Adhesion of coatings using adhesive bonding compositions

Abstract

A multi-layer article ( 1 ) disclosed herein contains a metallic substrate ( 2 ), a protective layer ( 6 ), and an adhesive bonding layer ( 14 ) including an oxygen-containing compound that bonds the adhesive bonding layer to the metallic substrate, the protective layer, or both. A method for forming the multi-layer article includes the steps of heating a protective bonding composition ( 20 ) to form a molten material ( 24 ) in contact with a metal-containing surface ( 2 ), allowing the molten material to cool and solidify into the adhesion bonding layer ( 14 ) affixed to the metal-containing surface, depositing a ceramic material ( 26 ) onto the adhesive bonding layer, and heating the ceramic material to form the protective layer ( 6 ) affixed to the adhesive bonding layer.

The invention claimed is: 
     
         1 . A multi-layer article, comprising:
 a metallic substrate;   a protective layer; and   an adhesive bonding layer comprising an oxygen-containing compound that bonds the adhesive bonding layer to the metallic substrate, the protective layer, or both.   
     
     
         2 . The article of  claim 1 , further comprising a plurality of anchors bonded to the adhesive bonding layer and to at least one of the metallic substrate and the protective layer,
 wherein:   the anchors comprise the oxygen-containing compound; and   a structure of the anchors is effective to adhere the metallic substrate, the protective layer, or both, to the adhesive bonding layer by forming inter-layer linkages such that one portion of the anchors is attached to the adhesive bonding layer and another portion of the anchors is attached to the metallic substrate or to the protective layer.   
     
     
         3 . The article of  claim 1 , comprising:
 a superalloy substrate;   a MCrAlY bond coat layer bonded to a surface of the superalloy substrate;   the adhesive bonding layer bonded to a surface of the MCrAlY bond coat layer; and   a ceramic thermal barrier layer bonded to a surface of the adhesive bonding layer.   
     
     
         4 . The article of  claim 1 , comprising:
 a superalloy substrate;   the adhesive bonding layer bonded to a surface of the superalloy substrate; and   a ceramic thermal barrier layer bonded to a surface of the adhesive bonding layer.   
     
     
         5 . The article of  claim 1 , wherein the oxygen-containing compound is at least one selected from the group consisting of a spinel compound, a perovskite compound, and a cuspidine compound. 
     
     
         6 . The article of  claim 1 , wherein the oxygen-containing compound is at least one selected from the group consisting of MgAlCrO 4 , FeCrO 4 , CaTiO 3 , and Ca 4 (Si 2 O 7 )(F,OH) 2 . 
     
     
         7 . The article of  claim 1 , wherein the adhesive bonding layer is formed from a protective bonding composition comprising at least one of:
 a mixture of MgO and Al 2 O 3  in respective proportions such that an adhesive bonding layer comprising Cr further comprises MgAlCrO 4 ;   a mixture of CaO and TiO 2  in respective proportions such that the adhesive bonding layer comprises CaTiO 3 ; and   a mixture of CaF 2  and SiO 2  in respective proportions such that the adhesive bonding layer comprises Ca 4 (Si 2 O 7 )(F,OH) 2 .   
     
     
         8 . The article of  claim 7 , satisfying at least one of the following conditions:
 (i) the protective bonding composition comprises at least one of
 greater than about 25 percent by weight of the MgO, and 
 greater than about 25 percent by weight of the Al 2 O 3 ; 
   (ii) the protective bonding composition comprises at least one of
 greater than about 5 percent by weight of the CaO, and 
 greater than about 5 percent by weight of the TiO 2 ; and 
   (iii) the protective bonding composition comprises at least one of
 greater than about 25 percent by weight of the CaF 2 , and 
 greater than about 20 percent by weight of the SiO 2 , 
   
       based on a total weight of the protective bonding composition. 
     
     
         9 . A multi-layer article, comprising:
 a metallic layer;   a protective layer; and   a plurality of anchors bonded to both the metallic layer and the protective layer,   wherein:   the anchors comprise an oxygen-containing inorganic compound; and   a structure of the anchors is effective to adhere the metallic layer to the protective layer by forming inter-layer linkages such that one portion of the anchors is attached to the metallic layer and another portion of the anchors is attached to the protective layer.   
     
