Characterization and tribological evaluation of MW-PACVD diamond coatings deposited on pure titanium

Fu, Yong Qing, Yan, Bibo, Loh, Nee Lam, Sun, Chang Qing and Hing, Peter (2000) Characterization and tribological evaluation of MW-PACVD diamond coatings deposited on pure titanium. Materials Science and Engineering: A, 282 (1-2). pp. 38-48. ISSN 0921 5093

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Abstract

Titanium alloys are widely used in aerospace and biomedical conditions, however, they are notorious for the poor tribological properties. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, diamond coatings were deposited on pure titanium using microwave plasma assisted chemical vapour deposition (MW-PACVD). Characterisation of diamond coatings was performed using scanning electron microscopy (SEM), laser profilometry, Raman spectroscopy, grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM). Tribological properties of diamond coatings were evaluated using a ball-on-disk wear tester (sliding with Al2O3 balls) and a scratch tester (sliding with diamond pin). Results showed that the friction and wear properties of polycrystalline diamond coatings as well as the wear of the counterface were dependent significantly on the surface roughness, the morphology and crystalline structure of diamond coatings as well as the counterface materials. For (111)-textured diamond coatings with rough surface and sharp asperities sliding with Al2O3 balls, the coefficient of friction was much higher than that of (100)-textured coatings, and the wear of the counterface material was quite high. After polishing the diamond coating, the surface roughness, coefficient of friction and wear of counterface decreased significantly. If sliding with diamond pins, the coefficient of friction of diamond coating shows a quite low and stable value. To improve the tribological properties, a three-step deposition method was proposed to obtain a smooth and nano-crystalline diamond layer on bulk diamond coatings. The so-formed diamond coating showed the highest load bearing capacity, the lowest coefficient of friction and the lowest wear of the counterface.

Item Type:	Article
Uncontrolled Keywords:	Diamond, MW-PACVD; Titanium; Tribology; Wear; Coefficient of friction
Subjects:	F200 Materials Science
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Becky Skoyles
Date Deposited:	24 Mar 2015 15:00
Last Modified:	12 Oct 2019 19:05
URI:	http://nrl.northumbria.ac.uk/id/eprint/21758

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