In-situ Formed -Al2O3 Nanocrystals Repaired and Toughened Al2O3 coating Prepared by Plasma Spraying

Wednesday, May 23, 2012: 9:00 AM
Room 339 AB (Hilton Americas Houston )
Dr. Kai Yang , Shanghai Institute of Ceramics, Shanghai, China
In-situ formed γ-Al2O3 nanocrystals repaired and toughened Al2O3 coating prepared by plasma spraying

During process of plasma spraying of alumina with the stable α phase in the as-received powder, metastable γ phase tends to form in the as-deposited coating. In this paper, plasma-sprayed Al2O3 coating was investigated using transmission electron microscopy. In situ formation of γ-Al2O3 nanocrystals was observed in the pre-existing cracks of the as-sprayed Al2O3 coating, which contributes to self-repairing and self-toughening of the Al2O3 coating. Except for the predominant intergranular fracture, the pre-formed γ-Al2O3 nanocrystals would effectively obstruct the crack development in the coating and then the coating fracture toughness is enhanced.).