Porous support substrate with an electrically conductive ceramic layer

Abstract

An electrically conductive ceramic layer is deposited on a porous body. The porous body is formed of sintered Fe-based alloy grains and has a density of 40 to 70% of its theoretical density. The electrically conductive deposition layer preferably has a perovskitic structure and it is formed by a pulsed sputtering process. The layer has a low diffusivity for the elements in the iron group and is especially suitable for use in solid oxide fuel cells (SOFC).

1 . An open-pore gas-permeable support substrate, comprising:
 a porous body having a density of 40 to 70% of a theoretical density and being formed of sintered grains of a Fe-based alloy; and   an electrically conductive ceramic PVD layer with a perovskitic structure and a thickness of 0.1 to 5 μm deposited on said porous body.   
     
     
         2 . The substrate according to  claim 1 , wherein said Fe-based alloy contains 15 to 35% by weight Cr. 
     
     
         3 . The substrate according to  claim 1 , wherein said Fe-based alloy contains 0.01 to 2% by weight of one or more elements selected from the group consisting of Ti, Zr, Hf, Mn, Y, Sc, and rare earths. 
     
     
         4 . The substrate according to  claim 1 , wherein said Fe-based alloy contains an amount of up to 10% by weight Mo. 
     
     
         5 . The substrate according to  claim 1 , wherein said Fe-based alloy contains an amount of up to 10% by weight Al. 
     
     
         6 . The substrate according to  claim 1 , wherein said Fe-based alloy contains an amount of up to 5% by weight of one or more metals selected from the group consisting of Ni, W, Nb, and Ta. 
     
     
         7 . The substrate according to  claim 1 , wherein said Fe-based alloy contains 0.1 to 1% by weight O. 
     
     
         8 . The substrate according to  claim 1 , formed as a component of a solid oxide fuel cell (SOFC). 
     
     
         9 . The substrate according to  claim 1 , wherein said layer has a structural formula ABO 3 , where A includes one or more elements selected from the group consisting of La, Ba, Sr and Ca; and B includes one or more elements selected from the group consisting of Cr, Mg, Al, Mn, Fe, Co, Ni, Cu and Zn. 
     
     
         10 . The substrate according to  claim 1 , wherein said layer has a density >99% of a theoretical density. 
     
     
         11 . The substrate according to  claim 1 , wherein an impurity content is less than 0.5% by weight. 
     
     
         12 . The substrate according to  claim 11 , wherein the impurity content is less than 0.1% by weight. 
     
     
         13 . The substrate according to  claim 1 , wherein said Fe-based alloy includes 15 to 35% by weight Cr, 0.01 to 2% by weight of one or more elements selected from the group consisting of Ti, Zr, Hf, Mn, Y, Sc, rare earths, an amount of up to 10% by weight Mo and/or Al, an amount of up to 5% by weight of one or more metals selected from the group consisting of Ni, W, Nb, Ta, 0.1 to 1% by weight O, and a remainder Fe and impurities. 
     
     
         14 . The substrate according to  claim 1 , wherein said electrically conductive layer is a porous layer and wherein said porous body and said electrically conductive layer together form the gas permeable substrate.