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(guo)(guo)程中需要經常測(ce)量電(dian)化(hua)學(xue)(xue)拋(pao)光液(ye)(ye)的相(xiang)(xiang)對(dui)(dui)密(mi)(mi)(mi)度(du)。如果相(xiang)(xiang)對(dui)(dui)密(mi)(mi)(mi)度(du)小于(yu)配(pei)(pei)方規(gui)定值,表(biao)明電(dian)化(hua)學(xue)(xue)拋(pao)光液(ye)(ye)含水(shui)(shui)過(guo)(guo)多,可用蒸發法將溶液(ye)(ye)加(jia)熱至80℃以上(shang),將多余(yu)水(shui)(shui)分除去,體積不足部(bu)分可按配(pei)(pei)方比例補充(chong)磷酸(suan)和硫酸(suan)。在工(gong)件(jian)進入電(dian)化(hua)學(xue)(xue)拋(pao)光槽前(qian),最好將工(gong)件(jian)上(shang)所(suo)附(fu)著(zhu)的水(shui)(shui)分瀝(li)干或吹干。如果相(xiang)(xiang)對(dui)(dui)密(mi)(mi)(mi)度(du)太(tai)高,超(chao)過(guo)(guo)配(pei)(pei)方規(gui)定值,表(biao)示水(shui)(shui)分過(guo)(guo)少,要適當補充(chong)少量水(shui)(shui),使(shi)相(xiang)(xiang)對(dui)(dui)密(mi)(mi)(mi)度(du)降至規(gui)定值。有條件(jian)的最好按周期(qi)化(hua)驗分析溶液(ye)(ye),根(gen)據結果及(ji)時(shi)進行調整(zheng)。


3. 溶液的(de)老(lao)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(li)陰極鉛板


 在拋(pao)光過程中陰極(ji)鉛板(ban)表面(mian)(mian)(mian)會(hui)沉積出一層(ceng)厚(hou)厚(hou)的(de)鐵(tie)、鎳等雜質,影(ying)(ying)響(xiang)陰極(ji)表面(mian)(mian)(mian)導電(dian),導致電(dian)流下(xia)降,使拋(pao)光表面(mian)(mian)(mian)的(de)陽極(ji)電(dian)流密度也(ye)上不去(qu),嚴重影(ying)(ying)響(xiang)拋(pao)光質量。因此,要(yao)及時(shi)將陰極(ji)板(ban)上的(de)沉積物除去(qu),有時(shi)形成硬質厚(hou)膜,要(yao)強力敲(qiao)打才能(neng)除下(xia),最后沖(chong)洗干凈,以保持整個電(dian)路通暢(chang)。


5. 陰極與陽極面(mian)積比


 陰極(ji)面(mian)積(ji)控制(zhi)在陽(yang)極(ji)面(mian)積(ji)的1/2~1/3.5.在此情(qing)況下,可以(yi)防止(zhi)三價(jia)(jia)鉻的增長,過多(duo)的三價(jia)(jia)鉻在陽(yang)極(ji)表面(mian)被氧化成六價(jia)(jia)鉻。三價(jia)(jia)鉻含量過多(duo),易(yi)使拋光(guang)液老化。


6. 陰陽極(ji)之(zhi)間的極(ji)距(ju)


 陰極與(yu)陽極之間的距(ju)離過大、電阻增大,電能消耗(hao)增大,溶(rong)液容易升(sheng)溫(wen),影響拋光質量。距(ju)離過小(xiao),易造成短路打火,燒黑(hei)制(zhi)品。陰極與(yu)陽極之間的距(ju)離以(yi)100~300mm為宜。


7. 象形陰極


 對(dui)拋(pao)(pao)光一(yi)些復雜的(de)大型工件,可制作象(xiang)形陰極(ji)(ji),以保持陽極(ji)(ji)電流(liu)分布(bu)均勻,特別是對(dui)內腔(qiang)工件,有適當的(de)象(xiang)形陰極(ji)(ji)安置在內腔(qiang)中,才(cai)能使內腔(qiang)各部位拋(pao)(pao)光一(yi)致。


