CURRENT DEVELOPMENTS INTO THE DIRECTION OF EFFECTIVE PROCESSING OF PCD, SCD AND CVD DIAMONDS FOR THEIR APPLICATION IN THE DIAMOND-ELVANIC WORKING LAYER OF A PRECISION RULING TOOL

Abstract

The article focuses on modern publications devoted to the effective surface treatment of PCD, SCD and CVD diamonds, with regard to the conditions of their application in precision diamond cutting tools. In modern literature, directed effects on the surface of diamonds have been studied to improve their machinability and it has been shown that in addition to the three most well-known: thermal, laser, and chemical, studies have recently been added on such effects as plasma, UV radiation, the environment, and the effect of the existing substrate on the diamond layer. For PCD with cobalt removed, it was found that the cobalt pre-removal process can effectively inhibit diamond graphitization at high temperature. It was confirmed that the microstructure of the WC-Co substrate, even with small changes in WC grain size, significantly affects the morphology of the CVD diamond coating, crystal quality and bond strength. The transition metal converts the grains of polycrystalline diamond plates into amorphous carbon, which ensures their rapid removal. For processing polycrystalline diamond, Fe, Ti and Ni are added to resin-based diamond wheels, with Fe showing the best results. In a nitrogen environment, the friction coefficient between Fe and diamond is lower than in air. The friction coefficient between diamond and silicon nitride is low in air and much higher in a vacuum environment. In reciprocating sliding machining, it has been found that the diamond material is removed as graphite rather than chipped off as fragments, and a high wear rate is achieved under ultraviolet irradiation. Another option for the transition of diamond to graphite to achieve high quality diamond surfaces is a combined method using inductively coupled plasma etching and dynamic friction polishing.