福清熱鍍鋅的原理你知道嗎
福清熱鍍鋅也稱熱浸鍍鋅,是鋼鐵構件浸入熔融的鋅液中獲得金屬復蓋層的一種辦法。近年來隨高壓輸電、交通、通訊工作迅速發展,對鋼鐵件防護請求越來越高,熱鍍鋅需求量也不斷添加。
熱鍍鋅(xin)層防護功(gong)能(neng)
一般電(dian)(dian)鍍(du)(du)鋅(xin)(xin)層厚度5~15μm,而(er)熱鍍(du)(du)鋅(xin)(xin)層一般在(zai)35μm以上,乃(nai)至高達(da)200μm。熱鍍(du)(du)鋅(xin)(xin)復蓋才能好,鍍(du)(du)層細密,無有機物攙雜。盡人皆知,鋅(xin)(xin)的(de)抗(kang)大(da)(da)氣(qi)腐(fu)蝕的(de)機理有機械(xie)維(wei)(wei)護及電(dian)(dian)化(hua)學維(wei)(wei)護,在(zai)大(da)(da)氣(qi)腐(fu)蝕條件下鋅(xin)(xin)層外表有ZnO、Zn(OH)2及堿式(shi)碳酸鋅(xin)(xin)維(wei)(wei)護膜(mo),必(bi)定程度上減緩鋅(xin)(xin)的(de)腐(fu)蝕,這層維(wei)(wei)護膜(mo)(也稱白銹)遭到損壞又會(hui)構成新的(de)膜(mo)層。當鋅(xin)(xin)層損壞嚴峻(jun),危及到鐵(tie)(tie)(tie)基(ji)體(ti)(ti)時,鋅(xin)(xin)對基(ji)體(ti)(ti)發(fa)生電(dian)(dian)化(hua)學維(wei)(wei)護,鋅(xin)(xin)的(de)規范電(dian)(dian)位-0.76V,鐵(tie)(tie)(tie)的(de)規范電(dian)(dian)位-0.44V,鋅(xin)(xin)與鐵(tie)(tie)(tie)構成微電(dian)(dian)池(chi)時鋅(xin)(xin)作為陽極(ji)被溶(rong)解,鐵(tie)(tie)(tie)作為陰極(ji)遭到維(wei)(wei)護。顯(xian)然熱鍍(du)(du)鋅(xin)(xin)對基(ji)體(ti)(ti)金屬鐵(tie)(tie)(tie)的(de)抗(kang)大(da)(da)氣(qi)腐(fu)蝕才能優于電(dian)(dian)鍍(du)(du)鋅(xin)(xin)。
熱(re)(re)鍍(du)鋅(xin)層構成進程(cheng)熱(re)(re)鍍(du)鋅(xin)熱(re)(re)鍍(du)鋅(xin)
熱(re)鍍鋅(xin)(xin)(xin)(xin)層(ceng)(ceng)構(gou)成(cheng)(cheng)(cheng)進程(cheng)是(shi)鐵(tie)(tie)(tie)基(ji)體(ti)(ti)與(yu)外面的(de)純鋅(xin)(xin)(xin)(xin)層(ceng)(ceng)之間構(gou)成(cheng)(cheng)(cheng)鐵(tie)(tie)(tie)-鋅(xin)(xin)(xin)(xin)合金的(de)進程(cheng),工件(jian)(jian)外表在(zai)熱(re)浸鍍時(shi)構(gou)成(cheng)(cheng)(cheng)鐵(tie)(tie)(tie)-鋅(xin)(xin)(xin)(xin)合金層(ceng)(ceng),才(cai)使得(de)鐵(tie)(tie)(tie)與(yu)純鋅(xin)(xin)(xin)(xin)層(ceng)(ceng)之間很好結合,其(qi)進程(cheng)可簡略地敘說(shuo)為:當(dang)鐵(tie)(tie)(tie)工件(jian)(jian)浸入熔融(rong)的(de)鋅(xin)(xin)(xin)(xin)液(ye)時(shi),首(shou)先在(zai)界面上(shang)構(gou)成(cheng)(cheng)(cheng)鋅(xin)(xin)(xin)(xin)與(yu)α鐵(tie)(tie)(tie)(體(ti)(ti)心)固(gu)熔體(ti)(ti)。這是(shi)基(ji)體(ti)(ti)金屬鐵(tie)(tie)(tie)在(zai)固(gu)體(ti)(ti)狀態下溶有鋅(xin)(xin)(xin)(xin)原(yuan)(yuan)(yuan)子所構(gou)成(cheng)(cheng)(cheng)一種晶體(ti)(ti),兩(liang)種金屬原(yuan)(yuan)(yuan)子之間是(shi)交融(rong),原(yuan)(yuan)(yuan)子之間引力比較(jiao)小。因而(er),當(dang)鋅(xin)(xin)(xin)(xin)在(zai)固(gu)熔體(ti)(ti)中達到飽滿(man)后(hou),鋅(xin)(xin)(xin)(xin)鐵(tie)(tie)(tie)兩(liang)種元素原(yuan)(yuan)(yuan)子彼(bi)此(ci)分散,分散到(或叫進入)鐵(tie)(tie)(tie)基(ji)體(ti)(ti)中的(de)鋅(xin)(xin)(xin)(xin)原(yuan)(yuan)(yuan)子在(zai)基(ji)體(ti)(ti)晶格中遷移(yi),逐步(bu)與(yu)鐵(tie)(tie)(tie)構(gou)成(cheng)(cheng)(cheng)合金,而(er)分散到熔融(rong)的(de)鋅(xin)(xin)(xin)(xin)液(ye)中的(de)鐵(tie)(tie)(tie)就與(yu)鋅(xin)(xin)(xin)(xin)構(gou)成(cheng)(cheng)(cheng)金屬間化(hua)合物FeZn13,沉入熱(re)鍍鋅(xin)(xin)(xin)(xin)鍋(guo)底,即(ji)為鋅(xin)(xin)(xin)(xin)渣。當(dang)工件(jian)(jian)從浸鋅(xin)(xin)(xin)(xin)液(ye)中移(yi)出時(shi)外表構(gou)成(cheng)(cheng)(cheng)純鋅(xin)(xin)(xin)(xin)層(ceng)(ceng),為六方(fang)晶體(ti)(ti)。其(qi)含鐵(tie)(tie)(tie)量(liang)不(bu)大于0.003%
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