Effects of TIG surface treating on microstructural characteristics and mechanical properties of Al₂O₃-TiB₂ coating by APS

Authors: H. C. Cheng; Z. X. Li; Y. W. Shi

Source: Materials Science and Technology

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Abstract:

The pulsed DC tungsten inert gas (TIG) method was employed to post-spray treat an electroconductive Al₂O₃-TiB₂ coating by atmosphere plasma spraying (APS) Al₂O₃-30 wt-%TiB₂ powder. The microstructure and mechanical properties of the coatings before and after treatment were comparatively investigated by scanning electron microscopy, laser scanning confocal microscopy, X-ray diffraction, microhardness tester and block on ring wear tester. It was detected that the treated coating presented a two layer structure consisting of the remelted zone and the sintered zone, which was comprised of TiB₂ and single α-Al₂O₃; surface roughness of the treated coating exhibited a remarkable decrease while microhardness and wear resistance showed a significant increase. These experimental results could be ascribed to the effect of high heat input and discharge plasma during the pulsed DC TIG treating.

Keywords: Atmosphere plasma spray

Document Type:

DOI: http://dx.doi.org/10.1179/17432840test

Affiliations: College of Material Science and Engineering, Beijing University of

Appeared or available online: November 23, 2010