Ion implantation into race surfaces of aerospace ball bearings in a plasmaimmersion configuration

Plasma immersion ion implantation (PIII) is an effective technique to impro ve the surface properties of industrial components possessing an irregular shape, such as ball bearings used in the aerospace industry. The implant un iformity and efficiency along both the inner and outer races of a ball bear ing assembly is investigated experimentally and theoretically. We study the sample placement as well as different PIII processing conditions. The use of a three dimensional (3-D) model to investigate the influence of the samp le stage on the implantation efficiency and dose uniformity is described. B ased on the experimental results, under typical PIII conditions, the dose v ariation along the outward-facing groove of the inner ring of the ball bear ing assembly is 60%, whereas that along the inward-facing groove of the out er ring is 51%, By using a shorter pulsewidth and higher plasma density, th e nonuniformity is improved to about 35%, which is acceptable to the aerosp ace industry, The experimental observations are in agreement with simulatio n results, and the improvement can be attributed to the better conformabili ty of the plasma sheath to the race surface, Our results demonstrate the vi ability of PIII to enhance the surface properties of both the inner and out er rings of industrial ball bearings.