1. 不銹鋼工件在電化學拋光前必須徹底除油,并用去污粉擦洗,以免油污污染拋光槽液。


 2. 在使(shi)用過程(cheng)中需(xu)要經常測量電化(hua)(hua)學(xue)拋光(guang)液的(de)相(xiang)(xiang)對(dui)密(mi)度。如果(guo)相(xiang)(xiang)對(dui)密(mi)度小(xiao)于配(pei)方(fang)規定(ding)值(zhi)(zhi),表明(ming)電化(hua)(hua)學(xue)拋光(guang)液含(han)水(shui)過多,可用蒸(zheng)發法將(jiang)溶(rong)(rong)液加熱(re)至80℃以上,將(jiang)多余水(shui)分(fen)除去,體積不足(zu)部分(fen)可按配(pei)方(fang)比例(li)補充磷酸和(he)硫(liu)酸。在工(gong)(gong)件(jian)進入(ru)電化(hua)(hua)學(xue)拋光(guang)槽前,最好(hao)將(jiang)工(gong)(gong)件(jian)上所附著的(de)水(shui)分(fen)瀝干或吹(chui)干。如果(guo)相(xiang)(xiang)對(dui)密(mi)度太高(gao),超過配(pei)方(fang)規定(ding)值(zhi)(zhi),表示水(shui)分(fen)過少(shao),要適當(dang)補充少(shao)量水(shui),使(shi)相(xiang)(xiang)對(dui)密(mi)度降至規定(ding)值(zhi)(zhi)。有(you)條件(jian)的(de)最好(hao)按周(zhou)期化(hua)(hua)驗分(fen)析溶(rong)(rong)液,根據結果(guo)及時進行調整。


3. 溶液的老化


  由于拋光過程中不銹鋼表面的溶解,溶液中的鐵、鎳、鉻含量將逐漸升高,此時溶液逐漸失去拋光能力。無論如何增高溫度,開大電流,均無助于恢復拋光能力。分析溶液,如鐵含量超過60g/L,三價鉻含量超過25g/L,說明溶液已經老化,在高濃度磷酸的存在下,鐵、鉻(三價)均呈酸式磷酸二氫鐵[Fe(H2PO4)3]或磷酸二氫鉻[Cr(H2PO4)3]形式存在,不易沉淀,只有當形成磷酸鐵(FePO4)或磷酸鉻(CrPO4)時才會沉淀于槽底。磷酸濃度較低的溶液具有自凈化能力。對于拋光溶液再生,恢復拋光能力,有兩種方法可供選擇。一個方法是適當用水稀釋溶液,降低酸度,鐵、鉻、鎳等雜質可局部呈磷酸鹽沉淀,除去槽底沉淀,然后再加熱蒸發除去水分,恢復原有的相對密度,此法操作起來較繁瑣,需要消耗較大的能源和時間。另一方法是更換部分溶液,最好保留20%的舊溶液,補充80%的新溶液。可以少通電或不通電處理,很快即可實現正常拋光。


4. 清理陰極鉛(qian)板(ban)


 在拋光(guang)過程中陰極(ji)鉛板(ban)表面會(hui)沉積出一層厚(hou)厚(hou)的鐵、鎳等雜質(zhi),影響陰極(ji)表面導(dao)(dao)電(dian),導(dao)(dao)致電(dian)流下降,使(shi)拋光(guang)表面的陽極(ji)電(dian)流密(mi)度也上不去(qu),嚴重影響拋光(guang)質(zhi)量。因此,要(yao)(yao)及時將陰極(ji)板(ban)上的沉積物除(chu)(chu)去(qu),有時形成(cheng)硬質(zhi)厚(hou)膜,要(yao)(yao)強力(li)敲打才能(neng)除(chu)(chu)下,最(zui)后沖洗干凈,以保持(chi)整個電(dian)路通暢。


5. 陰(yin)極與陽(yang)極面(mian)積比(bi)


 陰極面(mian)積控制在(zai)陽極面(mian)積的1/2~1/3.5.在(zai)此情況下,可以防止三價鉻的增長,過多的三價鉻在(zai)陽極表面(mian)被氧化成六價鉻。三價鉻含量過多,易使(shi)拋光液老化。


