Effects of ion implantation on scratching properties of diamond like carbon and boron carbide films

Nanoindentation hardness and microscratching characteristics of a diamond l ike carbon (DLC) and boron carbide (B-C) films and nitrogen ion implanted t hose films were evaluated by atomic force microscope (AFM). Adhesion and st rength of film were evaluated by an oscillatory scratching test with acoust ic emission (AE). 1. Nanoindentation hardness and elastic modulus of B-C film is higher than those of DLC films. Nanoindentation hardness and elastic modulus of both th ose films increased by ion implantation. 2. Microwear of B-C film was smaller than that of DLC film, similar to nano indentation hardness evaluated by AFM. Microwear resistance in microscratch ing test of DLC film was remarkably improved by N+-implantation. However, m icrowear of B-C film decreases contrarily by N+-implantation in spite of it s hardness increase, 3. From the evaluation of oscillatory scratching test, a critical load of D LC film that AE counts increases rapidly and film fracture occurred, remark ably increased by N+-implantation, However, critical load of B-C remarkably decreases by N+-implantation. These results corresponds to microwear prope rties in microscratching test.