從圖5.22中可以看出，不同表面粗糙度的試樣的極化曲線都具有活性溶解-鈍化轉變的特征，并且都具有三個自腐蝕電位。當電位低于Ecorr-1時，三條曲線的腐蝕電流密度相差很小。因此為了簡化討論可以認為具有不同表面粗糙的試樣的陰極反應（H+的還原反應）是相同的，不隨表面粗糙度的變化而變化。金屬的陽極溶解電流隨著表面粗糙度的增加而增加，這種現象可以用金屬的表面功函數（EWF)來解釋。EWF是指材料的自由電子脫離材料表面的最低能量。金屬的暴露面積越大材料失去電子被氧化的概率就越高，且EWF隨著材料的表面粗糙度的增加而降低，表面粗糙度大的試樣具有較低的EWF和較大的有效暴露面積，因此越容易失去電子，從而加速材料的腐蝕過程。
圖5.25的理論極化曲線可以用來解釋不同表面粗糙度的雙(shuang)相(xiang)不(bu)銹(xiu)鋼(gang)的腐蝕過程。圖5.25中A1、A2、A3分別代表理論陽極極化曲線，B代表理論陰極極化曲線，陰、陽極極化曲線的交點個數即代表了自腐蝕電位的個數。假設B和A1分別代表240號砂紙打磨后的試樣的理論陰、陽極極化曲線，因此測量的極化曲線就是二者的代數疊加，從圖5.25中可以看出A1和B有三個交點（1、2、3),即表示有三個自腐蝕電位。當表面粗糙度降低（800號和拋光試樣）時，陽極極化曲線變為A2和A3,從圖5.25中可以看到仍然出現了三個交點（1'、2'、3')和（1”、2"、3”），即有三個自腐蝕電位。不同表面粗糙度的試樣的自腐蝕電位有如下關系：Ecorr-1<Ecorr1'<E corr-1",E corr-2<E corr-2,<E corr-2",E corr-3<Ecor-3/<Ecorr-3”。如果陽極極化曲線轉變為A4和A5,自腐蝕電位轉變為兩個或者一個，但是這種情況在本實驗條件下沒有出現。
從圖5.22中可以看出，溶液的pH值可以顯著改變雙相不銹鋼在酸性NaCl溶液中的腐蝕行為，從而使自腐蝕電位的個數隨著H*濃度的降低而減少。在酸性NaCI溶液中，主要的陰極反應是H*的還原反應。可以用圖5.26中的理論極化曲線來解釋pH值改變對自腐蝕電位個數的影響。圖5.26中曲線A1、A2和A3分別代表雙相不銹鋼在不同pH值的溶液中的理論陽極極化曲線，B1、B2和B3代表陰極H+還原反應的理論極化曲線。如果腐蝕過程是由陰極曲線B1和陽極曲線A1耦合而成，那么在金屬的活性溶解區、溶解－鈍化過渡區和完全鈍化區內陰、陽極極化曲線就會有三個交點（1、2、3),也就會出現三個自腐蝕電位。這對應于圖5.22(a)中H2SO4濃度大于0.011mol/L的條件下的情況。降低溶液的pH值，就會影響陰、陽極反應的過程，從而改變極化曲線的位置。當陰、陽極極化曲線由B2和A2耦合而成，則只有兩個交點，也就是只有兩個自腐蝕電位存在。這對應于圖5.22(b)中H2SO4濃度介于0.0065~0.011mol/L時的條件下所得到的結果。進一步降低溶液的pH值，使硫酸濃度降為0.005mol/L以下，陰、陽極極化曲線由B3和A3耦合而成，則只有一個自腐蝕電位存在。若進一步降低溶液的pH值，自腐蝕電位的個數將不再發生改變，保持一個。
圖5.26 雙相不銹鋼在不同氧含量和H2SO4濃度的0.5mol/L NaCl溶液中的腐蝕過程（A1、A2、A3為理論陽極極化曲線；B1、B2、B3為理論陰極極化曲線）在有氧存在的條件下，溶液中的陰極反應除了H+的還原反應之外，還有氧的還原反應：
O2+4H++4e- ＝ 2H2O
因此，在有氧(yang)(yang)存在條件(jian)下(xia)的(de)(de)陰極反應(ying)的(de)(de)電(dian)(dian)(dian)流(liu)密度是(shi)氫(qing)還(huan)原反應(ying)和氧(yang)(yang)還(huan)原反應(ying)的(de)(de)電(dian)(dian)(dian)流(liu)密度之和。從(cong)圖5.24中可以看出(chu)，溶液(ye)中的(de)(de)氧(yang)(yang)不但(dan)能影(ying)(ying)響陰極反應(ying)過程(cheng)，還(huan)能影(ying)(ying)響陽極反應(ying)過程(cheng)，造成自腐蝕電(dian)(dian)(dian)位正(zheng)移(yi)，腐蝕電(dian)(dian)(dian)流(liu)密度增加(jia)。可能是(shi)由(you)于溶液(ye)中的(de)(de)氧(yang)(yang)含量增加(jia)，獲得自由(you)電(dian)(dian)(dian)子的(de)(de)概(gai)率增加(jia)；或(huo)者提高氧(yang)(yang)在金(jin)屬表面(mian)或(huo)者鈍化膜表面(mian)的(de)(de)還(huan)原速度。
