Metal separator for fuel cell and its production method

Abstract

The present invention provides a metallic separator for fuel cells capable of suppressing dropping out of conductive inclusions due to gaps formed at the interface of a base material and the conductive inclusions due to press-forming, thereby decreasing the contact resistance and enhancing the power generation performance, and also provides a method for producing the same.

1 . A metallic separator for fuel cells, comprising conductive inclusions projecting from a surface of a base material, the surface being treated by a chemical substance forming process for promoting volume expansion of the base material, and the conductive inclusions satisfying the relation 0.16≦R/r≦0.8, where R is a diameter equivalent to the average circle size of the conductive inclusions, and r is diameter equivalent to the average circle size of crystal grains of the base material. 
     
     
         2 . The metallic separator for fuel cells of  claim 1 , wherein the chemical substance forming process is a passivation process. 
     
     
         3 . A producing method for metallic separator for fuel cell for press-forming a separator material plate having conductive inclusions projecting from a surface, wherein the surface of the separator material plate is treated by a chemical substance forming process for promoting volume expansion of a base material. 
     
     
         4 . The producing method for a metallic separator for fuel cells of  claim 3 , wherein the chemical substance forming process is done after the press-forming process. 
     
     
         5 . The producing method for a metallic separator for fuel cells of  claim 3 , wherein the chemical substance forming process is a passivation process. 
     
     
         6 . The producing method for a metallic separator for fuel cells of  claim 4 , wherein the chemical substance forming process is a passivation process.