Thermochemical wear of single crystal diamond catalyzed by ferrous materials at elevated temperature

Abstract

Single crystal diamond has been recognized as the optimal tool material in ultra-precision machining. However, the excessive tool wear prevents it from cutting ferrous materials. This paper conducts a series of thermal analysis tests under the conditions of different gas atmospheres, heating temperatures, crystallographic planes and workpiece materials, in order to clarify the details of thermochemical wear of diamond catalyzed by iron at elevated temperature. Raman scattering analysis was performed to identify the transformation of diamond crystal structure. Energy dispersive X-ray analysis was used to detect the change in chemical composition of the work material. X-ray photoelectron spectroscopy was adopted to confirm the resultants of interfacial thermochemical reactions. The experimental results revealed that the diamond wear included the graphitization, diffusion and oxidation. Temperature was considered as the key factor affecting these wear mechanisms. The initial graphitization temperatures of diamond catalyzed by iron under different conditions were obtained, and the graphitized degree relied heavily on the crystallographic plane while being insensitive to the workpiece material. The diffusion wear rule was preliminarily achieved by the established prediction model of the carbon atoms diffusing into the iron lattice, and the types and resultants of interfacial chemical reactions were deduced.