Plasma sprayed α-Al₂O₃ main phase coating using γ-Al₂O₃ powders

ABSTRACT

Although α-Al₂O₃ is commonly used as crude materials for preparing Al₂O₃ coating by plasma spraying, the obtained coatings are mainly made up of γ-Al₂O₃ crystalline phase with relatively poor mechanical performance. In this research, we employed an unconventional way, i.e. adopting low-cost γ-Al₂O₃ powders as crude material via the optimisation of plasma spraying process to prepare a novel aluminium oxide coating containing α-Al₂O₃ crystals with excellent mechanical properties as main phase, and the microstructure, microhardness and tribological properties of the coating were characterised and analysed. The results indicated that the aluminium oxide coating possesses favourable toughness, strength and wear resistance (e.g. HV602.4 and wear loss ∼2.5 μm), consequently having a great potential for exploration and application.

KEYWORDS:

• γ-Al₂O₃
• α-Al₂O₃
• plasma spraying
• alumina coating
• wear resistance

Disclosure statement

No potential conflict of interest was reported by the authors.