6. 陰陽極之(zhi)間的極距


 陰極(ji)與(yu)陽極(ji)之間的距離(li)過大(da)、電(dian)阻增大(da),電(dian)能消耗增大(da),溶液容易升溫,影(ying)響拋光質量。距離(li)過小(xiao),易造成短路打火,燒黑制品。陰極(ji)與(yu)陽極(ji)之間的距離(li)以100~300mm為宜。


7. 象形(xing)陰極


 對拋光一些復雜的(de)大型工(gong)件(jian),可制作(zuo)象(xiang)形陰極,以保持陽(yang)極電流分布(bu)均(jun)勻,特別是對內(nei)腔(qiang)工(gong)件(jian),有適(shi)當的(de)象(xiang)形陰極安置在內(nei)腔(qiang)中,才能(neng)使內(nei)腔(qiang)各部位拋光一致。


8. 進(jin)出(chu)槽要(yao)切斷(duan)電源


 在(zai)電(dian)(dian)化學拋光時,由于電(dian)(dian)流密(mi)度(du)較(jiao)高,給(gei)電(dian)(dian)流較(jiao)大,因(yin)此(ci),工件在(zai)進出拋光槽時,要先切斷(duan)電(dian)(dian)源(yuan),不(bu)可帶(dai)電(dian)(dian)掛或摘夾(jia)具,以防止產(chan)生(sheng)(sheng)電(dian)(dian)火花(hua),引起電(dian)(dian)解(jie)產(chan)生(sheng)(sheng),并(bing)會(hui)使聚集在(zai)槽面上(shang)的氫(qing)氣和(he)氧氣混合氣發生(sheng)(sheng)爆炸。


9. 控制槽液溫度


 由于強大的電流通過槽液,會使槽液升溫,在連續操作中要采取冷卻措施,使用冷凍機冷卻不斷升溫的槽液。拋光液的溫應適度維持在規定的工藝范圍內,使不銹鋼表面拋光整平速率維持正常,以便有效降低電解液的黏度,減少陽極黏膜的厚度,加速陽極溶解產物的擴散,使溶液對流加快,有利于陽極上滯留氣泡脫附,避免產生斑點、麻點。溫度過高,會導致溶液過熱,加速六價鉻向三價鉻的轉變(Cr6++3e→Cr3+),易產生表面腐蝕。溫度過低,使溶液黏度增大,陽極表面黏膜增厚,不利于陽極溶解物的擴散,使拋光整平效果明顯降低。


10. 控(kong)制合適(shi)的(de)陽極(ji)電(dian)流(liu)密(mi)度(du)


  不銹鋼零件(jian)電(dian)(dian)(dian)(dian)化學拋(pao)(pao)(pao)光(guang)(guang)(guang)時,陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度與(yu)金(jin)屬的(de)溶(rong)解(jie)幾乎(hu)呈(cheng)(cheng)正比。只有(you)選擇好陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度,并控制在一(yi)定(ding)(ding)的(de)陽(yang)(yang)極電(dian)(dian)(dian)(dian)位區間,才(cai)能獲得(de)良(liang)好的(de)電(dian)(dian)(dian)(dian)化學拋(pao)(pao)(pao)光(guang)(guang)(guang)質量,陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度的(de)最佳值(zhi),要(yao)根據不同的(de)電(dian)(dian)(dian)(dian)解(jie)液配方,通過(guo)實際拋(pao)(pao)(pao)光(guang)(guang)(guang),觀察(cha)拋(pao)(pao)(pao)光(guang)(guang)(guang)所得(de)最佳值(zhi)確定(ding)(ding)。在合(he)適的(de)陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度下,根據黏膜(mo)理論(lun),微觀表(biao)(biao)面凸出部位優先溶(rong)解(jie),有(you)利于整平精飾表(biao)(biao)面。陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度過(guo)小,零件(jian)表(biao)(biao)面發生(sheng)一(yi)般的(de)陽(yang)(yang)極溶(rong)解(jie),起(qi)不到拋(pao)(pao)(pao)光(guang)(guang)(guang)效(xiao)果。陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度過(guo)大,黏膜(mo)被擊穿,氧氣猛(meng)烈(lie)析出呈(cheng)(cheng)氣流(liu)狀,表(biao)(biao)面過(guo)熱(re),導致電(dian)(dian)(dian)(dian)拋(pao)(pao)(pao)光(guang)(guang)(guang)液擴散(san)加劇,黏膜(mo)被破壞,不復存在,發生(sheng)電(dian)(dian)(dian)(dian)化學腐(fu)蝕。所以(yi)在電(dian)(dian)(dian)(dian)拋(pao)(pao)(pao)光(guang)(guang)(guang)過(guo)程中(zhong)必須控制陽(yang)(yang)極電(dian)(dian)(dian)(dian)流(liu)密(mi)(mi)度在最佳值(zhi),也就是在確定(ding)(ding)的(de)工藝范(fan)圍(wei)內。


