Tribochemical polishing CVD diamond film with FeNiCr alloy polishing plate prepared by MA-HPS technique

• Published in: Diamond and related materials 2012, Vol.21, p.50-57
• Main Authors: Yuan, Zewei, Jin, Zhuji, Kang, Renke, Wen, Quan
• Format: Article
• Language: English
• Subjects: Alloy cast iron; Alloy plating; Alloy steels; Austenitic stainless steels; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; CVD diamond film; Exact sciences and technology; Fullerenes and related materials; diamonds, graphite; Hot-press sintering; Intermetallic compounds; Material removal mechanism; Materials science; Mechanical alloying; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; Oxidation resistance; Physical properties of thin films, nonelectronic; Physics; Plates (structural members); Polishing; Polishing plate; Scanning electron microscopy; Specific materials; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); TCP (protocol); Thin film structure and morphology; Tribochemical polishing
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2011.10.015

A novel polishing plate is most important for tribochemical polishing (TCP) diamond. This paper investigated the mechanisms of TCP and pointed out the requirements for the polishing plate. Unpaired d electrons, vertical aligned principle, high hardness and oxidation resistance at elevated temperature were general requirements for polishing plate. Based on these requirements, FeNiCr alloy polishing plate was prepared by the combination technique of mechanical alloying and hot-press sintering. Optical microscope, scanning electron microscope, Talysurf surface profiler, X-ray diffraction, electron probe microanalysis and Raman spectroscope were employed to characterize the prepared polishing plate and identify the removal mechanism. It was found that FeNiCr alloy polishing plate had higher hardness and oxidation resistance than stainless steel 304 and cast iron. FeNiCr alloy polishing plate obtained a material removal rate of 3.7 μm/min, which was higher than that of stainless steel 304 plate, cast iron plate and TiAl alloy plate. The mechanism for TCP can be described as converting diamond into graphite through friction heating and the interaction of the diamond with a catalytic metal disk; the catalytic metal acted on the diamond surface by means of their unpaired d electrons. If the metal structure of polishing plate was suitable to vertically bond with several carbon atoms on diamond surface, diamond would tend to convert into graphite more easily. Finally the non-diamond carbon was removed by mechanical friction, oxidation and diffusion into metal disk. ► A model illustrated the conversion of diamond into graphite under metal catalysis. ► Four requirements were proposed for tribochemical polishing plate. ► FeNiCr alloy polishing plate was prepared by MA-HPS technique. ► The properties and performances of FeNiCr alloy polishing plate were characterized.