就是利用電解原理在某些金屬表面上鍍上一薄層其它金屬或合金的過程。電鍍時，鍍層金屬做陽極，被氧化成陽離子進入電鍍液；待鍍的金屬制品做陰極，鍍層金屬的陽離子在金屬表面被還原形成鍍層。為排除其它陽離子的干擾，且使鍍層均勻、牢固，需用含鍍層金屬陽離子的溶液做電鍍液，以保持鍍層金屬陽離子的濃度不變。電鍍的目的是在基材上鍍上金屬鍍層(deposit),改變基材表面性質或尺寸.電鍍能增強金屬的抗腐蝕性(鍍層金屬多采用耐腐蝕的金屬)、增加硬度、防止磨耗、提高導電性、潤滑性、耐熱性、和表面美觀。
電(dian)(dian)(dian)(dian)鍍(du)(du)需要一個(ge)向(xiang)電(dian)(dian)(dian)(dian)鍍(du)(du)槽(cao)供電(dian)(dian)(dian)(dian)的(de)(de)(de)(de)低(di)壓(ya)大電(dian)(dian)(dian)(dian)流電(dian)(dian)(dian)(dian)源以及由電(dian)(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)、待(dai)鍍(du)(du)零件(jian)(陰極(ji)(ji))和陽(yang)極(ji)(ji)構(gou)成(cheng)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)解裝置。其中電(dian)(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)成(cheng)分(fen)視鍍(du)(du)層不同(tong)而不同(tong)，但均含有提供金屬離子的(de)(de)(de)(de)主鹽(yan)(yan)，能絡合(he)主鹽(yan)(yan)中金屬離子形成(cheng)絡合(he)物的(de)(de)(de)(de)絡合(he)劑(ji)(ji)，用于穩定溶(rong)液(ye)(ye)酸堿度(du)的(de)(de)(de)(de)緩沖劑(ji)(ji)，陽(yang)極(ji)(ji)活化(hua)劑(ji)(ji)和特殊添加物(如光亮劑(ji)(ji)、晶粒細化(hua)劑(ji)(ji)、整平劑(ji)(ji)、潤(run)濕劑(ji)(ji)、應力消除劑(ji)(ji)和抑霧劑(ji)(ji)等)。電(dian)(dian)(dian)(dian)鍍(du)(du)過(guo)程是鍍(du)(du)液(ye)(ye)中的(de)(de)(de)(de)金屬離子在外電(dian)(dian)(dian)(dian)場的(de)(de)(de)(de)作用下，經電(dian)(dian)(dian)(dian)極(ji)(ji)反應還原(yuan)(yuan)成(cheng)金屬原(yuan)(yuan)子，并在陰極(ji)(ji)上(shang)進行(xing)金屬沉積的(de)(de)(de)(de)過(guo)程。因此，這是一個(ge)包括液(ye)(ye)相(xiang)傳質、電(dian)(dian)(dian)(dian)化(hua)學反應和電(dian)(dian)(dian)(dian)結晶等步驟的(de)(de)(de)(de)金屬電(dian)(dian)(dian)(dian)沉積過(guo)程。

在盛有(you)電(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)的(de)(de)(de)(de)(de)鍍(du)(du)槽中(zhong)，經過清(qing)理和特殊(shu)預(yu)處理的(de)(de)(de)(de)(de)待鍍(du)(du)件(jian)作為陰極(ji)(ji)，用(yong)(yong)鍍(du)(du)覆金屬(shu)(shu)(shu)制成(cheng)(cheng)陽極(ji)(ji)，兩(liang)極(ji)(ji)分(fen)別與直流電(dian)(dian)(dian)源(yuan)的(de)(de)(de)(de)(de)正極(ji)(ji)和負(fu)極(ji)(ji)聯接。電(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)由含有(you)鍍(du)(du)覆金屬(shu)(shu)(shu)的(de)(de)(de)(de)(de)化合物(wu)、導(dao)電(dian)(dian)(dian)的(de)(de)(de)(de)(de)鹽(yan)類、緩沖劑、pH調(diao)節劑和添加(jia)劑等(deng)的(de)(de)(de)(de)(de)水溶(rong)液(ye)(ye)(ye)組成(cheng)(cheng)。通電(dian)(dian)(dian)后，電(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)中(zhong)的(de)(de)(de)(de)(de)金屬(shu)(shu)(shu)離子(zi)，在電(dian)(dian)(dian)位(wei)差的(de)(de)(de)(de)(de)作用(yong)(yong)下(xia)移動到陰極(ji)(ji)上形成(cheng)(cheng)鍍(du)(du)層(ceng)。陽極(ji)(ji)的(de)(de)(de)(de)(de)金屬(shu)(shu)(shu)形成(cheng)(cheng)金屬(shu)(shu)(shu)離子(zi)進入(ru)電(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)，以保持(chi)被(bei)鍍(du)(du)覆的(de)(de)(de)(de)(de)金屬(shu)(shu)(shu)離子(zi)的(de)(de)(de)(de)(de)濃度(du)。在有(you)些情況下(xia)，如鍍(du)(du)鉻(ge)，是采用(yong)(yong)鉛、鉛銻合金制成(cheng)(cheng)的(de)(de)(de)(de)(de)不溶(rong)性(xing)陽極(ji)(ji)，它只起傳遞電(dian)(dian)(dian)子(zi)、導(dao)通電(dian)(dian)(dian)流的(de)(de)(de)(de)(de)作用(yong)(yong)。電(dian)(dian)(dian)解(jie)液(ye)(ye)(ye)中(zhong)的(de)(de)(de)(de)(de)鉻(ge)離子(zi)濃度(du)，需(xu)(xu)依靠定(ding)期(qi)地(di)向(xiang)鍍(du)(du)液(ye)(ye)(ye)中(zhong)加(jia)入(ru)鉻(ge)化合物(wu)來(lai)維持(chi)。電(dian)(dian)(dian)鍍(du)(du)時(shi)，陽極(ji)(ji)材(cai)料(liao)的(de)(de)(de)(de)(de)質量(liang)、電(dian)(dian)(dian)鍍(du)(du)液(ye)(ye)(ye)的(de)(de)(de)(de)(de)成(cheng)(cheng)分(fen)、溫度(du)、電(dian)(dian)(dian)流密度(du)、通電(dian)(dian)(dian)時(shi)間、攪拌(ban)強度(du)、析出的(de)(de)(de)(de)(de)雜(za)質、電(dian)(dian)(dian)源(yuan)波形等(deng)都(dou)會影響(xiang)鍍(du)(du)層(ceng)的(de)(de)(de)(de)(de)質量(liang)，需(xu)(xu)要適時(shi)進行控(kong)制。

首先電鍍(du)液有六個要素(su):主鹽、附加(jia)鹽、絡合(he)劑、緩沖(chong)劑、陽極活化(hua)劑和添加(jia)劑。

電(dian)鍍原理包含四個方(fang)面(mian):電(dian)鍍液、電(dian)鍍反應、電(dian)極與(yu)反應原理、金屬的電(dian)沉(chen)積(ji)過程。