11. 陽極移動


 陽(yang)極(ji)(ji)(ji)移動(dong)使陽(yang)極(ji)(ji)(ji)溶解(jie)產(chan)物加快擴散出去(qu),起到攪拌作用,有效地(di)排除陽(yang)極(ji)(ji)(ji)表面滯留(liu)的(de)氣(qi)泡(pao),避免(mian)產(chan)生的(de)氣(qi)流(liu)生成條紋,防止(zhi)局部(bu)過熱造成表面過腐蝕。陽(yang)極(ji)(ji)(ji)移動(dong)有助于提高陽(yang)極(ji)(ji)(ji)電流(liu)密(mi)度(du),提高不(bu)銹鋼零件的(de)電化(hua)學拋光表面質量。


12. 氯離子的危害


 在(zai)電(dian)(dian)化(hua)學(xue)拋光(guang)液(ye)中(zhong)(zhong)不允許有活性氯(lv)離(li)(li)子(zi)存在(zai),氯(lv)離(li)(li)子(zi)能破壞電(dian)(dian)化(hua)學(xue)拋光(guang)中(zhong)(zhong)表面形成的保護(hu)性黏膜,使(shi)不銹鋼(gang)表面形成過腐蝕(shi)性的麻點。氯(lv)離(li)(li)子(zi)可(ke)在(zai)陽極高(gao)電(dian)(dian)流(liu)密度上氧化(hua)成氯(lv)氣逸出而除去。氯(lv)離(li)(li)子(zi)的來(lai)源可(ke)能是(shi)用鹽酸酸洗后未洗凈而帶入(ru)槽(cao)液(ye),或原料(liao)中(zhong)(zhong)的不純物氯(lv)離(li)(li)子(zi)引(yin)入(ru)。


