1. 酸性錫(xi)電(dian)刷鍍液的性質


  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)性錫電刷鍍層的性能與用(yong)途


  酸性錫鍍(du)(du)(du)液在低電壓下刷鍍(du)(du)(du)所得(de)的鍍(du)(du)(du)層光潔,呈(cheng)白(bai)灰色(se)(se),電流小,效(xiao)(xiao)率低。在高電壓下刷鍍(du)(du)(du)鍍(du)(du)(du)層逐(zhu)漸(jian)變成淡灰色(se)(se),電流增大,效(xiao)(xiao)率高,表面(mian)結晶粗(cu)糙(cao)。


  酸性(xing)(xing)錫經過電凈與活化后可直(zhi)接刷鍍到不銹鋼上。主(zhu)要用于防氮化,以(yi)及劃傷(shang)和凹坑(keng)的填補,改(gai)善零(ling)件間的配(pei)合性(xing)(xing)能,提高磨合密(mi)封性(xing)(xing)。



3. 酸(suan)性錫電刷鍍液的成分(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. 酸性(xing)錫(xi)電刷鍍液的配(pei)制


  在(zai)(zai)1000mL燒杯中(zhong)(zhong)(zhong),加(jia)(jia)(jia)蒸(zheng)(zheng)餾水600mL,加(jia)(jia)(jia)熱(re)(re)至(zhi)70℃,加(jia)(jia)(jia)入(ru)硫(liu)酸(suan)(suan)亞錫(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。在(zai)(zai)250mL燒杯中(zhong)(zhong)(zhong)加(jia)(jia)(jia)蒸(zheng)(zheng)餾水100ml,加(jia)(jia)(jia)入(ru)氯化銨40g攪(jiao)(jiao)拌(ban)溶(rong)(rong)(rong)解,加(jia)(jia)(jia)入(ru)硫(liu)酸(suan)(suan)亞錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong),攪(jiao)(jiao)拌(ban)均勻,在(zai)(zai)250mL燒杯中(zhong)(zhong)(zhong),加(jia)(jia)(jia)入(ru)蒸(zheng)(zheng)餾水100mL,加(jia)(jia)(jia)熱(re)(re)至(zhi)70℃,加(jia)(jia)(jia)入(ru)酒石酸(suan)(suan)20g,草酸(suan)(suan)5g, 攪(jiao)(jiao)拌(ban)溶(rong)(rong)(rong)解后,加(jia)(jia)(jia)入(ru)硫(liu)酸(suan)(suan)亞錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong),攪(jiao)(jiao)拌(ban)均勻。在(zai)(zai)另一個50mL燒杯中(zhong)(zhong)(zhong),加(jia)(jia)(jia)入(ru) β-萘酚1g , 加(jia)(jia)(jia)入(ru)甲醇數毫升,攪(jiao)(jiao)拌(ban)溶(rong)(rong)(rong)解后,在(zai)(zai)攪(jiao)(jiao)拌(ban)下加(jia)(jia)(jia)入(ru)硫(liu)酸(suan)(suan)亞錫(xi)溶(rong)(rong)(rong)液中(zhong)(zhong)(zhong),用(yong)10% 稀硫(liu)酸(suan)(suan)調整pH=1~1.5,將整個溶(rong)(rong)(rong)液倒入(ru)1000mL量簡或量瓶中(zhong)(zhong)(zhong),加(jia)(jia)(jia)蒸(zheng)(zheng)餾水至(zhi)刻(ke)度。盛于塑(su)料容(rong)器中(zhong)(zhong)(zhong)保存。



5. 使(shi)用(yong)方法(fa)和工藝規范


工作溫(wen)度:10~60℃;


耗電系數:0.07A·h/(d㎡·μm);


工作(zuo)電壓:6~15V(最佳8~10V),電壓高于15V,電流并無明顯增加(jia),陽極包套中的(de)鍍(du)液(ye)出(chu)現沸騰,鍍(du)層粗糙;


陰(yin)陽極相對(dui)運(yun)動(dong)速(su)(su)率(lv):20~40m/min,如果相對(dui)運(yun)動(dong)速(su)(su)率(lv)過小(xiao),<10m/min,在(zai)其(qi)他條(tiao)件正常時,鍍層厚度大(da)(da)于(yu)0.2mm時呈黑褐色粗糙層,結合力(li)極差,用手(shou)即可搓掉,鍍層完全沒有延展性(xing),無實際使用價值,通常相對(dui)運(yun)動(dong)速(su)(su)率(lv)必須大(da)(da)于(yu)20m/min;


鍍液循環使用周期:鍍液在循環使用過程中,當(dang)刷(shua)鍍液容積(ji)(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)(ji)出(chu)來,酸性錫刷(shua)鍍液屬空乏(fa)型鍍液,沉積(ji)(ji)速率由快變慢,鍍液的pH基本穩定,建議停止使用,應(ying)回(hui)收處(chu)理后再用。