作　　者： (周文）; (兰伟）; (赵帅）; (曹献龙）; (邓洪达）;

机构地区： 重庆科技学院冶金与材料工程学院,重庆401331

出　　处： 《表面技术》 2017年第8期216-220,共5页

摘　　要： 目的通过研究42CrMo钻具用钢在常温下不同Cl^-浓度溶液中的腐蚀行为,为其腐蚀速率的预测奠定一定基础。方法采用浸泡实验、电化学测试技术研究42CrMo在不同浓度NaCl溶液中的平均腐蚀速率和电化学特性,并结合SEM扫描电镜对浸泡58 h后的挂片试样进行分析。结果浸泡实验分析表明,当Cl^-达到60 g/L时,42CrMo钢的腐蚀速率达到最大值,为0.124 g/(m^2·h);当Cl^-浓度继续增大时,腐蚀速率随Cl^-浓度的增加而逐渐减小。开路电位Eocp分析表明,随着Cl^-浓度的增加,Eocp总体呈现下降趋势,显示出较大的腐蚀倾向性。极化曲线分析表明,阴极极化曲线的斜率明显比阳极大,并且自腐蚀电流密度在60 g/L Cl^-溶液中达到最大值,为5.952 35μA/cm^2。腐蚀形貌研究表明,42CrMo浸泡58 h后,表面的腐蚀产物分布并不均匀,均发生了局部点蚀现象。结论随着Cl^-浓度的不断增大,42CrMo钢的平均腐蚀速率呈现先增大后减小的趋势,且在Cl^-为60 g/L时,平均腐蚀速率最大。42CrMo钢在静态常温下高Cl^-浓度溶液中以局部点蚀为主,其电化学腐蚀过程主要受阴极去氧极化的控制。 The work aims to lay a foundation for predicting corrosion rate of steel for 42CrMo drilling tool use by studying its corrosion behavior provided with different C1- concentration at normal temperature. Average corrosion rate and electro- chemical characteristics of 42CrMo in NaC1 solution of different concentrations （mass concentration, applicable to the full text） were studied by immersion experiment and electrochemical testing technology, and lacing film specimen was analyzed with scanning electron microscope after 58 h immersion. Immersion experiment analysis showed that corrosion rate of 42CrMosteel reached a maximum of 0.124 g/（m2 ~ h）when the CF concentration reached 60 g/L, the corrosion rate decreased gradually as the C1 concentration increased when the C1- concentration increased gradually （more than 60 g/L）. Open circuit potential Eocp analysis showed that Eocp tended to decline as a whole with the increase of C1- concentration, and showed clear tendency toward corrosion. Polarization curve analysis showed that slope of cathodic polarization curve was significantly higher than that of anode, and the corrosion current density reached the maximum 5.952 35 ~A/cm2, in 60 g/L NaC1 solution. Corrosion morphol- ogy study of 42CrMo showed that the surface corrosion products were unevenly distributed and subject to local pitting after 58 h immersion. Average corrosion rate of 42CrMo steel first increases and then decreases as C1- concentration increases conti- nuously, and it reaches the maximum when the CF concentration is 60 g/L. 42CrMo steel in static state at room temperature is mainly subject to local pitting in high content of CF solution, and the electrochemical corrosion process is mainly controlled by cathodic oxygen depolarization.

关 键 词： 腐蚀行为 点蚀 耐蚀性 电化学特性