目的 研究汽车发动机活塞顶面Ni基复合镀层中SiC颗粒的含量和粒径对活塞?镀层界面热应力的影响规律。方法 利用ABAQUS软件和Python语言建立顶面带有SiC颗粒增强Ni基复合电镀涂层活塞的二维有限元模型，结合热传递和热弹性相关理论及活塞的实际服役工况，确定活塞的换热边界条件及其顶面所受的载荷，采用顺序热力耦合的有限元分析方法，系统地研究热?机载荷共同作用下SiC颗粒含量和粒径对涂层?活塞界面应力的影响规律。结果 有限元仿真结果表明，当活塞顶面承受高温、高压时，SiC颗粒的含量是显著影响涂层?基体界面等效应力的因素之一，当SiC颗粒的体积分数为1%~15%时，涂层?活塞界面峰值等效应力随着颗粒含量的增加而增大，从437.08 MPa增大到472.98 MPa;SiC颗粒的粒径是影响涂层?基体界面耦合热应力的次要因素，当SiC颗粒的粒径为0.3~1 μm时，涂层?活塞界面峰值等效应力基本保持不变，约为437 MPa。结论 综合考虑活塞顶面复合电镀涂层的性能需求，以及镀层?活塞界面应力与结合性能的关系，结合实际复合电镀工艺，确定Ni?SiC复合镀层中SiC颗粒的体积分数以10%左右为宜，SiC颗粒的粒径以0.4~0.8 μm为宜。

The work aims to study the effect law of the content and size of SiC particles in Ni-based composite electroplating coating on the top surface of automobile engine piston on the thermal stress at the piston-electroplating coating interface. The two-dimensional finite element model of the piston with SiC particles reinforced Ni-based composite electroplating coating on the top surface was established by ABAQUS software and python language. Combined with the relevant theories of heat transfer and thermo-elasticity and the actual service conditions of the piston, the heat exchange boundary conditions and the load value on the top surface of the piston were determined. The effects of SiC particle content and size on the interfacial stress between coating and piston under the combined action of heat and airborne load were systematically studied by the sequential thermal mechanical coupling finite element analysis. According to the finite element simulation results, when the top surface of the piston was subject to high temperature and high pressure, the content of SiC particles was one of the factors that significantly affected the equivalent stress at the coating-matrix interface. The peak equivalent stress at the coating-piston interface increased with the increase of the particle content in the range of 1vol.%-15vol.%, rising from 437.08 MPa to 472.98 MPa. The size of SiC particle was a secondary factor affecting the coupling thermal stress at the coating-matrix interface. When the SiC particle size was in the range of 0.3-1 μm, the peak equivalent stress at the coating-piston interface remained unchanged, which was about 437 MPa. Considering the performance requirements of the composite electroplating coating on the top surface of the piston and the relationship between the stress at the coating-piston interface and the bonding property and combined with the actual electroplating process, it is determined that the volume fraction of SiC particles in Ni?SiC composite electroplating coating is about 10% and the diameter of SiC particles is about 0.4-0.8 μm.