1. 酸性錫電刷鍍液(ye)的性質(zhi)
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)錫電刷鍍層的性(xing)能與用(yong)途(tu)
酸(suan)性錫鍍液在低電(dian)壓下刷鍍所得的鍍層光潔,呈白灰色(se),電(dian)流小(xiao),效率低。在高電(dian)壓下刷鍍鍍層逐漸變成淡灰色(se),電(dian)流增大,效率高,表面結晶粗糙。
酸(suan)性(xing)錫經過電凈與活化后可直接刷鍍到(dao)不(bu)銹鋼上。主要用于(yu)防(fang)氮化,以及劃傷和凹坑的填補,改善零(ling)件間的配合(he)性(xing)能,提高磨合(he)密(mi)封性(xing)。
3. 酸性(xing)錫電刷鍍液的成分(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)鍍液的配制
在(zai)(zai)1000mL燒杯(bei)中(zhong),加(jia)(jia)(jia)(jia)蒸(zheng)餾水600mL,加(jia)(jia)(jia)(jia)熱至70℃,加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)硫(liu)(liu)酸(suan)亞(ya)錫200g,維續(xu)加(jia)(jia)(jia)(jia)熱攪(jiao)(jiao)拌(ban)(ban)(ban)直至完全溶(rong)(rong)(rong)解。在(zai)(zai)250mL燒杯(bei)中(zhong)加(jia)(jia)(jia)(jia)蒸(zheng)餾水100ml,加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)氯化銨40g攪(jiao)(jiao)拌(ban)(ban)(ban)溶(rong)(rong)(rong)解,加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)硫(liu)(liu)酸(suan)亞(ya)錫溶(rong)(rong)(rong)液(ye)中(zhong),攪(jiao)(jiao)拌(ban)(ban)(ban)均勻,在(zai)(zai)250mL燒杯(bei)中(zhong),加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)蒸(zheng)餾水100mL,加(jia)(jia)(jia)(jia)熱至70℃,加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)酒(jiu)石酸(suan)20g,草酸(suan)5g, 攪(jiao)(jiao)拌(ban)(ban)(ban)溶(rong)(rong)(rong)解后,加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)硫(liu)(liu)酸(suan)亞(ya)錫溶(rong)(rong)(rong)液(ye)中(zhong),攪(jiao)(jiao)拌(ban)(ban)(ban)均勻。在(zai)(zai)另一個(ge)50mL燒杯(bei)中(zhong),加(jia)(jia)(jia)(jia)入(ru)(ru)(ru) β-萘酚1g , 加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)甲醇數毫升,攪(jiao)(jiao)拌(ban)(ban)(ban)溶(rong)(rong)(rong)解后,在(zai)(zai)攪(jiao)(jiao)拌(ban)(ban)(ban)下加(jia)(jia)(jia)(jia)入(ru)(ru)(ru)硫(liu)(liu)酸(suan)亞(ya)錫溶(rong)(rong)(rong)液(ye)中(zhong),用10% 稀硫(liu)(liu)酸(suan)調整pH=1~1.5,將整個(ge)溶(rong)(rong)(rong)液(ye)倒入(ru)(ru)(ru)1000mL量(liang)簡或量(liang)瓶中(zhong),加(jia)(jia)(jia)(jia)蒸(zheng)餾水至刻度(du)。盛于塑(su)料容器中(zhong)保存。
5. 使用(yong)方法和工藝規范
工作溫度:10~60℃;
耗(hao)電系數:0.07A·h/(d㎡·μm);
工作電(dian)壓:6~15V(最(zui)佳8~10V),電(dian)壓高(gao)于(yu)15V,電(dian)流并無明顯增加,陽極包套中(zhong)的鍍液出(chu)現(xian)沸騰(teng),鍍層粗糙;
陰陽極相對(dui)(dui)(dui)運(yun)動(dong)速(su)率:20~40m/min,如果相對(dui)(dui)(dui)運(yun)動(dong)速(su)率過小,<10m/min,在其他條件正常時,鍍層厚度大(da)于0.2mm時呈黑(hei)褐色粗糙層,結合力極差(cha),用手(shou)即可(ke)搓掉,鍍層完全(quan)沒有延展性,無實際使用價值,通(tong)常相對(dui)(dui)(dui)運(yun)動(dong)速(su)率必須大(da)于20m/min;
鍍液(ye)循(xun)環使用(yong)周期:鍍液(ye)在循(xun)環使用(yong)過程中(zhong),當(dang)刷鍍液(ye)容積(ji)消耗到60%時,錫(xi)離子由130g/L降到55g/L,已(yi)有75%的錫(xi)被沉積(ji)出來,酸性(xing)錫(xi)刷鍍液(ye)屬空乏型(xing)鍍液(ye),沉積(ji)速率(lv)由快變慢(man),鍍液(ye)的pH基本穩定,建議停(ting)止使用(yong),應回收(shou)處(chu)理后再(zai)用(yong)。