi)數太低之間的(de)(de)矛盾。而在(zai)黃(huang)(huang)銅(tong)表面與溶液(ye)接觸處發(fa)生了鋅(xin)(xin)選(xuan)擇性(xing)溶解(jie),被腐蝕(shi)的(de)(de)鋅(xin)(xin)由合金晶(jing)格(ge)上(shang)鋅(xin)(xin)原(yuan)子的(de)(de)擴散所補償,鋅(xin)(xin)在(zai)活性(xing)脫(tuo)鋅(xin)(xin)前沿被選(xuan)擇性(xing)侵蝕(shi),這個(ge)前沿不斷地向內部(bu)移動(dong)。按(an)照作者的(de)(de)觀點,脫(tuo)鋅(xin)(xin)相(xiang)只是在(zai)初始黃(huang)(huang)銅(tong)母(mu)體的(de)(de)骨架結構中出現,它(ta)容許鋅(xin)(xin)離子自由向外(wai)擴散,黃(huang)(huang)銅(tong)的(de)(de)脫(tuo)鋅(xin)(xin)阻(zu)力依(yi)賴(lai)于鋅(xin)(xin)外(wai)層電子離開鋅(xin)(xin)原(yuan)子的(de)(de)難易程(cheng)度。    

 2. 溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)-再沉積機(ji)制認(ren)為(wei),黃銅表面(mian)(mian)上的鋅(xin)(xin)(xin)(xin)和銅一起溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie),鋅(xin)(xin)(xin)(xin)留(liu)在(zai)(zai)(zai)(zai)溶(rong)(rong)(rong)(rong)(rong)液(ye)中，而(er)銅在(zai)(zai)(zai)(zai)靠近溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)處的表面(mian)(mian)上迅速(su)(su)析出而(er)重(zhong)新沉積在(zai)(zai)(zai)(zai)基體(ti)上,但這種機(ji)制無法圓滿(man)地解(jie)(jie)釋銅不可能(neng)溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)時(shi)的脫鋅(xin)(xin)(xin)(xin)現(xian)象(xiang)。因(yin)為(wei)鋅(xin)(xin)(xin)(xin)溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)的電位遠低(di)于銅的陽(yang)極溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)電位,因(yin)此(ci)銅和鋅(xin)(xin)(xin)(xin)不可能(neng)在(zai)(zai)(zai)(zai)任何情況下發生同(tong)時(shi)溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)的現(xian)象(xiang)。在(zai)(zai)(zai)(zai)硫酸中進(jin)行了(le)研究,在(zai)(zai)(zai)(zai)最初(chu)階段(duan)由于建(jian)立(li)了(le)(Cu-Zn)原電池,鋅(xin)(xin)(xin)(xin)在(zai)(zai)(zai)(zai)溶(rong)(rong)(rong)(rong)(rong)液(ye)中優(you)先溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie),但當(dang)多孔的銅-氧化銅膜在(zai)(zai)(zai)(zai)電極表面(mian)(mian)形成時(shi),脫鋅(xin)(xin)(xin)(xin)速(su)(su)度(du)(du)(du)下降,銅、鋅(xin)(xin)(xin)(xin)同(tong)時(shi)溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)。這時(shi)鋅(xin)(xin)(xin)(xin)的溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)速(su)(su)度(du)(du)(du)受通過晶格空位的擴散(san)速(su)(su)度(du)(du)(du)所控制,在(zai)(zai)(zai)(zai)這個階段(duan)銅的溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)速(su)(su)度(du)(du)(du)因(yin)為(wei)CuO膜的形成而(er)減(jian)少,這決定性地位取決于腐蝕(shi)(shi)條件,比(bi)如在(zai)(zai)(zai)(zai)稀鹽酸中會發生鋅(xin)(xin)(xin)(xin)的選擇性溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie),而(er)在(zai)(zai)(zai)(zai)濃度(du)(du)(du)較(jiao)高的鹽酸或海水(shui)中則(ze)發生銅重(zhong)新析出的脫鋅(xin)(xin)(xin)(xin)腐蝕(shi)(shi)。此(ci)外,脫鋅(xin)(xin)(xin)(xin)機(ji)制還受到溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie)溫度(du)(du)(du)、浸泡(pao)周期長短(duan)的影響。銅和鋅(xin)(xin)(xin)(xin)是否同(tong)時(shi)溶(rong)(rong)(rong)(rong)(rong)解(jie)(jie),可以將它們的電位-pH圖重(zhong)疊后(hou)預(yu)測。        

 而防(fang)止(zhi)黃銅(tong)脫(tuo)鋅腐(fu)(fu)蝕(shi)的方(fang)法，主要(yao)可(ke)以從冶金方(fang)面入手(shou),其(qi)次也(ye)可(ke)從改善(shan)環境方(fang)面考(kao)慮。改善(shan)腐(fu)(fu)蝕(shi)環境，則(ze)可(ke)以采用陰極保護(hu)、添加緩蝕(shi)劑、降低(di)介質浸蝕(shi)性等,不過由(you)于受工(gong)況條件的限(xian)制,并不能(neng)完(wan)全抑制黃銅(tong)的脫(tuo)鋅。根治的方(fang)法，則(ze)是通過冶金化(hua)方(fang)法提高黃銅(tong)自身的抗脫(tuo)鋅能(neng)力,這才是杜絕黃銅(tong)脫(tuo)鋅腐(fu)(fu)蝕(shi)的發(fa)生(sheng)絕對好方(fang)法。