Substrate stainless steel sheet for fuel cell separators and production method therefor

1. A production method for a substrate stainless steel sheet for fuel cell separators, comprising:

preparing a stainless steel sheet as a material; and

subjecting the stainless steel sheet to heat treatment of holding in an atmosphere containing 1 vol. % or more oxygen and in a temperature range of 350° C. or more to 500° C. or less for 1 second or more and 120 seconds or less to thereby set [chemical form other than metal (Cr+Fe)]/[metal chemical form (Cr+Fe)] at 12.0 or more and 200 or less, [chemical form other than metal (Cr+Fe)]/[metal chemical form (Cr+Fe)] being a ratio of a total of Cr and Fe existing in chemical form other than metal to a total of Cr and Fe existing in metal chemical form at a stainless steel sheet surface,

wherein [metal chemical form (Cr+Fe)] is a total atomic concentration of Cr and Fe existing in metal chemical form and [chemical form other than metal (Cr+Fe)] is a total atomic concentration of Cr and Fe existing in chemical form other than metal, which are measured by analyzing the stainless steel sheet surface after heat treatment by X-ray photoelectron spectroscopy, and

wherein the substrate stainless steel sheet is in a state before a conductive coating is formed on its surface.

2. The production method according to claim 1 , wherein the temperature range of the heat treatment is 350° C. or more to 450° C. or less.

3. The production method according to claim 1 , wherein the substrate stainless steel sheet does not have the conductive coating on its surface.

4. The production method according to claim 2 , wherein the substrate stainless steel sheet does not have the conductive coating on its surface.

5. The production method according to claim 1 , wherein a heat treatment time of the heat treatment is 1 second or more and 1 minute or less.

6. The production method according to claim 2 , wherein a heat treatment time of the heat treatment is 1 second or more and 1 minute or less.

7. The production method according to claim 3 , wherein a heat treatment time of the heat treatment is 1 second or more and 1 minute or less.

8. The production method according to claim 4 , wherein a heat treatment time of the heat treatment is 1 second or more and 1 minute or less.