8. 進出槽(cao)要切斷電源(yuan)


 在(zai)電(dian)化學拋(pao)(pao)光時,由于電(dian)流密(mi)度較(jiao)高,給電(dian)流較(jiao)大,因此,工件在(zai)進出(chu)拋(pao)(pao)光槽時,要(yao)先切斷電(dian)源,不可帶(dai)電(dian)掛或摘夾(jia)具,以防止產生電(dian)火花,引(yin)起電(dian)解產生,并(bing)會使聚集在(zai)槽面(mian)上(shang)的氫(qing)氣(qi)和氧氣(qi)混(hun)合氣(qi)發生爆炸。


9. 控制槽液(ye)溫度(du)


 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. 控制(zhi)合適(shi)的(de)陽(yang)極電(dian)流密度


  不(bu)銹鋼零(ling)件(jian)電(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學(xue)(xue)拋(pao)光(guang)時(shi),陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度與金屬的(de)(de)(de)溶(rong)(rong)解幾(ji)乎(hu)呈正比(bi)。只有選(xuan)擇好陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度,并控制(zhi)在(zai)(zai)一定的(de)(de)(de)陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)位區間,才能獲得良好的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學(xue)(xue)拋(pao)光(guang)質量,陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度的(de)(de)(de)最佳(jia)值,要(yao)根據(ju)不(bu)同的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)解液配(pei)方(fang),通過(guo)實(shi)際(ji)拋(pao)光(guang),觀察拋(pao)光(guang)所得最佳(jia)值確(que)定。在(zai)(zai)合(he)適的(de)(de)(de)陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度下,根據(ju)黏(nian)膜理論,微觀表(biao)(biao)面凸出部位優先溶(rong)(rong)解,有利于整平精飾表(biao)(biao)面。陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度過(guo)小,零(ling)件(jian)表(biao)(biao)面發(fa)生(sheng)一般的(de)(de)(de)陽(yang)(yang)極(ji)(ji)(ji)溶(rong)(rong)解,起不(bu)到拋(pao)光(guang)效果。陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度過(guo)大,黏(nian)膜被(bei)擊穿,氧氣猛(meng)烈(lie)析出呈氣流(liu)(liu)(liu)狀(zhuang),表(biao)(biao)面過(guo)熱,導(dao)致電(dian)(dian)(dian)(dian)(dian)(dian)拋(pao)光(guang)液擴散加劇,黏(nian)膜被(bei)破壞,不(bu)復(fu)存在(zai)(zai),發(fa)生(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)化(hua)(hua)學(xue)(xue)腐蝕。所以在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)(dian)拋(pao)光(guang)過(guo)程(cheng)中必(bi)須(xu)控制(zhi)陽(yang)(yang)極(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)密(mi)(mi)度在(zai)(zai)最佳(jia)值,也就(jiu)是在(zai)(zai)確(que)定的(de)(de)(de)工藝范圍(wei)內。


11. 陽極移(yi)動


 陽(yang)極(ji)(ji)移(yi)動使陽(yang)極(ji)(ji)溶解產物加快擴(kuo)散出(chu)去,起到攪拌作(zuo)用,有效地排除陽(yang)極(ji)(ji)表(biao)面(mian)滯留的氣泡,避免(mian)產生的氣流(liu)生成條紋,防止局部過(guo)(guo)熱造(zao)成表(biao)面(mian)過(guo)(guo)腐蝕。陽(yang)極(ji)(ji)移(yi)動有助于(yu)提(ti)高(gao)陽(yang)極(ji)(ji)電(dian)流(liu)密(mi)度,提(ti)高(gao)不(bu)銹鋼零件(jian)的電(dian)化(hua)學(xue)拋(pao)光表(biao)面(mian)質量(liang)。


