PROPERTIES OF YTTRALUMINIZING COATING ON Ni-BASE SUPERALLOYS

The yttraluminizing coating on the Ni-base superalloys has been developed by dipping thespecimens in a specially made yttrium-containing slurry as an underlayer and over spraying aCr-Al slurry as a protective layer,then heating to 1060℃ and holding for 1 h under argonatmosphere.Analysis by EPMA showed that the yttrium was concentrated in the intermediatezone of the coating as metallic compound Ni-5Y.After exposure to air up to 1000℃,theoxidation test revealed that the anti-oxidation resistance of the yttraluminizing coating withpost-aluminizing is much superior to that with single aluminizing only.