Diamond and graphite coated with polyalloys by an immersion method

A method of coating diamond and graphite with polyalloys, such as Ti–Co–Cu, Cr–Ni–Cu, W–Cu–Co, etc., is presented in this paper. By adding a small amount of Ti powder, CoCl2 and CuCl into NaCl–KCl molten salt system, and immersing diamond or graphite into it, the reactions which listed thereafter: Ti+CoCl2→TiCl2+Co, Ti+CuCl→TiCl2+Cu, C+TiCl2→TiCl4+TiC, etc., occurred, and finally a Ti–Co–Cu coating was deposited on the diamond or graphite surface. Other polyalloy coatings, such as Cr–Ni–Cu, Cr–Co–Cu, and W–Cu–Co, etc., were also deposited in almost the same way. The coated materials were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with a wavelength dispersive spectrometer (WDS) line profile analysis. XRD analysis showed that the carbides of Ti, Cr, or W were formed during the coating process. It was also found that no vacuum or protective atmosphere was needed during the process.