Effect of Thermal Aging on Properties and Microstructure of AlSi-hBN Coating

摘要

A commercial abradable coating AlSi-hBN was fabricated by atmospheric plasma spraying and was thermal aged at 450°C in the atmospheric environment for 1000h. Thermal aging effect on coating abradablity, hardness, bond strength and microstructure were evaluated. It was found that coating abradability increased obviously after 2h thermal aging and slightly decreased for extended thermal aging time. A sharp decrease in both coating hardness and bond strength were found after 2h thermal aging and a slow increase occurred with the extended aging time. Relationships between coating properties and microstructure were studied. Decomposition of organic binder and sintering of AlSi matrix metal generated by thermal aging were found to be reasons for coating properties changes.