1. 酸性錫電刷(shua)鍍液的性質
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(suan)性(xing)錫電刷鍍(du)層的性(xing)能與用(yong)途
酸性(xing)錫鍍液在低電(dian)壓(ya)下(xia)(xia)刷鍍所(suo)得的鍍層(ceng)光潔,呈(cheng)白灰色,電(dian)流小,效率低。在高(gao)電(dian)壓(ya)下(xia)(xia)刷鍍鍍層(ceng)逐漸變(bian)成淡灰色,電(dian)流增大,效率高(gao),表面結(jie)晶(jing)粗糙(cao)。
酸(suan)性(xing)錫經過電凈與(yu)活(huo)化(hua)后可直接刷(shua)鍍到不(bu)銹鋼上。主要用(yong)于防氮化(hua),以及劃傷和凹坑的填補,改善零件(jian)間的配合性(xing)能,提(ti)高磨(mo)合密封性(xing)。
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. 酸性錫電刷鍍液的配(pei)制
在1000mL燒杯(bei)中(zhong)(zhong)(zhong)(zhong),加(jia)(jia)(jia)蒸(zheng)(zheng)餾(liu)(liu)水600mL,加(jia)(jia)(jia)熱(re)(re)至(zhi)70℃,加(jia)(jia)(jia)入硫(liu)(liu)酸(suan)(suan)(suan)亞(ya)錫(xi)200g,維(wei)續加(jia)(jia)(jia)熱(re)(re)攪(jiao)(jiao)拌(ban)直至(zhi)完全溶(rong)(rong)(rong)解(jie)。在250mL燒杯(bei)中(zhong)(zhong)(zhong)(zhong)加(jia)(jia)(jia)蒸(zheng)(zheng)餾(liu)(liu)水100ml,加(jia)(jia)(jia)入氯化銨40g攪(jiao)(jiao)拌(ban)溶(rong)(rong)(rong)解(jie),加(jia)(jia)(jia)入硫(liu)(liu)酸(suan)(suan)(suan)亞(ya)錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong)(zhong),攪(jiao)(jiao)拌(ban)均勻,在250mL燒杯(bei)中(zhong)(zhong)(zhong)(zhong),加(jia)(jia)(jia)入蒸(zheng)(zheng)餾(liu)(liu)水100mL,加(jia)(jia)(jia)熱(re)(re)至(zhi)70℃,加(jia)(jia)(jia)入酒(jiu)石(shi)酸(suan)(suan)(suan)20g,草酸(suan)(suan)(suan)5g, 攪(jiao)(jiao)拌(ban)溶(rong)(rong)(rong)解(jie)后(hou),加(jia)(jia)(jia)入硫(liu)(liu)酸(suan)(suan)(suan)亞(ya)錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong)(zhong),攪(jiao)(jiao)拌(ban)均勻。在另一個50mL燒杯(bei)中(zhong)(zhong)(zhong)(zhong),加(jia)(jia)(jia)入 β-萘酚1g , 加(jia)(jia)(jia)入甲醇數毫升,攪(jiao)(jiao)拌(ban)溶(rong)(rong)(rong)解(jie)后(hou),在攪(jiao)(jiao)拌(ban)下(xia)加(jia)(jia)(jia)入硫(liu)(liu)酸(suan)(suan)(suan)亞(ya)錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong)(zhong),用(yong)10% 稀硫(liu)(liu)酸(suan)(suan)(suan)調整(zheng)pH=1~1.5,將(jiang)整(zheng)個溶(rong)(rong)(rong)液倒入1000mL量簡或(huo)量瓶(ping)中(zhong)(zhong)(zhong)(zhong),加(jia)(jia)(jia)蒸(zheng)(zheng)餾(liu)(liu)水至(zhi)刻度。盛于(yu)塑料(liao)容器(qi)中(zhong)(zhong)(zhong)(zhong)保存。
5. 使用方法和工藝規(gui)范
工(gong)作溫度:10~60℃;
耗電(dian)系數(shu):0.07A·h/(d㎡·μm);
工作電(dian)壓(ya):6~15V(最佳8~10V),電(dian)壓(ya)高于(yu)15V,電(dian)流(liu)并無明顯增加,陽極包套中(zhong)的(de)鍍(du)液出現(xian)沸騰,鍍(du)層粗(cu)糙(cao);
陰陽(yang)極相對運動速率(lv):20~40m/min,如果相對運動速率(lv)過小,<10m/min,在其他條件(jian)正(zheng)常(chang)時,鍍(du)層厚度大(da)于(yu)0.2mm時呈黑褐色粗糙層,結合力極差,用(yong)手(shou)即可搓掉,鍍(du)層完全(quan)沒有延展(zhan)性,無實際使用(yong)價值,通常(chang)相對運動速率(lv)必須(xu)大(da)于(yu)20m/min;
鍍(du)(du)液(ye)循(xun)(xun)環(huan)使(shi)用(yong)(yong)周期:鍍(du)(du)液(ye)在循(xun)(xun)環(huan)使(shi)用(yong)(yong)過程中,當刷鍍(du)(du)液(ye)容積(ji)消耗到60%時,錫離子由130g/L降到55g/L,已有75%的錫被沉積(ji)出來,酸(suan)性錫刷鍍(du)(du)液(ye)屬空乏型鍍(du)(du)液(ye),沉積(ji)速(su)率(lv)由快(kuai)變慢,鍍(du)(du)液(ye)的pH基本穩定,建議停止使(shi)用(yong)(yong),應回收處理后再用(yong)(yong)。