Method and system for promoting adhesion of arc-spray coatings

Abstract

Methods to promote adhesion of coatings on surfaces, such as promoting adhesion of arc-spray coatings or thermal-spray coatings onto surfaces such as metallic or ceramic surfaces. The method applies a non-thermal plasma stream at atmospheric pressure to an article surface, creating an energized surface region that promotes adhesion of an arc-spray coating. In one aspect, the arc-spray coating is applied onto a metallic or ceramic surface.

What is claimed is: 
     
         1 . A method to adhere an arc-spray coating to a surface of an article, the method comprising:
 generating a non-thermal plasma stream, the non-thermal plasma stream at atmospheric pressure;   positioning the surface of the article to receive the non-thermal plasma stream;   treating the surface of the article with the non-thermal plasma stream to create an energized surface region;   generating an arc-spray coating stream;   directing the arc-spray coating stream at the energized surface region; wherein:   the arc-spray coating stream forms an arc-spray coating surface associated with the energized surface region of the article.   
     
     
         2 . The method of  claim 1 , wherein the energized surface region comprises etched organic residues. 
     
     
         3 . The method of  claim 1 , wherein the non-thermal plasma stream comprises monatomic oxygen species. 
     
     
         4 . The method of  claim 1 , wherein the article is metallic and the surface is a metallic surface. 
     
     
         5 . The method of  claim 4 , wherein the energized surface region is a metal oxide region. 
     
     
         6 . The method of  claim 5 , wherein the metal oxide region comprises an outer oxide surface. 
     
     
         7 . The method of  claim 6 , wherein the arc-spray coating stream is directed at the outer oxide region. 
     
     
         8 . The method of  claim 1 , wherein the article is metallic, the surface comprises a metallic surface, and the arc-spray stream comprises a metal. 
     
     
         9 . The method of  claim 8 , further comprising the step of forming chemical bonding sites on the energized surface region, the chemical bonding sites promoting chemical bonding with the energized surface region. 
     
     
         10 . The method of  claim 1 , wherein the article is metallic and the surface is a metallic surface. 
     
     
         11 . The method of  claim 1 , further comprising the step of applying an auxiliary gas onto the surface of the article. 
     
     
         12 . The method of  claim 1 , wherein the non-thermal plasma stream comprises monatomic nitrogen. 
     
     
         13 . The method of  claim 1 , wherein the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma. 
     
     
         14 . The method of  claim 1 , wherein the surface is a metallic surface, and the non-thermal plasma stream comprises an energetic species chemically reactive with the metallic surface. 
     
     
         15 . The method of  claim 1 , further comprising the application of a gas curtain associated with the non-thermal plasma stream. 
     
     
         16 . The method of  claim 1 , wherein the arc-spray stream comprises a sheath of air plasma. 
     
     
         17 . The method of  claim 1 , wherein the energized surface region comprises etched inorganic residues. 
     
     
         18 . The method of  claim 1 , wherein the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a metal. 
     
     
         19 . The method of  claim 1 , wherein the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a cermet. 
     
     
         20 . The method of  claim 1 , wherein the article is ceramic, the surface comprises a ceramic surface, and the arc-spray stream comprises a ceramic. 
     
     
         21 . The method of  claim 1 , wherein the non-thermal plasma stream comprises monatomic chemical species. 
     
     
         22 . The method of  claim 1 , wherein the non-thermal plasma stream comprises a tailored gas that forms a tailored chemical species on the surface. 
     
     
         23 . The method of  claim 22 , wherein the tailored gas is ammonia and the tailored chemical species comprise amine groups. 
     
     
         24 . The method of  claim 22 , wherein the tailored gas is water and the tailored chemical species comprise hydroxyl groups. 
     
     
         25 . A method to bond an arc-spray coating to a metal surface of an article, the method comprising:
 generating a non-thermal plasma stream, the non-thermal plasma stream at atmospheric pressure and comprising monatomic oxygen;   positioning the metal surface of the article to receive the non-thermal plasma stream;   treating the metal surface of the article with the non-thermal plasma stream to create a metal oxide region, the metal oxide region comprising an outer oxide surface and etched organic residues;   generating a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma; and   directing the metallic arc-spray coating stream at the metal oxide region; wherein:   the molten metal bonds with the metal oxide region to bond the arc-spray coating to the metal surface of the article.   
     
     
         26 . A system to adhere an arc-spray coating to a surface of an article, the system comprising:
 a plasma generating device configured to generate a non-thermal plasma stream at atmospheric pressure; and   an arc-spray generating device configured to generate an arc-spray coating stream; wherein:   the non-thermal plasma stream is directed at the surface of the article to create an energized surface region;   the arc-spray coating stream is directed at the energized surface region; and   the arc-spray coating is adhered to the surface of the article.   
     
     
         27 . The system of  claim 26 , wherein the non-thermal plasma stream comprises monatomic oxygen, the article is metallic, the surface is a metallic surface, and the arc-spray stream comprises a metal. 
     
     
         28 . The system of  claim 27 , wherein the non-thermal plasma generating device is configured to direct an auxiliary gas onto the metallic surface, and the arc-spray coating stream is a metallic arc-spray coating stream comprising a stream of projected molten metal surrounded by a sheath of air plasma.