Mechanical Properties and Uniformity of Nanocrystalline Diamond Coating Deposited Around a Sphere by MPCVD

Nanocrystalline diamond coatings were deposited by MPCVD on the spheres used for a ball bearing. The nanocrystalline coatings with a grain size of 50 nm were con?rmed by the surface morphology and composition analysis. The hardness of the coating is 20-40 GPa tested by nanoindentation, which is higher than that of tungsten carbide and silicon nitride substrates. The coating around the sphere observed from the Micro CT images is uniform with a thickness of 12 μm.