( 1. 沈陽(yáng)師范大學(xué) 實(shí)驗(yàn)中心， 沈陽(yáng) 110034；
2. 中國(guó)科學(xué)院金屬研究所 金屬腐蝕與防護(hù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，
沈陽(yáng) 110016)
摘 要: 采用電弧熔煉(CA)和機(jī)械合金化(MA)通過(guò)熱壓燒結(jié)工藝制備了晶粒尺寸差別較大的Cu-40Ni合金， 借助于PARM273A和M5210電化學(xué)綜合測(cè)量?jī)x， 利用動(dòng)電位掃描法和交流阻抗技術(shù)對(duì)比研究了上述合金在酸性介質(zhì)中的腐蝕電化學(xué)性能以及腐蝕機(jī)理。 結(jié)果表明: 隨著H+濃度的增加， CA Cu-40Ni合金的自腐蝕電位負(fù)移， 而MA Cu-40Ni合金則正移， 兩種合金的動(dòng)電位掃描極化曲線均未出現(xiàn)鈍化現(xiàn)象； 隨著H+濃度的增加， CA Cu-40Ni合金的極化電阻增大， 腐蝕電流減小， 合金的耐蝕性能增加， 而MA Cu-40Ni合金的極化電阻減小， 腐蝕電流增加， 合金的耐蝕性能降低。 兩種合金的交流阻抗譜均由雙容抗弧組成， 腐蝕過(guò)程受電化學(xué)反應(yīng)控制。 晶粒細(xì)化后， 合金中存在大量晶界， 參與腐蝕反應(yīng)的活性原子數(shù)增加， 促使MA Cu-40Ni合金的腐蝕速度高于CA Cu-40Ni合金。
關(guān)鍵字: 銅鎳合金; 電弧熔煉; 機(jī)械合金化; 納米晶; 腐蝕電化學(xué)
（1. Experimental Center, Shenyang Normal University, Shenyang 110034, China;
2. State Key Laboratory for Corrosion and Protection,
Institute of Metal Research, Chinese Academy of Sciences,
Shenyang 110016, China）
Abstract: The corrosion mechanism and corrosion-resistances of Cu-40Ni alloy prepared by conventional casting (CA), mechanical alloy (MA) and hot-pressing processes with the great difference in grain size in acidic media were investigated by PARM273A and M5210 electrochemical apparatus through the potentiodynamic polarization method and the electrochemical impedance spectroscopy (EIS) technique. The results show that the corrosion potential of CA Cu-40Ni alloy in acidic medium moves negtively, while MA Cu-40Ni alloy moves positively with the increase of the H+ concentration. There is no passive phenomenon in potentiodynamic polarization curve for the two alloys. With the increase of the H+ concentration, the polarization resistance increases, and the corrosion current decreases, so the corrosion resistance increases for CA Cu-40Ni alloy, while the polarization resistance decreases, and the corrosion current increases, so the corrosion resistance decreases for MA Cu-40Ni alloy. The electrochemical impedance spectroscopy (EIS) composed of double capacitive loops for the two alloys show that the corrosion process is controlled by electrochemical reaction. The corrosion rate of MA Cu-40Ni alloy becomes faster than that of CA Cu-40Ni alloy because the reduction in the grain size of MA Cu-40Ni alloy produces large concentrations of grain boundaries and increases the number of reactive atoms in alloy surface.
Key words: Cu-Ni alloy; conventional casting; mechanically alloying; nanocrystalline; corrosion electrochemistry
