EFFECT OF INCIDENCE ANGLE ON THE IMPACT-WEAR BEHAVIOR OF SILICON-NITRIDE

Experiments were conducted by repeatedly hammering a silicon nitride ( S3N4) ball on a polished different Si3N4 material at different inciden ce angles: 45 degrees, 60 degrees, 75 degrees, and 90 degrees, Materia l removal during impact was dominated by the delamination process, whi ch involved abrasion and fracturing of the parent material, compaction of pulverized debris into a film, nucleation of cracks along the film /substrate interface, and lateral propagation of the interfacial crack s. The dependency of repeated impact wear on the incidence angle invol ved a combination of the effects of normal and tangential stresses on surface deformation, The contrasting influences of these stresses resu lted in a minimization of impact wear of the polished Si3N4 material a t incidence angles in the range of 60 degrees-75 degrees.