Development of mechanochemical diamond stone containing BaSO4 abrasive

This paper describes a newly developed mechanochemical superabrasive stone containing reactive BaSO4 abrasive. A thermodynamic analysis suggested that BaSO4 reacts with Fe forming oxides. X-ray diffraction patterns revealed that scales that cover steels heated with BaSO4 abrasive consist of Fe3O4, α-Fe and BaS. On the basis of these results, vitrified diamond stones containing BaSO4 abrasive were manufactured and the effect of the BaSO4 abrasive on their performances was evaluated through the superfinishing of bearing steels. It was found that soft BaSO4 abrasive rubs the surface of hardened steel producing smooth surfaces with valleys. The stone reduces both the hardened layer depth and the compressive residual stress in the finished surface because of the formation of a thin white layer. The addition of BaSO4 abrasive improves the wear resistance of diamond stone because the dominant wear mechanism changes from carbon diffusion to oxidization of diamond.