Abstract
The paper presents results of research into thermal barrier coatings characterized by higher oxidation resistance. Bondcoats were formed by overaluminizing of the MeCrAlY coating, deposited by low pressure plasma spraying (LPPS). The outer ceramic layer of yttrium oxide stabilized zirconia oxide was deposited by plasma spray physical vapour deposition (PS-PVD). For comparison purposes additionally formed were MeCrAlY bondcoats, which were not subsequently aluminized. The research showed that during CVD overaluminizing there was formed an additional layer built of the β-NiAl phase, which protects the base material from oxidation. Preserved below it increased chromium content ensures resistance to hot corrosion. The outer layer was characterized by columnar structure, similar to that obtained in the EB-PVD process. The isothermal oxidation tests showed that thickness of the TGO layer into overaluminized bondcoat significantly thicker in comparison with conventional LPPS-sprayed MeCrAlY bondcoats.
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