對黃銅(tong)脫鋅腐(fu)蝕的機(ji)理,國(guo)內外(wai)都做(zuo)了一些研(yan)究(jiu),提出了各(ge)種研(yan)究(jiu)結論(lun),但(dan)目(mu)前還不十分完(wan)善,主要(yao)理論(lun)有優先溶(rong)解和(he)溶(rong)解-再沉積機(ji)制、雙空位(wei)機(ji)制和(he)滲流機(ji)制。接下(xia)就讓我們(men)來(lai)簡單的介(jie)紹(shao)一下(xia)這(zhe)些機(ji)制。         

 1. 優(you)先溶解和溶解一再(zai)沉積(ji)機制，優先溶(rong)(rong)解(jie)機制認為,黃(huang)銅腐蝕(shi)過程中(zhong)(zhong),合(he)(he)金表面的(de)(de)(de)鋅(xin)(xin)從(cong)黃(huang)銅中(zhong)(zhong)優先溶(rong)(rong)解(jie),然(ran)后合(he)(he)金內(nei)部(bu)的(de)(de)(de)鋅(xin)(xin)通過空位擴散繼續溶(rong)(rong)解(jie),電位較正的(de)(de)(de)銅被(bei)遺留下來,呈(cheng)疏松狀的(de)(de)(de)銅層(ceng)。但這種理論難(nan)以說明脫(tuo)鋅(xin)(xin)造成的(de)(de)(de)脆性(xing)開(kai)裂深(shen)度與(yu)鋅(xin)(xin)在(zai)室溫下擴散系數太低之間的(de)(de)(de)矛盾。而在(zai)黃(huang)銅表面與(yu)溶(rong)(rong)液接觸處發生了鋅(xin)(xin)選(xuan)擇性(xing)溶(rong)(rong)解(jie),被(bei)腐蝕(shi)的(de)(de)(de)鋅(xin)(xin)由合(he)(he)金晶(jing)格上鋅(xin)(xin)原(yuan)(yuan)子(zi)(zi)(zi)(zi)的(de)(de)(de)擴散所補償,鋅(xin)(xin)在(zai)活性(xing)脫(tuo)鋅(xin)(xin)前沿(yan)被(bei)選(xuan)擇性(xing)侵蝕(shi),這個前沿(yan)不斷(duan)地(di)向(xiang)內(nei)部(bu)移動。按照作者的(de)(de)(de)觀(guan)點,脫(tuo)鋅(xin)(xin)相只是(shi)在(zai)初始(shi)黃(huang)銅母體的(de)(de)(de)骨架結構中(zhong)(zhong)出(chu)現,它容許鋅(xin)(xin)離子(zi)(zi)(zi)(zi)自由向(xiang)外擴散,黃(huang)銅的(de)(de)(de)脫(tuo)鋅(xin)(xin)阻(zu)力依賴于鋅(xin)(xin)外層(ceng)電子(zi)(zi)(zi)(zi)離開(kai)鋅(xin)(xin)原(yuan)(yuan)子(zi)(zi)(zi)(zi)的(de)(de)(de)難(nan)易程度。    