13. 六價鉻和三價鉻的最佳配比


 在(zai)電(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學(xue)(xue)拋(pao)(pao)(pao)光(guang)(guang)液(ye)(ye)(ye)中(zhong)(zhong)(zhong)六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)有(you)(you)(you)氧化(hua)(hua)性,對(dui)不銹鋼(gang)表面(mian)起鈍(dun)化(hua)(hua)保(bao)護(hu)作(zuo)用,三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)對(dui)維護(hu)電(dian)(dian)(dian)(dian)(dian)拋(pao)(pao)(pao)光(guang)(guang)有(you)(you)(you)作(zuo)用。新配(pei)成(cheng)(cheng)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)拋(pao)(pao)(pao)光(guang)(guang)液(ye)(ye)(ye)如果沒(mei)有(you)(you)(you)化(hua)(hua)學(xue)(xue)反(fan)應(ying)產生三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge),還(huan)不能(neng)(neng)獲(huo)得良好(hao)(hao)的(de)(de)(de)拋(pao)(pao)(pao)光(guang)(guang)表面(mian)。只有(you)(you)(you)當電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)到溶(rong)(rong)(rong)(rong)液(ye)(ye)(ye)中(zhong)(zhong)(zhong)有(you)(you)(you)一(yi)定量(liang)(liang)(liang)的(de)(de)(de)三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)存在(zai)時(shi),才能(neng)(neng)出現理(li)想的(de)(de)(de)拋(pao)(pao)(pao)光(guang)(guang)表面(mian)。如果配(pei)方中(zhong)(zhong)(zhong)加有(you)(you)(you)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)酐(gan)(gan),即六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge),通(tong)過電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)反(fan)應(ying),在(zai)陰極上產生氫氣還(huan)原(yuan)部(bu)分(fen)(fen)六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)成(cheng)(cheng)為三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge);如果配(pei)方中(zhong)(zhong)(zhong)沒(mei)有(you)(you)(you)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)酐(gan)(gan),則三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)要靠陽(yang)極溶(rong)(rong)(rong)(rong)解(jie)(jie)(jie)不銹鋼(gang)所含(han)(han)(han)的(de)(de)(de)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)而得。這就(jiu)(jiu)是(shi)為什么(me)新配(pei)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)拋(pao)(pao)(pao)光(guang)(guang)液(ye)(ye)(ye)要充分(fen)(fen)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)后才能(neng)(neng)進(jin)行正常的(de)(de)(de)拋(pao)(pao)(pao)光(guang)(guang)工作(zuo)。在(zai)含(han)(han)(han)有(you)(you)(you)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)酐(gan)(gan)的(de)(de)(de)溶(rong)(rong)(rong)(rong)液(ye)(ye)(ye)中(zhong)(zhong)(zhong),加入明(ming)(ming)膠或(huo)甘油,它們能(neng)(neng)和(he)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)酐(gan)(gan)起強(qiang)烈(lie)的(de)(de)(de)還(huan)原(yuan)反(fan)應(ying),部(bu)分(fen)(fen)六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)轉變為三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)(Cr3+)。六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)是(shi)黃色(se)(se)(se)的(de)(de)(de),三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)是(shi)綠色(se)(se)(se)的(de)(de)(de)。它們在(zai)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)液(ye)(ye)(ye)中(zhong)(zhong)(zhong)使(shi)溶(rong)(rong)(rong)(rong)液(ye)(ye)(ye)呈(cheng)黃綠色(se)(se)(se)。這就(jiu)(jiu)是(shi)為什么(me)通(tong)電(dian)(dian)(dian)(dian)(dian)處理(li)后才可(ke)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)拋(pao)(pao)(pao)光(guang)(guang)。最佳(jia)的(de)(de)(de)拋(pao)(pao)(pao)光(guang)(guang)質量(liang)(liang)(liang)是(shi)在(zai)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)過程的(de)(de)(de)中(zhong)(zhong)(zhong)間階(jie)段。在(zai)生產過程中(zhong)(zhong)(zhong)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)拋(pao)(pao)(pao)光(guang)(guang)液(ye)(ye)(ye)要保(bao)持黃綠色(se)(se)(se)。此時(shi),根據(ju)化(hua)(hua)學(xue)(xue)分(fen)(fen)析數(shu)據(ju),六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)與三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)的(de)(de)(de)配(pei)比是(shi):含(han)(han)(han)Cr6+30%,含(han)(han)(han)Cr3+70%.為了維持該配(pei)比,可(ke)觀(guan)察電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)液(ye)(ye)(ye)的(de)(de)(de)顏色(se)(se)(se),如果顏色(se)(se)(se)呈(cheng)黃色(se)(se)(se)為主,表明(ming)(ming)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)液(ye)(ye)(ye)含(han)(han)(han)Cr6+偏高(gao),可(ke)加入適量(liang)(liang)(liang)的(de)(de)(de)明(ming)(ming)膠或(huo)甘油,使(shi)其部(bu)分(fen)(fen)六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)還(huan)原(yuan)為三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge),或(huo)通(tong)過大陰極小陽(yang)極電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)產生三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)。如果顏色(se)(se)(se)呈(cheng)深(shen)綠色(se)(se)(se),表明(ming)(ming)電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)液(ye)(ye)(ye)含(han)(han)(han)Cr3+高(gao)了,按比例適量(liang)(liang)(liang)加入用水溶(rong)(rong)(rong)(rong)解(jie)(jie)(jie)好(hao)(hao)的(de)(de)(de)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)酐(gan)(gan)溶(rong)(rong)(rong)(rong)液(ye)(ye)(ye),或(huo)通(tong)過大陽(yang)極小陰極電(dian)(dian)(dian)(dian)(dian)解(jie)(jie)(jie)拋(pao)(pao)(pao)光(guang)(guang)液(ye)(ye)(ye),使(shi)三(san)(san)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)部(bu)分(fen)(fen)轉變成(cheng)(cheng)六(liu)(liu)(liu)價(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(ge)(ge)(ge)。同時(shi)可(ke)改善溶(rong)(rong)(rong)(rong)液(ye)(ye)(ye)的(de)(de)(de)拋(pao)(pao)(pao)光(guang)(guang)質量(liang)(liang)(liang)。


