1. 酸性(xing)(xing)錫電刷鍍(du)液的性(xing)(xing)質
酸性錫電刷鍍液為無色透明溶液,呈酸性,錫離子含量130g/L,20℃時相對密度為1.25,電導率為3.18×10-1Ω-1·cm-1,冰點 -10℃.鍍液溫度高時,工作電流大,生產效率高,鍍液供應一定要充分,這樣可避免鍍層氧化,提高鍍層與基體的結合力。
2. 酸性(xing)錫電刷(shua)鍍層的性(xing)能與用途
酸(suan)性錫(xi)鍍(du)液在低電壓下刷鍍(du)所得的鍍(du)層光潔,呈白灰色(se)(se),電流(liu)小,效率低。在高電壓下刷鍍(du)鍍(du)層逐漸變成淡灰色(se)(se),電流(liu)增大,效率高,表面結晶粗(cu)糙。
酸性錫經(jing)過電(dian)凈與活化后可直接刷(shua)鍍到(dao)不銹鋼上。主要用于防(fang)氮(dan)化,以及劃傷和凹坑的(de)填補,改(gai)善零件間的(de)配(pei)合(he)性能(neng),提高磨合(he)密(mi)封性。
3. 酸性錫電刷(shua)鍍液(ye)的成分(fen)
硫酸亞錫(SnSO4) 200g/L 、 草酸(H2C2O4) 5g/L 、 pH 1~1.5
氟化銨(NH4F) 40g/L 、β-萘酚 1g/L 、酒石酸(H2C4H4O6) 20g/L
4. 酸(suan)性錫電刷(shua)鍍液(ye)的配制
在(zai)1000mL燒(shao)杯中(zhong)(zhong)(zhong)(zhong),加蒸(zheng)餾(liu)(liu)水600mL,加熱至(zhi)(zhi)70℃,加入(ru)(ru)硫(liu)酸(suan)亞(ya)錫(xi)200g,維續加熱攪(jiao)拌(ban)直至(zhi)(zhi)完全溶(rong)(rong)(rong)解。在(zai)250mL燒(shao)杯中(zhong)(zhong)(zhong)(zhong)加蒸(zheng)餾(liu)(liu)水100ml,加入(ru)(ru)氯化銨40g攪(jiao)拌(ban)溶(rong)(rong)(rong)解,加入(ru)(ru)硫(liu)酸(suan)亞(ya)錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong)(zhong),攪(jiao)拌(ban)均勻,在(zai)250mL燒(shao)杯中(zhong)(zhong)(zhong)(zhong),加入(ru)(ru)蒸(zheng)餾(liu)(liu)水100mL,加熱至(zhi)(zhi)70℃,加入(ru)(ru)酒石酸(suan)20g,草酸(suan)5g, 攪(jiao)拌(ban)溶(rong)(rong)(rong)解后,加入(ru)(ru)硫(liu)酸(suan)亞(ya)錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong)(zhong),攪(jiao)拌(ban)均勻。在(zai)另(ling)一個50mL燒(shao)杯中(zhong)(zhong)(zhong)(zhong),加入(ru)(ru) β-萘酚1g , 加入(ru)(ru)甲醇數毫升,攪(jiao)拌(ban)溶(rong)(rong)(rong)解后,在(zai)攪(jiao)拌(ban)下加入(ru)(ru)硫(liu)酸(suan)亞(ya)錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong)(zhong),用10% 稀硫(liu)酸(suan)調整pH=1~1.5,將整個溶(rong)(rong)(rong)液倒入(ru)(ru)1000mL量(liang)簡或量(liang)瓶中(zhong)(zhong)(zhong)(zhong),加蒸(zheng)餾(liu)(liu)水至(zhi)(zhi)刻度。盛于(yu)塑料容器中(zhong)(zhong)(zhong)(zhong)保存。
5. 使(shi)用方法和工藝(yi)規(gui)范
工作(zuo)溫度:10~60℃;
耗(hao)電(dian)系數:0.07A·h/(d㎡·μm);
工作電壓:6~15V(最佳8~10V),電壓高(gao)于15V,電流并無(wu)明顯增加,陽(yang)極包套中的鍍(du)液(ye)出現沸騰(teng),鍍(du)層粗糙;
陰(yin)陽極相對(dui)運(yun)動速率(lv):20~40m/min,如果相對(dui)運(yun)動速率(lv)過小,<10m/min,在其(qi)他條件正常時,鍍層(ceng)(ceng)厚度大于0.2mm時呈黑褐色(se)粗糙層(ceng)(ceng),結合(he)力(li)極差,用(yong)手即可(ke)搓掉,鍍層(ceng)(ceng)完全沒有(you)延展性,無實(shi)際(ji)使(shi)用(yong)價值(zhi),通常相對(dui)運(yun)動速率(lv)必須大于20m/min;
鍍(du)(du)液(ye)(ye)(ye)循(xun)環使(shi)用(yong)(yong)周(zhou)期:鍍(du)(du)液(ye)(ye)(ye)在循(xun)環使(shi)用(yong)(yong)過程(cheng)中,當刷鍍(du)(du)液(ye)(ye)(ye)容(rong)積消(xiao)耗到60%時,錫離(li)子由130g/L降到55g/L,已有75%的錫被(bei)沉(chen)積出(chu)來,酸性錫刷鍍(du)(du)液(ye)(ye)(ye)屬空乏型(xing)鍍(du)(du)液(ye)(ye)(ye),沉(chen)積速率由快變慢,鍍(du)(du)液(ye)(ye)(ye)的pH基本穩定(ding),建議停止使(shi)用(yong)(yong),應(ying)回收處理后再用(yong)(yong)。