溶液(ye)(ye)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)含量對(dui)雙(shuang)相(xiang)不銹鋼(gang)在(zai)(zai)酸(suan)性NaCl溶液(ye)(ye)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)(de)(de)(de)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)行(xing)為(wei)的(de)(de)(de)(de)(de)(de)影(ying)響可(ke)(ke)以(yi)用(yong)圖(tu)(tu)(tu)5.27來(lai)(lai)解(jie)釋(shi)。氧(yang)(yang)(yang)(yang)(yang)(yang)對(dui)雙(shuang)相(xiang)不銹鋼(gang)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)行(xing)為(wei)的(de)(de)(de)(de)(de)(de)影(ying)響與pH的(de)(de)(de)(de)(de)(de)影(ying)響效果基本一(yi)致(zhi)。圖(tu)(tu)(tu)5.27(a)可(ke)(ke)用(yong)來(lai)(lai)解(jie)釋(shi)圖(tu)(tu)(tu)5.23(a)的(de)(de)(de)(de)(de)(de)實驗現(xian)象(xiang)。當溶液(ye)(ye)中(zhong)(zhong)(zhong)(zhong)不含氧(yang)(yang)(yang)(yang)(yang)(yang)（氮氣(qi)飽(bao)(bao)(bao)和(he)(he)(he)）時(shi)，B1和(he)(he)(he)A1分(fen)(fen)別代表理論(lun)的(de)(de)(de)(de)(de)(de)陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)。從(cong)(cong)圖(tu)(tu)(tu)5.27中(zhong)(zhong)(zhong)(zhong)可(ke)(ke)以(yi)看出(chu)(chu)曲(qu)(qu)(qu)線(xian)(xian)有(you)(you)三(san)個(ge)(ge)(ge)交點(dian)(dian)，即存在(zai)(zai)三(san)個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei) ECOrr-1、Ecorr-2和(he)(he)(he)Ecorr-3相(xiang)對(dui)應(ying)的(de)(de)(de)(de)(de)(de)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)流(liu)密度(du)為(wei)icorr-1、icorr-2和(he)(he)(he)icorr-3.當有(you)(you)氧(yang)(yang)(yang)(yang)(yang)(yang)存在(zai)(zai)（空氣(qi)飽(bao)(bao)(bao)和(he)(he)(he)或氧(yang)(yang)(yang)(yang)(yang)(yang)飽(bao)(bao)(bao)和(he)(he)(he)）時(shi)，陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)分(fen)(fen)別變為(wei)B2和(he)(he)(he)A2,仍(reng)然有(you)(you)三(san)個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)Ecorr-1'、Ecorr-2'和(he)(he)(he)Ecorr-3',并(bing)且 Ecorr-1'>E corr-1、Ecorr-21>Ecorr-2、Ecorr-3'>Ecorr-3。圖(tu)(tu)(tu)5.23(b)中(zhong)(zhong)(zhong)(zhong)在(zai)(zai)通(tong)氧(yang)(yang)(yang)(yang)(yang)(yang)前(qian)后都只有(you)(you)兩個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)，這(zhe)一(yi)現(xian)象(xiang)可(ke)(ke)以(yi)用(yong)圖(tu)(tu)(tu)5.27(b)來(lai)(lai)解(jie)釋(shi)。