Preparation of MCrAlY-Al2O3 composite coatings with enhanced oxidation resistance through a novel powder manufacturing process

Bai, Mingwen; Song, Bo; Reddy, Liam; Hussain, Tanvir

Abstract

MCrAlY-Al 2 O 3 composite coatings were prepared by using high velocity oxygen fuel (HVOF) thermal spraying with bespoke composite powder feedstock for high temperature applications. Powder processing via a suspension route was employed to achieve a fine dispersion of α-Al 2 O 3 sub-micron particles on the MCrAlY powder surfaces. This was, however, compromised by ~50% less flow-ability of the feedstock during spraying. Nevertheless, the novel powder manufacturing process introduced in this study has shown potential as an alternative route to prepare tailored composite powder feedstock for the production of metal matrix composites (MMC) materials. In addition, the newly developed MCrAlY-Al 2 O 3 composite coatings exhibited superior oxidation resistance, compared to conventional MCrAlY coatings, with the formation of nearly exclusively Al 2 O 3 scale after isothermal oxidation at 900 °C for 10 h. The addition of α-Al 2 O 3 particles in the MCrAlY coatings as a second phase was found to have promoted the formation of YAG oxides (Y x Al y O z) during spraying, and also accelerated the outwards diffusion of Al, which resulted in enhanced oxidation resistance.

Citation

Bai, M., Song, B., Reddy, L., & Hussain, T. (2019). Preparation of MCrAlY-Al2O3 composite coatings with enhanced oxidation resistance through a novel powder manufacturing process. Journal of Thermal Spray Technology, 28(3), 433–443. https://doi.org/10.1007/s11666-019-00830-y

• Journal Article Type: Article
• Acceptance Date: Jan 7, 2019
• Online Publication Date: Jan 23, 2019
• Publication Date: 2019-02
• Deposit Date: Jan 23, 2019
• Publicly Available Date: Jan 23, 2019
• Journal: International Thermal Spray Conference
• Print ISSN: 1059-9630
• Electronic ISSN: 1544-1016
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 28
• Issue: 3
• Pages: 433–443
• DOI: https://doi.org/10.1007/s11666-019-00830-y
• Keywords: MCrAlY; Alumina; Suspension; Bond Coat; HVOF; Oxidation
• Public URL: https://nottingham-repository.worktribe.com/output/1491527
• Publisher URL: https://link.springer.com/article/10.1007%2Fs11666-019-00830-y
• Additional Information: Received: 14 July 2018; Revised: 4 January 2019; First Online: 23 January 2019