Carbon separator for solid polymer fuel cell, solid polymer fuel cell, and solid polymer fuel cell stack
View Patent ↗A carbon separator for a solid polymer fuel cell is provided that includes a core material made of steel, and a carbon layer. The chemical composition of the steel is, by mass %, C: more than 0.02% to 0.12% or less, Si: 0.05 to 1.5%, Al: 0.001 to 1.0%, Mn: 0.01 to 1.0%, P: 0.045% or less, S: 0.01% or less, N: 0.06% or less, V: 0.5% or less, Cr: more than 13.0% to less than 25.0%, Mo: 0 to 2.5%, Ni: 0 to 0.8%, Cu: 0 to 0.8%, REM: 0 to 0.1%, B: 0 to 1.0%, Sn: 0 to 2.5%, In: 0 to 0.1%, and the balance: Fe and impurities. The steel has therein precipitates including M 23 C 6 type Cr carbides that are finely precipitated and dispersed. A part of the precipitates protrude from the steel surface.
1. A carbon separator for a solid polymer fuel cell, the carbon separator comprising a core material made of steel and a carbon layer, the steel having a chemical composition consisting of, by mass %:
C: more than 0.02% to not more than 0.12%,
Si: 0.05 to 1.5%,
Al: 0.001 to 1.0%,
Mn: 0.01 to 1.0%,
P: 0.045% or less,
S: 0.01% or less,
N: 0.06% or less,
V: 0.5% or less,
Cr: more than 13.0% to less than 25.0%,
Mo: 0 to 2.5%,
Ni: 0 to 0.8%,
Cu: 0 to 0.8%,
REM: 0 to 0.1%,
B: 0 to 1.0%,
Sn: 0 to 2.5%, and
In: 0.001 to 0.1%, and
the balance: Fe and impurities,
the steel having therein precipitates including M23C6 type Cr carbides that are finely precipitated and dispersed, where M represents Cr, or Cr and Fe,
wherein a part of the precipitates protrude from the steel surface.
2. The carbon separator according to claim 1 , wherein the chemical composition contains, by mass %:
B: more than 0.0003% to not more than 1.0%.
3. The carbon separator according to claim 2 , wherein:
the precipitates further include M2B type borides, wherein M represents Cr, or Cr and Fe.
4. The carbon separator according to claim 2 , wherein:
the precipitates further include composite precipitates in which M23C6 type Cr carbides are precipitated on surfaces of M2B type borides as precipitation nuclei, wherein M represents Cr, or Cr and Fe.
5. A solid polymer fuel cell comprising the carbon separator according to claim 1 .
6. A solid polymer fuel cell stack comprising the solid polymer fuel cell according to claim 5 .
7. A solid polymer fuel cell comprising the carbon separator according to claim 2 .
8. A solid polymer fuel cell comprising the carbon separator according to claim 3 .
9. A solid polymer fuel cell comprising the carbon separator according to claim 4 .
10. A solid polymer fuel cell stack comprising the solid polymer fuel cell according to claim 7 .
11. A solid polymer fuel cell stack comprising the solid polymer fuel cell according to claim 8 .
12. A solid polymer fuel cell stack comprising the solid polymer fuel cell according to claim 9 .