Stainless steel having excellent surface electrical conductivity for fuel cell separator and manufacturing method therefor

Abstract

A stainless steel a fuel cell separator including a surface oxide layer having a bandgap energy of 2 eV or less. A value of the surface oxide atomic ratio ((sum of atomic concentrations of metal elements in metal oxide (MO)/(sum of atomic concentrations of metal elements in total oxides and hydroxides))) is 0.44 or less, as measured on the surface of a stainless steel containing 15 wt % or more of Cr by X-ray angle-resolved photoemission spectroscopy using an Al-Kα X-ray source under the condition where a take-off angle of photoelectrons is from 12° to 85°. The metal oxide (MO) includes a mixed oxide: M represents an alloying element other than Cr and Fe or a combination thereof in the matrix; and O represents oxygen; and the total oxides and hydroxides include a Cr oxide, a Cr hydroxide, an Fe oxide, an Fe hydroxide, and the metal oxide (MO).

Dependencies are inferred from the claim text.