12. 氯離子的危害


 在電(dian)(dian)化(hua)學(xue)拋光液(ye)中不允許有活(huo)性氯(lv)離(li)子(zi)(zi)存在,氯(lv)離(li)子(zi)(zi)能(neng)破壞電(dian)(dian)化(hua)學(xue)拋光中表(biao)面形成的保護(hu)性黏(nian)膜(mo),使不銹鋼表(biao)面形成過腐蝕性的麻(ma)點。氯(lv)離(li)子(zi)(zi)可在陽極(ji)高(gao)電(dian)(dian)流密度上氧化(hua)成氯(lv)氣逸出而(er)除去(qu)。氯(lv)離(li)子(zi)(zi)的來(lai)源可能(neng)是(shi)用鹽酸(suan)酸(suan)洗后未洗凈而(er)帶入(ru)槽液(ye),或原料中的不純物氯(lv)離(li)子(zi)(zi)引入(ru)。


13. 六價(jia)鉻和三價(jia)鉻的最佳配(pei)比(bi)


 在(zai)(zai)(zai)(zai)(zai)電(dian)(dian)(dian)化(hua)學拋(pao)光(guang)(guang)液(ye)(ye)(ye)(ye)(ye)中(zhong)(zhong)六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)有(you)氧(yang)化(hua)性,對不(bu)銹(xiu)鋼表(biao)(biao)面起鈍化(hua)保護作用(yong),三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)對維護電(dian)(dian)(dian)拋(pao)光(guang)(guang)有(you)作用(yong)。新配(pei)(pei)成(cheng)的(de)(de)(de)(de)電(dian)(dian)(dian)拋(pao)光(guang)(guang)液(ye)(ye)(ye)(ye)(ye)如(ru)果(guo)沒(mei)有(you)化(hua)學反(fan)應(ying)(ying)產生(sheng)三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge),還(huan)不(bu)能獲得良好的(de)(de)(de)(de)拋(pao)光(guang)(guang)表(biao)(biao)面。只有(you)當電(dian)(dian)(dian)解(jie)到溶液(ye)(ye)(ye)(ye)(ye)中(zhong)(zhong)有(you)一定量(liang)(liang)的(de)(de)(de)(de)三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)存在(zai)(zai)(zai)(zai)(zai)時,才(cai)能出現(xian)理(li)想的(de)(de)(de)(de)拋(pao)光(guang)(guang)表(biao)(biao)面。如(ru)果(guo)配(pei)(pei)方中(zhong)(zhong)加(jia)(jia)有(you)鉻(ge)(ge)(ge)(ge)(ge)酐(gan),即六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge),通過(guo)電(dian)(dian)(dian)解(jie)反(fan)應(ying)(ying),在(zai)(zai)(zai)(zai)(zai)陰(yin)極(ji)上產生(sheng)氫氣還(huan)原部分(fen)六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)成(cheng)為三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge);如(ru)果(guo)配(pei)(pei)方中(zhong)(zhong)沒(mei)有(you)鉻(ge)(ge)(ge)(ge)(ge)酐(gan),則三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)要(yao)靠陽(yang)極(ji)溶解(jie)不(bu)銹(xiu)鋼所含的(de)(de)(de)(de)鉻(ge)(ge)(ge)(ge)(ge)而得。這就是(shi)為什(shen)么(me)新配(pei)(pei)的(de)(de)(de)(de)電(dian)(dian)(dian)解(jie)拋(pao)光(guang)(guang)液(ye)(ye)(ye)(ye)(ye)要(yao)充分(fen)電(dian)(dian)(dian)解(jie)后(hou)才(cai)能進行正常的(de)(de)(de)(de)拋(pao)光(guang)(guang)工作。