Shi Xiaoliang, Xiu Shichao, Liu Xiao
School of Mechanical Engineering and Automation, Northeastern University, Shenyang, 110819, China.
Northeastern University, Shenyang, 110819, China.
Sci Rep. 2021 Dec 14;11(1):23926. doi: 10.1038/s41598-021-03493-4.
Workpiece will face corrosive problems during its application after the manufacturing process. As the common final process, grinding can generate special metamorphic layer on the surface of workpiece and change the initial corrosion resistance of workpiece. In order to study the corrosion resistance of workpiece after grinding process, the paper carries on combining experiment of grinding and electrochemical corrosion. The characteristic of corrosion resistance of grinding is revealed based on the association of grinding mechanism and electrochemical theory. The corrosion potential of workpiece after grinding is higher than matrix, which shows the grinding surface is difficult to begin to corrode. Electrochemical impedance spectroscopy (EIS) shows the grinding surface has large phase angle, impedance and capacitance characteristic because the metamorphic layer of grinding has good obstructive ability. They reveal that grinding improves the surface corrosion resistance of workpiece. Then the mechanism of the corrosion resistance of grinding is revealed. The special grain boundary formed in grinding with much C element, large clusters and complex shape prolongs the corrosion channel, which reduces the corrosive speed. While, the sensitive hardening structure generated in grinding hardening with much free energy is easy to form the corrosion cell, which will accelerate the corrosion.
工件在制造加工后的使用过程中会面临腐蚀问题。作为常见的最终加工工艺，磨削会在工件表面产生特殊的变质层，改变工件的初始耐腐蚀性。为了研究磨削加工后工件的耐腐蚀性，本文进行了磨削与电化学腐蚀的联合实验。基于磨削机理与电化学理论的关联，揭示了磨削耐腐蚀性的特性。磨削后工件的腐蚀电位高于基体，这表明磨削表面难以开始腐蚀。电化学阻抗谱（EIS）显示磨削表面具有较大的相角、阻抗和电容特性，因为磨削变质层具有良好的阻碍能力。它们表明磨削提高了工件的表面耐腐蚀性。进而揭示了磨削耐腐蚀性的机理。在磨削过程中形成的具有大量C元素、大团簇和复杂形状的特殊晶界延长了腐蚀通道，降低了腐蚀速度。而在磨削硬化过程中产生的具有大量自由能的敏感硬化组织容易形成腐蚀微电池，会加速腐蚀。
