Method of manufacturing plasma-resistant coating film

Abstract

Disclosed herein is a method of manufacturing a plasma-resistant coating film. The method includes (1) forming a lower coating layer through a thermal spray process, on a base member, from a first rare earth metal compound powder including 90 to 99.9 wt % of first rare earth metal compound particles and 0.1 to 10 wt % of silica (SiO 2 ) particles, (2) processing the surface of the lower coating layer formed in step (1) to have an average surface roughness of 1 to 6 μm, and (3) forming an upper coating layer through a suspension plasma spray process, on the lower coating layer which is surface-treated in step (2), from second rare earth metal compound particles, to obtain a structurally dense and chemically stable plasma-resistant coating film with improved plasma resistance.

What is claimed is: 
     
         1 . A method of manufacturing a plasma-resistant coating film, the method comprising:
 (1) forming a lower coating layer on a base member to be coated from a first rare earth metal compound powder comprising 90 to 99.9 wt % of first rare earth metal compound particles and 0.1 to 10 wt % of silica (SiO 2 ) particles through a thermal spray process;   (2) processing a surface of the lower coating layer formed in step (1) to have an average surface roughness of 1 to 6 μm; and   (3) forming an upper coating layer on the lower coating layer that is surface-treated in step (2), through a suspension plasma spray process from a second rare earth metal compound powder.   
     
     
         2 . The method of  claim 1 , wherein the first rare earth metal compound powder comprises 95 to 99.9 wt % of rare earth metal compound particles and 0.1 to 5 wt % of silica (SiO 2 ) particles. 
     
     
         3 . The method of  claim 1 , wherein the first rare earth metal compound powder has a particle size of 10 to 60 μm, and the lower coating layer has a thickness of 50 to 500 μm. 
     
     
         4 . The method of  claim 1 , wherein the second rare earth metal compound has a particle size of 0.1 to 10 μm, and the upper coating layer has a thickness of 50 to 150 μm. 
     
     
         5 . The method of  claim 1 , wherein the lower coating layer has a porosity of less than 2 vol % and the upper coating layer has a porosity of less than 1 vol %. 
     
     
         6 . The method of  claim 1 , wherein each of the first rare earth metal compound and the second rare earth metal compound is selected from the group consisting of yttria (Y 2 O 3 ), yttrium fluoride (YF), and yttrium oxyfluoride (YOF). 
     
     
         7 . The method as set forth in  claim 1 , wherein the first rare earth metal compound is yttria (Y 2 O 3 ). 
     
     
         8 . The method of  claim 1 , wherein the thermal spray process in step (1) is atmospheric plasma spray. 
     
     
         9 . The method of  claim 1 , wherein the surface process in step (2) is performed by polishing using a diamond pad. 
     
     
         10 . A plasma-resistant member manufactured by the method of  claim 1 . 
     
     
         11 . A plasma-resistant coating film comprising:
 a lower coating layer formed on a base member to be coated and made from a first rare earth metal compound powder comprising 90 to 99.9 wt % of first rare earth metal compound particles and 0.1 to 10 wt % of silica (SiO 2 ) particles through a thermal spray process, the lower coating layer having an adhesive strength of 20 MPa or more with respect to the base member; and   an upper coating layer formed on the lower coating layer and made from a second rare earth metal compound particles through a suspension plasma spray process,   wherein the plasma-resistant coating film has a porosity of less than 1 vol %.   
     
     
         12 . The film of  claim 11 , wherein each of the first rare earth metal compound and the second rare earth metal compound is selected from the group consisting of yttria (Y 2 O 3 ), yttrium fluoride (YF), and yttrium oxyfluoride (YOF). 
     
     
         13 . The film of  claim 11 , wherein the first rare earth metal compound is yttria (Y 2 O 3 ). 
     
     
         14 . The film of  claim 11 , wherein the lower coating layer has a porosity of less than 2 vol % and the upper coating layer has a porosity of less than 1 vol %. 
     
     
         15 . The film of  claim 11 , wherein the lower coating layer has a thickness of 50 to 500 μm and the upper coating layer has a thickness of 50 to 150 μm.