Properties and applications of Ti-coated diamond grits

Diamond grits were coated with metal Ti by the vacuum slow vapor deposition method. The surface and interface characteristics of the Ti coating were studied using SEM and grazing incidence X-ray diffraction (GIXD). The strength of the Ti-coated diamond grits was measured by the single grit method and the thermal stability was investigated by differential thermal analysis. A diamond blade was produced with Ti-coated diamond grits and an Fe-based metal bond, and a sawing experiment was carried out. The configuration of the coated diamond grits on the working face was observed by use of a stereomicroscope. The results show that diamond grit strength improves after coating, the maximum increment reaching about 20%. The coating also can protect the diamond from oxidization, the oxidation temperature of the coated diamond grits reaching as high as 1024 °C. In comparison with un-coated diamond grits, the pull-out ratio of the coated diamond grits in the blade decreases dramatically from 60 to 20% and the protrusion height increases greatly also. Owing to the protection of the Ti coating on the diamond during sintering, the strength of the coated diamond eroded from the metal matrix is 24–50% higher than that of un-coated diamond in sintered tools. The blade life increases by 36%. Reducing the diamond grits concentration or using fine diamond grits can reduce the manufacturing cost of diamond tools.