活塞环表面等离子电解沉积陶瓷涂层的试验研究

Experimental research on ceramic coating of plasmaelectrolytic deposition on the surface of piston rings

为提升活塞环性能,采用液相等离子体电解沉积陶瓷涂层的技术方案,进行了活塞环表面强化的试验研究。分析了工作电压、处理时间和基体表面粗糙度对涂层结合力的影响规律,表征了PED陶瓷涂层的形貌和相组成。在此基础上,对比分析研究了PED陶瓷活塞环的硬度、摩擦学性能、耐腐蚀性能。研究结果表明:PED陶瓷涂层表面呈蜂窝状形貌,涂层的相由γ-Al_(2)O_(3)相和α-Al_(2)O_(3)相构成,且以α-Al_(2)O_(3)相为主晶相;PED陶瓷涂层与基体的结合力随工作电压的提高及处理时间的延长,均呈先增大后减小的趋势,随基体表面粗糙度的增大而增加。经PED处理后,试样的表面硬度可达1 185HV,其摩擦系数和磨损率分别降低了6.4%、29.4%;极化电阻提升至1.75×10^(4)Ω·cm^(2),较未处理活塞环提高一个数量级以上。

In order to improve the performance of piston rings,this paper studies the surface strengthening of piston rings by using the technical scheme of ceramic coating of plasma electrolytic deposition(PED).The effects of working voltage,treatment time and substrate surface roughness on the adhesion of the coating are analyzed.The morphology and phase composition of the PED ceramic coating are characterized.On this basis,the hardness,tribological properties and corrosion resistance of PED ceramic piston rings are compared and analyzed.The results show that the surface of the PED ceramic coating is honeycomb-shaped.The phase of the coating is composed ofγ-Al_(2)O_(3) phase andα-Al_(2)O_(3) phase,with theα-Al_(2)O_(3) phase as the main crystal phase.The adhesion between the PED ceramic coating and the substrate increases first and then decreases with the increase of the working voltage and the treatment time,while it increases with the increase of the substrate surface roughness.After PED treatment,the surface hardness of the sample can reach 1185HV,and its friction coefficient and wear rate reduce by 6.4%and 29.4%respectively.The polarization resistance increases to 1.75×104Ω·cm 2,which is more than an order of magnitude higher than that of an untreated piston ring.