阴离子介质对WC-10Co合金电化学腐蚀行为的影响  

Effect of Anions on Electrochemical Corrosion Behavior and Corrosion Mechanism of WC-Co Cemented Carbide

作　　者：万庆磊 张立[1] 柯荣现 王喆[1] 徐涛[2] 张忠健[2] 刘向中[2] 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083 [2]硬质合金国家重点实验室,湖南株洲412000

出　　处：《中国钨业》2015年第1期61-65,共5页China Tungsten Industry

基　　金：硬质合金国家重点实验室开放基金(201403002);湖南省战略性新兴产业科技攻关类项目(2014GK1028)

摘　　要：研究了WC-10Co合金在浓度分别为0.05 mol/L和0.1 mol/L的Na Cl、Na NO3以及Na2SO4等3种阴离子介质中的电化学腐蚀行为。采用电化学阻抗谱(EIS)和动电位极化曲线2种方法研究合金的电化学腐蚀行为,通过传质电阻R和自腐蚀电流密度Icorr2个动力学参数对阴离子介质及其浓度对合金的腐蚀性进行比较。通过合金腐蚀表面扫描电镜观察,结合合金在3种介质中EIS对应的等效电路图对腐蚀机理进行分析。结果表明,Na NO3介质对合金的腐蚀性最弱,Na2SO4介质对合金的腐蚀性最强;3种介质对合金的腐蚀性随其浓度增加而增强;合金在Na2SO4介质中的腐蚀机理较在其他2种介质中相对复杂。The electrochemical corrosion behavior and corrosion mechanism of WC-10Co cemented carbide were investigated in the electrolytes of NaNO3, NaCl and Na2SO4, with concentrations of 0.05 mol/L and 0.1 mol/L, respectively. Potentiodynamic polarization curve and electrochemical impedance spectroscopy were used to survey the electrochemical behavior. Two kinetic parameters, i.e. charge transfer resistance and corrosion current density were used to describe the corrosion resistance. The corrosion mechanism was studied according to the SEM images of the corrosion surface and the equivalent circuit in the three electrolytes. The results show that in terms of the corrosivity, NANO3 is the weakest; while, Na2SO4 is the most aggressive. The corrosivity of the electrolytes increases with the increasing of their concentrations. Additionally, the equivalent circuit for electrochemical impedance spectroscopy and hence the corresponding corrosion mechanism of WC-10Co cemented carbide in Na2SO4 are more complicated than those in NANO3 and NaCl.

关 键 词：硬质合金 电化学腐蚀行为 腐蚀介质 等效电路 腐蚀机理 

分 类 号：TG172[金属学及工艺—金属表面处理] TG135.5[金属学及工艺—金属学]