Diamond and graphite coated with polyalloys by an immersion method

Abstract

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. © 2002 Elsevier Science B.V. All rights reserved.