| abstract |
The object includes a main body and at least one protective layer, and the protective layer is located on at least one surface of the main body. The at least one protective layer is a thin film having a thickness of less than about 20 micrometers, and comprises a film selected from the group consisting of Y 3 Al 5 O 12 , Y 4 Al 2 O 9 , Er 2 O 3 , Gd 2 O 3 , Er 3 Al 5 O 12 , Gd 3 A ceramic composed of Al 5 O 12 and a ceramic compound. The ceramic compound includes a solid solution of Y 4 Al 2 O 9 and Y 2 O 3 -ZrO 2 . |