Characterization of Cr Coating Obtained on Micrometer-Scale Diamond Particles Prepared by Molten Salt Method

• Published in: Journal of superhard materials Vol. 44; no. 6; pp. 393 - 404
• Main Authors: Ge, Qingzhu, Yan, Meng, Jiang, Yang, Wang, Yonghong, Liu, Junwu
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2022; Springer Nature B.V
• Subjects: Chemistry; Chemistry and Materials Science; Chromium; Coatings; Diamonds; Electron microscopy; Metallizing; Molten salts; Parameter modification; Photoelectrons; Physical Chemistry; Process parameters; Properties; Salt baths; Spectrum analysis; Structure; Synthesis; Thermal conductivity; Thickness; Wettability; X ray photoelectron spectroscopy; diamond particles; interface bonding; molten salts method; Cr coatings; coating thickness
• ISSN: 1063-4576; 1934-9408
• DOI: 10.3103/S106345762206003X

The surface metallization can improve the wettability of the diamond particles and the metal matrix, which leads to large enhancement of the thermal conductivity of the composites. In this paper, chromium coatings obtained by molten salts method onto micrometer-scale diamond particles were used to modify the diamond’s surface topography. The influence of process parameters on the structure and morphology of the coating was investigated. The characteristics of coating were investigated by Scanning Electron Microscopy (SEM), Energy Disperse Spectroscopy (EDS), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Atomic Force Microscope (AFM). Part of the samples were ground and the thickness of the coating was measured by scanning electron microscope. The results show that, high deposition rate of chromium on diamond surface is obtained by molten salt. Integrated coating is formed when the content of Cr reaches 6% and the time of salt bath is beyond 40 min. Increasing the temperature of the molten salt method, up to 950°C, the probability of cracks on the coatings surface is reduced. Graphite can be detected when the heating temperature reaches 1050°C. When 6–10% Cr is added to salt mixture and heated to 950°C, integrated coating with excellent interface bonding can be achieved, and thickness of the coating film ranges from 312 to 826 nm.