Titanium material for solid polymer fuel cell separator use and method of production of same
The present invention provides titanium material for a separator for solid polymer fuel cell use comprised of titanium which has a surface layer part where conductive compound particles are affixed, which is excellent in contact resistance between the separator surface and carbon paper and in durability, and which is low in cost and superior in recyclability and a method of production of the same. This titanium material for separator use has on the surface of the titanium base material a film comprised of the titanium compound particles made of titanium carbide, titanium nitride, or titanium carbonitride and titanium oxide. The film has a thickness of 0.1 to 1 μm, the coverage rate is an area percentage of 20% or more, and the contents of carbon and nitrogen in the film total 5 to 40 at %. The titanium material for a separator is produced by annealing or shot blasting and pickling.
1. A titanium material for solid polymer fuel cell separator use, comprising a titanium base material on the surface of which is provided a film comprised of titanium oxide having a thickness of 100 nm to 1 μm and a surface coverage rate of said titanium base material by said film of 20% or more; said film further comprising conductive titanium compound particles of a spherical shape and having an average diameter of 50 nm to 1 μm, wherein said conductive titanium compound particles are comprised of one or both of carbon and nitrogen with titanium and the total content of carbon and nitrogen in the film is 5 to 40 at %, and wherein said particles are arranged to directly contact both the titanium base material and a carbon paper and/or are arranged such that two or more conductive titanium compound particles connect in the film such that the connecting particles directly contact both the titanium base material and the carbon paper.
2. The titanium material for solid polymer fuel cell separator use as set forth in claim 1 , wherein said titanium oxide is comprised of an oxide of one or more oxides selected from Ti 4 O 5 , Ti 3 O 5 , Ti 2 O 3 , TiO 2 , TiO, or amorphous state titanium oxide of an indeterminate ratio of composition.
3. The titanium material for solid polymer fuel cell separator use as set forth in claim 1 , wherein said titanium compound particles are comprised of one or more compounds selected from TiN, Ti 2 N, TiN 0.96 , TiC, Ti 2 C, TiC 0.98 , Ti 2 CN, TiC 0.7 N 0.3 , TiC 0.62 , TiC 0.59 , TiN 0.12 C 0.51 , TiC 0.3 N 0.7 , and TiC 0.2 N 0.8 .
4. The titanium material for solid polymer fuel cell separator use as set forth in claim 1 , wherein the total content of carbon and nitrogen in said film is 10 to 40 at %.