Silicon oxycarbide-based environmental barrier coating

Abstract

An article includes a silicon oxycarbide-based layer that has Si, O, and C in a covalently bonded network. The silicon oxycarbide-based layer has first and second opposed surfaces. A calcium-magnesium alumino-silicate-based layer is interfaced with the first surface of the silicon oxycarbide-based layer.

What is claimed is: 
     
         1 . An article comprising:
 a silicon oxycarbide-based layer having Si, O, and C in a covalently bonded network, the silicon oxycarbide-based layer having first and second opposed surfaces; and   a calcium-magnesium alumino-silicate-based layer interfaced with the first surface of the silicon oxycarbide-based layer.   
     
     
         2 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer further includes SiO 2 . 
     
     
         3 . The article as recited in  claim 2 , wherein the silicon oxycarbide-based layer includes, by volume, 5-65% of the SiO 2  with a remainder of silicon oxycarbide. 
     
     
         4 . The article as recited in  claim 2 , wherein the SiO 2  is a continuous matrix phase with regions of the silicon oxycarbide dispersed there through. 
     
     
         5 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer further includes a dispersed phase of barium-magnesium alumino-silicate. 
     
     
         6 . The article as recited in  claim 5 , wherein the silicon oxycarbide-based layer includes, by volume, 1-30% of the dispersed phase of barium-magnesium alumino-silicate. 
     
     
         7 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer further includes a continuous matrix phase of SiO 2  and a dispersed phase of barium-magnesium alumino-silicate. 
     
     
         8 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer further includes a continuous matrix phase of barium-magnesium alumino-silicate and a dispersed phase of SiO 2 . 
     
     
         9 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer further includes a continuous matrix phase of SiO 2  or barium-magnesium alumino-silicate, the silicon oxycarbide-based layer including, by volume, 5-65% of the continuous matrix phase, and 1-30% of a dispersed phase of the other of the SiO 2  or barium-magnesium alumino-silicate, with a remainder of silicon oxycarbide. 
     
     
         10 . The article as recited in  claim 1 , wherein the calcium-magnesium alumino-silicate-based layer partially penetrates into the silicon oxycarbide-based layer such that at least a central core of the silicon oxycarbide-based layer is free of calcium-magnesium alumino-silicate-based material. 
     
     
         11 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer has a composition SiO x M z C y , where M is at least one metal, x<2, y>0 and z<1 and x and z are non-zero. 
     
     
         12 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer is thicker than the calcium-magnesium alumino-silicate-based layer. 
     
     
         13 . The article as recited in  claim 1 , wherein the calcium-magnesium alumino-silicate-based layer has an average thickness of 1 micrometer to 3 millimeters. 
     
     
         14 . The article as recited in  claim 1 , wherein the silicon oxycarbide-based layer includes discrete regions of silicon oxycarbide-based material, the discrete regions having an average maximum dimension of 1-75 micrometers. 
     
     
         15 . The article as recited in  claim 1 , the calcium-magnesium alumino-silicate-based layer sealing the silicon oxycarbide-based layer from oxygen diffusion and steam recession into the silicon oxycarbide-based layer. 
     
     
         16 . A composite comprising:
 a silicon oxycarbide-based material having Si, O, and C in a covalently bonded network, the silicon oxycarbide-based material having a surface; and   a calcium-magnesium alumino-silicate-based material interfaced with the surface of the silicon oxycarbide-based material.   
     
     
         17 . The composite as recited in  claim 16 , wherein the silicon oxycarbide-based material further includes a dispersed phase of barium-magnesium alumino-silicate. 
     
     
         18 . The composite as recited in  claim 17 , wherein the silicon oxycarbide-based material includes, by volume, 1-30% of the dispersed phase of barium-magnesium alumino-silicate. 
     
     
         19 . The composite as recited in  claim 16 , wherein the silicon oxycarbide-based material further includes a continuous matrix phase of SiO 2  or barium-magnesium alumino-silicate, and a dispersed phase of the other of barium-magnesium alumino-silicate or SiO 2 . 
     
     
         20 . The composite as recited in  claim 16 , wherein the silicon oxycarbide-based material has a composition SiO x M z C y , where M is at least one metal, x<2, y>0 and z<1 and x and z are non-zero.