To explore the mechanism of material removal mode and the wear behaviour of Si3N4 ceramic balls in lapping process,the lapping process experiment was carried out based on the theory of dynamic indentation fracture mechanics of ceramic materials,and the surface morphology was examined using SEM and 3D optical microscopy.The finite element model for the impact of single diamond grain was established,and the simulation was carried out.The experimental results indicate that the main material removal mode is brittle fracture and powder removal.A large number of shelllike defects and clusters of randomly distributed powdery material areas remains on the surface of ceramic spheres.Ceramic ball surface has some defects such as wears,scratches and pits during the grinding process.Under the impact of abrasive particles,the surface material will be crushed and removed by microcutting,and brittle fracture will be removed by extrusion.When the abrasive particles act on the surface of ceramic ball in a rolling manner,the ceramic ball surface is more prone to powder removal,and the material removal rate is higher.The simulation results show that the order of maximum equivalent stress generated by the impact mode of each abrasive particle is as follows:rolling grinding grain variable cutting depth,rolling grinding grain fixed cutting depth,grinding grain extrusion,sliding grinding grain fixed cutting depth,among which,rolling grinding grain variable cutting depth produces the deepest subsurface crack.