在(zai)(zai)(zai)(zai)(zai)含有(you)鉻(ge)(ge)(ge)(ge)(ge)酐(gan)的(de)(de)(de)(de)溶液(ye)(ye)(ye)(ye)(ye)中(zhong)(zhong),加(jia)(jia)入(ru)明膠或甘(gan)油,它們能和鉻(ge)(ge)(ge)(ge)(ge)酐(gan)起強烈(lie)的(de)(de)(de)(de)還(huan)原反(fan)應(ying)(ying),部分(fen)六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)轉變為三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)(Cr3+)。六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)是(shi)黃(huang)色(se)(se)的(de)(de)(de)(de),三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)是(shi)綠色(se)(se)的(de)(de)(de)(de)。它們在(zai)(zai)(zai)(zai)(zai)電(dian)(dian)(dian)解(jie)液(ye)(ye)(ye)(ye)(ye)中(zhong)(zhong)使溶液(ye)(ye)(ye)(ye)(ye)呈(cheng)黃(huang)綠色(se)(se)。這就是(shi)為什(shen)么(me)通電(dian)(dian)(dian)處(chu)理(li)后(hou)才(cai)可(ke)電(dian)(dian)(dian)解(jie)拋(pao)光(guang)(guang)。最(zui)佳(jia)的(de)(de)(de)(de)拋(pao)光(guang)(guang)質(zhi)量(liang)(liang)是(shi)在(zai)(zai)(zai)(zai)(zai)電(dian)(dian)(dian)解(jie)過(guo)程的(de)(de)(de)(de)中(zhong)(zhong)間(jian)階段。在(zai)(zai)(zai)(zai)(zai)生(sheng)產過(guo)程中(zhong)(zhong)電(dian)(dian)(dian)解(jie)拋(pao)光(guang)(guang)液(ye)(ye)(ye)(ye)(ye)要(yao)保持黃(huang)綠色(se)(se)。此時,根據化(hua)學分(fen)析數據,六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)與三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)的(de)(de)(de)(de)配(pei)(pei)比是(shi):含Cr6+30%,含Cr3+70%.為了維持該配(pei)(pei)比,可(ke)觀察電(dian)(dian)(dian)解(jie)液(ye)(ye)(ye)(ye)(ye)的(de)(de)(de)(de)顏(yan)色(se)(se),如(ru)果(guo)顏(yan)色(se)(se)呈(cheng)黃(huang)色(se)(se)為主,表(biao)(biao)明電(dian)(dian)(dian)解(jie)液(ye)(ye)(ye)(ye)(ye)含Cr6+偏高,可(ke)加(jia)(jia)入(ru)適(shi)量(liang)(liang)的(de)(de)(de)(de)明膠或甘(gan)油,使其部分(fen)六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)還(huan)原為三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge),或通過(guo)大陰(yin)極(ji)小(xiao)陽(yang)極(ji)電(dian)(dian)(dian)解(jie)產生(sheng)三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)。如(ru)果(guo)顏(yan)色(se)(se)呈(cheng)深綠色(se)(se),表(biao)(biao)明電(dian)(dian)(dian)解(jie)液(ye)(ye)(ye)(ye)(ye)含Cr3+高了,按(an)比例適(shi)量(liang)(liang)加(jia)(jia)入(ru)用(yong)水溶解(jie)好的(de)(de)(de)(de)鉻(ge)(ge)(ge)(ge)(ge)酐(gan)溶液(ye)(ye)(ye)(ye)(ye),或通過(guo)大陽(yang)極(ji)小(xiao)陰(yin)極(ji)電(dian)(dian)(dian)解(jie)拋(pao)光(guang)(guang)液(ye)(ye)(ye)(ye)(ye),使三(san)(san)(san)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)部分(fen)轉變成(cheng)六(liu)價(jia)(jia)(jia)(jia)鉻(ge)(ge)(ge)(ge)(ge)。同時可(ke)改善溶液(ye)(ye)(ye)(ye)(ye)的(de)(de)(de)(de)拋(pao)光(guang)(guang)質(zhi)量(liang)(liang)。