     
         10 . The article of  claim 9 , further comprising an adhesive bonding layer disposed between the metallic layer and the protective layer and in direct contact with the anchors, wherein the anchors form the inter-layer linkages such that a first portion of the anchors is attached to the metallic layer, a second portion of the anchors is attached to the adhesive bonding layer, and a third portion of the anchors is attached to the protective layer. 
     
     
         11 . The article of  claim 9 , wherein the oxygen-containing inorganic compound is at least one selected from the group consisting of a spinel compound, a perovskite compound, and a cuspidine compound. 
     
     
         12 . The article of  claim 9 , wherein the oxygen-containing inorganic compound is at least one selected from the group consisting of MgAlCrO 4 , FeCrO 4 , CaTiO 3 , and Ca 4 (Si 2 O 7 )(F,OH) 2 . 
     
     
         13 . A method for forming a multi-layer article of  claim 1 , the method comprising:
 heating a protective bonding composition to form a molten material in contact with a metal-containing surface;   allowing the molten material to cool and solidify into the adhesive bonding layer affixed to the metal-containing surface;   depositing a ceramic material onto the adhesive bonding layer; and   heating the ceramic material to form the protective layer affixed to the adhesive bonding layer, to form the multi-layer article.   
     
     
         14 . The method of  claim 13 , wherein the protective bonding composition comprises at least two selected from the group consisting of MgO, Al 2 O 3 , CaO, TiO 2 , CaF 2  and SiO 2 . 
     
     
         15 . The method of  claim 13 , wherein the protective bonding composition comprises MgO and Al 2 O 3  in respective proportions such that the molten material in the presence of Cr contains MgAlCrO 4 . 
     
     
         16 . The method of  claim 15 , wherein a molar ratio of the MgO to the Al 2 O 3  ranges from about 1.5:1 to about 1:1.5 respectively. 
     
     
         17 . The method of  claim 15 , wherein the protective bonding composition comprises at least one of:
 greater than about 25 percent by weight of the MgO; and   greater than about 25 percent by weight of the Al 2 O 3 ,   
       based on a total weight of the protective bonding composition. 
     
     
         18 . The method of  claim 13 , wherein the protective bonding composition comprises CaO and TiO 2  in respective proportions such that the molten material contains CaTiO 3 . 
     
     
         19 . The method of  claim 18 , wherein a molar ratio of the CaO to the TiO 2  ranges from about 1.5:1 to about 1:1.5 respectively. 
     
     
         20 . The method of  claim 18 , wherein the protective bonding composition comprises at least one of:
 greater than about 5 percent by weight of the CaO; and   greater than about 5 percent by weight of the TiO 2 ,   
       based on a total weight of the protective bonding composition. 
     
     
         21 . The method of  claim 13 , wherein the protective bonding composition comprises CaF 2  and SiO 2  in respective proportions such that the molten material contains Ca 4 (Si 2 O 7 )(F,OH) 2 . 
     
     
         22 . The method of  claim 21 , wherein a molar ratio of the CaF 2  to the SiO 2  ranges from about 1.5:1 to about 2.5:1 respectively. 
     
     
         23 . The method of  claim 21 , wherein the protective bonding composition comprises at least one of:
 greater than about 25 percent by weight of the CaF 2 ; and   greater than about 20 percent by weight of the SiO 2 ,   
       based on a total weight of the protective bonding composition. 
     
     
         24 . The method of  claim 13 , wherein the metal-containing surface is a metallic substrate or is a bond coat layer affixed to a surface of the metallic substrate. 
     
     
         25 . The method of  claim 13 , further comprising removing a portion of the adhesive bonding layer before the depositing of the ceramic material, such that:
 anchors contained in the adhesive bonding layer are not removed and remain attached to the metal-containing surface; and   exposed portions of the anchors become attached to the protective layer during the heating of the ceramic material.