當溶液(ye)(ye)中(zhong)(zhong)(zhong)(zhong)通(tong)入氧(yang)(yang)(yang)(yang)(yang)(yang)前(qian)，B1和(he)(he)(he)A1分(fen)(fen)別代表理論(lun)的(de)(de)(de)(de)(de)(de)陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)，從(cong)(cong)圖(tu)(tu)(tu)5.27中(zhong)(zhong)(zhong)(zhong)可(ke)(ke)以(yi)看出(chu)(chu)曲(qu)(qu)(qu)線(xian)(xian)有(you)(you)兩個(ge)(ge)(ge)交點(dian)(dian)，即存在(zai)(zai)兩個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)Ecorr-1和(he)(he)(he)Ecorr-3,相(xiang)對(dui)應(ying)的(de)(de)(de)(de)(de)(de)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)流(liu)密度(du)為(wei)icorr-1和(he)(he)(he)icorr-3。當有(you)(you)氧(yang)(yang)(yang)(yang)(yang)(yang)飽(bao)(bao)(bao)和(he)(he)(he)時(shi)，陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)分(fen)(fen)別變為(wei)B2和(he)(he)(he)A2,仍(reng)然有(you)(you)兩個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei) Ecorr-1'和(he)(he)(he)Ecorr-3'。通(tong)氧(yang)(yang)(yang)(yang)(yang)(yang)前(qian)后自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)的(de)(de)(de)(de)(de)(de)關(guan)系(xi)為(wei)Ecorr-1'>Ecorr-1,Ecorr-3'>Ecorr-3.當硫酸(suan)濃度(du)為(wei)0.005mol/L時(shi)，在(zai)(zai)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)只有(you)(you)一(yi)個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)存在(zai)(zai)，但溶液(ye)(ye)經(jing)過(guo)氧(yang)(yang)(yang)(yang)(yang)(yang)飽(bao)(bao)(bao)和(he)(he)(he)后，自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)個(ge)(ge)(ge)數由一(yi)個(ge)(ge)(ge)增(zeng)加為(wei)兩個(ge)(ge)(ge)，這(zhe)一(yi)現(xian)象(xiang)可(ke)(ke)以(yi)用(yong)圖(tu)(tu)(tu)5.27(c)來(lai)(lai)解(jie)釋(shi)。空氣(qi)飽(bao)(bao)(bao)和(he)(he)(he)溶液(ye)(ye)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)(de)(de)(de)理論(lun)陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)分(fen)(fen)別為(wei)B1和(he)(he)(he)A1,從(cong)(cong)圖(tu)(tu)(tu)5.27中(zhong)(zhong)(zhong)(zhong)可(ke)(ke)以(yi)看出(chu)(chu)只有(you)(you)一(yi)個(ge)(ge)(ge)交點(dian)(dian)，即只存在(zai)(zai)一(yi)個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)；當氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)飽(bao)(bao)(bao)和(he)(he)(he)時(shi)，由于氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)促進了陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)反應(ying)過(guo)程，使陰(yin)(yin)、陽(yang)(yang)極(ji)(ji)極(ji)(ji)化(hua)(hua)曲(qu)(qu)(qu)線(xian)(xian)到達(da)B2和(he)(he)(he)A2,此時(shi)曲(qu)(qu)(qu)線(xian)(xian)有(you)(you)兩個(ge)(ge)(ge)交點(dian)(dian)，即出(chu)(chu)現(xian)兩個(ge)(ge)(ge)自(zi)腐(fu)(fu)(fu)(fu)(fu)蝕(shi)(shi)(shi)電(dian)(dian)(dian)(dian)(dian)位(wei)。
