Effect of abrasive grit size on surface damage of AlN ceramics in precision grinding

Aluminum nitride (AlN) ceramics are widely used in high-power electronic packaging and thermal management applications owing to their excellent thermal conductivity and electrical insulation properties. However, their high hardness and intrinsic brittleness make them susceptible to severe surface and subsurface damage during precision grinding, which can significantly degrade component reliability. In this study, the effects of abrasive grit size on the surface integrity of AlN ceramics were systematically investigated using diamond grinding wheels with grit sizes of 325#, 600#, 1500#, and 5000#. The results demonstrate that both surface roughness and subsurface damage depth decrease monotonically with increasing abrasive grit size. A clear transition in material removal mechanism is observed, from crack-dominated brittle fracture at coarse grit sizes to plastic deformation dominated by dislocation activity at ultra-fine grit sizes. These findings provide a comprehensive understanding of grinding-induced damage evolution in AlN ceramics and offer practical guidance for optimizing grinding processes to achieve low damage and high reliability.