| abstract |
To provide a coil spring for a fuel cell or a cartridge for a fuel cell, in which metal ion dissolution is surely controlled even if it contacts acid liquid contained in a fuel cell. The coil spring used for a fuel cell or a cartridge for a fuel cell is made of an austenite stainless steel and has no nickel plated layer on its surface and a cation index I as expressed in a formula I=A+2B+3C shall be 60 or less in which A, B, C stand for a monovalent metal ion concentration (ppb) per one coil spring, a concentration (ppb) except monovalent or trivalent metal ion and a trivalent metal ion concentration (ppb), respectively, in a methanol solution in the case the stainless member is dipped in 25 ml methanol solution (containing 1% water+4,000 ppm formic acid) and preserved under conditions of 60 DEG C for one week. |