14. 金屬拋(pao)除(chu)量


 如果電(dian)解拋光時(shi)陽(yang)極(ji)電(dian)流密度為(wei)(wei)20A/d㎡,時(shi)間為(wei)(wei)4min時(shi),用工具金(jin)(jin)(jin)相顯微鏡觀(guan)測,不銹(xiu)鋼零件(jian)的(de)螺紋內徑的(de)金(jin)(jin)(jin)屬拋除(chu)(chu)量為(wei)(wei)每分鐘約0.001mm,螺紋外徑的(de)金(jin)(jin)(jin)屬拋除(chu)(chu)量為(wei)(wei)0.002mm,齒(chi)形基本無變化(hua),僅齒(chi)的(de)頂部略有拋鈍。陽(yang)極(ji)電(dian)流密度增(zeng)加,其金(jin)(jin)(jin)屬拋除(chu)(chu)量呈比例增(zeng)大。對于精密尺寸(cun)的(de)不銹(xiu)鋼零件(jian)的(de)尺寸(cun)應考慮電(dian)化(hua)學拋光后的(de)金(jin)(jin)(jin)屬拋除(chu)(chu)量(損耗)。


15. 電(dian)焊或熱處理后零件的電(dian)化學拋(pao)光


 凡電焊(han)(han)或熱處理后的(de)零(ling)件在電化學拋(pao)光時按兩次進行,第一次進槽(cao)拋(pao)光3~5min后取出,將(jiang)(jiang)已疏松了的(de)焊(han)(han)渣和熱處理氧化皮用(yong)(yong)金屬(shu)絲刷將(jiang)(jiang)它(ta)刷掉,或用(yong)(yong)小錘(chui)敲掉,再(zai)第二次進槽(cao)再(zai)拋(pao)光3~5min,可獲得較好的(de)效果。


16. 中和工序


 經(jing)過(guo)電化(hua)學(xue)(xue)(xue)拋光(guang)(guang)后(hou)的(de)(de)(de)零(ling)件(jian),如果(guo)不(bu)(bu)再(zai)進(jin)(jin)行(xing)后(hou)續加(jia)工,如電鍍、著色等其他(ta)工序,要(yao)進(jin)(jin)行(xing)鈍(dun)化(hua)和(he)中(zhong)(zhong)和(he)。中(zhong)(zhong)和(he)的(de)(de)(de)作用是充分地(di)消除在電化(hua)學(xue)(xue)(xue)拋光(guang)(guang)和(he)鈍(dun)化(hua)后(hou)表面(mian)所吸附的(de)(de)(de)酸性物(wu)質。中(zhong)(zhong)和(he)一般是在碳酸鈉20~30g/L的(de)(de)(de)溶液(ye)中(zhong)(zhong)進(jin)(jin)行(xing)的(de)(de)(de)。路(lu)云(yun)鶴認(ren)為,經(jing)過(guo)電化(hua)學(xue)(xue)(xue)拋光(guang)(guang)后(hou)的(de)(de)(de)零(ling)件(jian)表面(mian)有一層均勻的(de)(de)(de)鈍(dun)化(hua)膜,可不(bu)(bu)需(xu)要(yao)再(zai)進(jin)(jin)行(xing)鈍(dun)化(hua)處理(li)。不(bu)(bu)銹鋼零(ling)件(jian)電化(hua)學(xue)(xue)(xue)拋光(guang)(guang)后(hou),經(jing)過(guo)40℃的(de)(de)(de)溫(wen)水清(qing)(qing)洗(xi)(xi),再(zai)冷水清(qing)(qing)洗(xi)(xi),中(zhong)(zhong)和(he)并(bing)清(qing)(qing)洗(xi)(xi)后(hou)用壓(ya)縮(suo)空氣吹干,才(cai)可以有效(xiao)地(di)避免殘留酸液(ye)腐(fu)蝕拋光(guang)(guang)表面(mian)。