14. 金屬拋除量


 如果(guo)電(dian)解拋(pao)光時(shi)陽(yang)極電(dian)流(liu)密(mi)度為(wei)20A/d㎡,時(shi)間(jian)為(wei)4min時(shi),用工(gong)具金相顯微(wei)鏡觀測,不(bu)銹鋼(gang)零件(jian)的(de)(de)(de)螺(luo)紋內徑的(de)(de)(de)金屬拋(pao)除(chu)量(liang)為(wei)每分鐘約0.001mm,螺(luo)紋外(wai)徑的(de)(de)(de)金屬拋(pao)除(chu)量(liang)為(wei)0.002mm,齒(chi)形(xing)基本(ben)無變化,僅齒(chi)的(de)(de)(de)頂部略有(you)拋(pao)鈍(dun)。陽(yang)極電(dian)流(liu)密(mi)度增(zeng)加,其金屬拋(pao)除(chu)量(liang)呈比例增(zeng)大。對于精密(mi)尺寸的(de)(de)(de)不(bu)銹鋼(gang)零件(jian)的(de)(de)(de)尺寸應考慮電(dian)化學拋(pao)光后(hou)的(de)(de)(de)金屬拋(pao)除(chu)量(liang)(損耗)。


15. 電焊或熱(re)處理后零件的(de)電化學拋光(guang)


 凡電焊(han)(han)或(huo)熱處(chu)理后(hou)的(de)零件在電化學拋光時(shi)按兩(liang)次進(jin)(jin)行,第(di)一次進(jin)(jin)槽(cao)拋光3~5min后(hou)取(qu)出,將(jiang)已疏松了的(de)焊(han)(han)渣(zha)和熱處(chu)理氧化皮用(yong)金屬絲(si)刷(shua)將(jiang)它刷(shua)掉(diao),或(huo)用(yong)小錘(chui)敲掉(diao),再第(di)二次進(jin)(jin)槽(cao)再拋光3~5min,可獲得較好的(de)效果。


16. 中(zhong)和工序


 經過(guo)電化(hua)學(xue)拋光(guang)后(hou)(hou)的(de)(de)零件(jian)(jian),如(ru)果不再進行后(hou)(hou)續加工,如(ru)電鍍、著色等其(qi)他工序,要進行鈍化(hua)和(he)中(zhong)和(he)。中(zhong)和(he)的(de)(de)作用(yong)是充分地(di)消除(chu)在電化(hua)學(xue)拋光(guang)和(he)鈍化(hua)后(hou)(hou)表面所吸(xi)附(fu)的(de)(de)酸性物(wu)質。中(zhong)和(he)一般是在碳酸鈉(na)20~30g/L的(de)(de)溶液中(zhong)進行的(de)(de)。路云鶴認為(wei),經過(guo)電化(hua)學(xue)拋光(guang)后(hou)(hou)的(de)(de)零件(jian)(jian)表面有一層均勻的(de)(de)鈍化(hua)膜(mo),可(ke)不需(xu)要再進行鈍化(hua)處理。不銹(xiu)鋼零件(jian)(jian)電化(hua)學(xue)拋光(guang)后(hou)(hou),經過(guo)40℃的(de)(de)溫水(shui)清洗,再冷(leng)水(shui)清洗,中(zhong)和(he)并清洗后(hou)(hou)用(yong)壓縮空氣吹(chui)干(gan),才可(ke)以有效地(di)避免(mian)殘留酸液腐蝕(shi)拋光(guang)表面。