 2. 溶(rong)解(jie)(jie)-再(zai)沉積機制(zhi)(zhi)認為,黃銅(tong)(tong)表(biao)(biao)(biao)面(mian)上(shang)的鋅(xin)和銅(tong)(tong)一起溶(rong)解(jie)(jie),鋅(xin)留在(zai)(zai)溶(rong)液中(zhong)(zhong)，而銅(tong)(tong)在(zai)(zai)靠近溶(rong)解(jie)(jie)處的表(biao)(biao)(biao)面(mian)上(shang)迅速析出而重新(xin)沉積在(zai)(zai)基(ji)體上(shang),但(dan)這(zhe)(zhe)種機制(zhi)(zhi)無法圓滿地解(jie)(jie)釋銅(tong)(tong)不(bu)可能溶(rong)解(jie)(jie)時(shi)的脫(tuo)(tuo)鋅(xin)現象(xiang)。因為鋅(xin)溶(rong)解(jie)(jie)的電(dian)(dian)位(wei)(wei)(wei)遠低于(yu)銅(tong)(tong)的陽(yang)極溶(rong)解(jie)(jie)電(dian)(dian)位(wei)(wei)(wei),因此銅(tong)(tong)和鋅(xin)不(bu)可能在(zai)(zai)任何情(qing)況(kuang)下(xia)發生(sheng)同(tong)時(shi)溶(rong)解(jie)(jie)的現象(xiang)。在(zai)(zai)硫酸(suan)(suan)中(zhong)(zhong)進行(xing)了研究(jiu),在(zai)(zai)最初(chu)階段(duan)(duan)由于(yu)建立(li)了(Cu-Zn)原電(dian)(dian)池,鋅(xin)在(zai)(zai)溶(rong)液中(zhong)(zhong)優先(xian)溶(rong)解(jie)(jie),但(dan)當多孔的銅(tong)(tong)-氧化銅(tong)(tong)膜(mo)在(zai)(zai)電(dian)(dian)極表(biao)(biao)(biao)面(mian)形成時(shi),脫(tuo)(tuo)鋅(xin)速度(du)下(xia)降,銅(tong)(tong)、鋅(xin)同(tong)時(shi)溶(rong)解(jie)(jie)。這(zhe)(zhe)時(shi)鋅(xin)的溶(rong)解(jie)(jie)速度(du)受通過晶(jing)格空位(wei)(wei)(wei)的擴散速度(du)所控(kong)制(zhi)(zhi),在(zai)(zai)這(zhe)(zhe)個階段(duan)(duan)銅(tong)(tong)的溶(rong)解(jie)(jie)速度(du)因為CuO膜(mo)的形成而減少,這(zhe)(zhe)決定性地位(wei)(wei)(wei)取決于(yu)腐蝕(shi)(shi)條件(jian),比如在(zai)(zai)稀鹽酸(suan)(suan)中(zhong)(zhong)會發生(sheng)鋅(xin)的選擇性溶(rong)解(jie)(jie),而在(zai)(zai)濃度(du)較高的鹽酸(suan)(suan)或海水中(zhong)(zhong)則發生(sheng)銅(tong)(tong)重新(xin)析出的脫(tuo)(tuo)鋅(xin)腐蝕(shi)(shi)。此外(wai),脫(tuo)(tuo)鋅(xin)機制(zhi)(zhi)還受到(dao)溶(rong)解(jie)(jie)溫度(du)、浸泡周期長短的影響。銅(tong)(tong)和鋅(xin)是(shi)否同(tong)時(shi)溶(rong)解(jie)(jie),可以(yi)將它(ta)們的電(dian)(dian)位(wei)(wei)(wei)-pH圖重疊后預測。        

 而防止黃銅(tong)脫鋅(xin)(xin)腐蝕的(de)方法(fa)，主要可(ke)(ke)以(yi)從(cong)冶金(jin)方面入手,其次(ci)也可(ke)(ke)從(cong)改善(shan)環境(jing)方面考慮。改善(shan)腐蝕環境(jing)，則可(ke)(ke)以(yi)采用(yong)陰極保(bao)護、添加緩蝕劑、降低介質浸蝕性等(deng),不過由(you)于受工(gong)況條(tiao)件(jian)的(de)限(xian)制,并不能完全抑制黃銅(tong)的(de)脫鋅(xin)(xin)。根治的(de)方法(fa)，則是(shi)通過冶金(jin)化方法(fa)提高黃銅(tong)自身的(de)抗脫鋅(xin)(xin)能力,這才是(shi)杜絕黃銅(tong)脫鋅(xin)(xin)腐蝕的(de)發生絕對好方法(fa)。