Plasma spray method for the manufacturing of an ion conducting membrane and an ion conducting membrane

Abstract

A plasma spray method for the manufacture of an ion conducting membrane, in particular of a hydrogen ion conducting membrane or of an oxygen ion conducting membrane is suggested. In which method the membrane is deposited as a layer ( 11 ) on a substrate ( 10 ) in a process chamber, wherein a starting material (P) is sprayed onto a surface of the substrate ( 10 ) by means of a process gas (G) in the form of a process beam ( 2 ). The starting material is injected into a plasma at a low process pressure which is at most 10000 Pa and is partially or completely melted there. In accordance with the invention the substrate ( 10 ) has pores ( 30 ) which are connected amongst one another so that the substrate ( 10 ) is gas permeable and a portion of an overall pore area of an overall area of the coating surface ( 31, 131 ) amounts to at least 30%, in particular to at least 40%.

1 . A plasma spray method for the manufacture of an ion conducting membrane, in particular of a hydrogen ion conducting membrane or of an oxygen ion conducting membrane, wherein the membrane is deposited as a layer ( 11 ,  111 ) on a substrate ( 10 , 110 ) in a process chamber ( 12 ), wherein a starting material (P) is sprayed onto a coating surface ( 31 ,  131 ) of the substrate ( 10 ,  110 ) by means of a process gas (G) in the form of a process beam ( 2 ), wherein the starting material is injected into a plasma at a low process pressure which is at most 10000 Pa and is partially or completely melted there,
 characterized in that   the substrate ( 10 ,  110 ) has pores ( 30 ) which are connected amongst one another so that the substrate ( 10 ,  110 ) is gas permeable and a portion of an overall pore area of an overall area of the coating surface ( 31 ,  131 ) amounts to at least 30%, in particular to at least 40%.   
     
     
         2 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the pores ( 30 ) have a mean pore size of at least 1 micrometer.   
     
     
         3 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the substrate ( 10 ,  110 ) has a useful porosity of at least 20%, in particular of at least 30% with respect to an overall volume of the substrate ( 10 ,  110 ).   
     
     
         4 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   micro-passages ( 140 ) are introduced into the substrate ( 110 ) before or after the coating for the improvement of a gas flow possibility in the direction of the coating surface ( 131 ).   
     
     
         5 . A plasma spray method in accordance with  claim 4 ,
 characterized in that   the micropassages ( 140 ) are orientated in the direction of the coating surface ( 131 ) from a rear substrate side ( 132 ) lying opposite the coating surface ( 131 ) and end before the coating surface ( 131 ).   
     
     
         6 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the substrate ( 10 ,  110 ) is manufactured from an iron alloy which has a portion of chrome which is larger than 20 weight percent and in particular is larger than 25 weight percent.   
     
     
         7 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   process parameters are set so that a temperature of the substrate ( 10 ,  110 ) amounts to between 250 and 850° C. during the carrying out of the method.   
     
     
         8 . A plasma spray method in accordance with  claim 7 ,
 characterized in that   process parameters are set so that a temperature of the substrate ( 10 ,  110 ) is higher than a temperature boundary of in particular 800° C. only for a maximum period of time, in particular of 5 minutes, during the carrying out of the method.   
     
     
         9 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the layer ( 11 ,  111 ), which forms the membrane, is composed of a ceramic material which is an oxide of the perovskite type.   
     
     
         10 . A plasma spray method in accordance with  claim 9 ,
 characterized in that   the layer ( 11 ,  111 ) is composed of a perovskite which includes lanthanum (La), strontium (Sr), cobalt (Co), iron (Fe), chromium (Cr), titanium (Ta), barium (Ba), zirconium (Zr), cerium (Ce), yttrium (Y), ytterbium (Yb), europium (Eu) or aluminum (Al).   
     
     
         11 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the layer ( 11 ,  111 ) generated on the substrate ( 10 ,  110 ) has a thickness of less than 150 micrometers.   
     
     
         12 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   an overall flow rate of the process gas is smaller than 200 SLPM and in particular amounts to 100 to 160 SLPM.   
     
     
         13 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the process gas is a mixture of argon and helium.   
     
     
         14 . A plasma spray method in accordance with  claim 1 ,
 characterized in that   the process beam ( 2 ) is pivoted or rastered relative to the coating surface ( 31 ,  131 ) of the substrate.   
     
     
         15 . An ion conducting membrane, in particular a hydrogen ion conducting membrane or an oxygen ion conducting membrane on a substrate ( 10 ,  110 ) which is deposited as a layer ( 11 ,  111 ) on the substrate ( 10 ,  110 ) with a plasma spray method in a process chamber ( 12 ), wherein a starting material (P) is sprayed onto a coating surface of the substrate ( 10 ,  110 ) by means of a process gas (G) in the form of a process beam ( 2 ), wherein the starting material is injected into a plasma at a low process pressure which is at most 10000 Pa and is partially or completely melted there,
 characterized in that   the substrate ( 10 ,  110 ) has pores ( 30 ) which are connected amongst one another so that the substrate ( 10 ,  110 ) is gas permeable and a portion of an overall pore surface of an overall surface of the coating surface ( 31 ,  131 ) amounts to at least 40%.