| 摘要 |
A coil spring for fuel cells, used for a fuel cell or a cartridge for the fuel cell, comprising an austenite type stainless steel without any nickel layer formed on the surface thereof, and having a cationic index I of not more than 60 as expressed by the following formula (1), I=A+2B+3C  (1) wherein A, B and C represent, respectively, a concentration (ppb) of monovalent metal ions, a concentration (ppb) of metal ions which are neither monovalent nor trivalent, and a concentration (ppb) of trivalent metal ions per the coil spring in a methanol solution of when the coil spring is dipped in the methanol solution (containing 1% of water+4000 ppm of formic acid) and preserved therein at 60° C. for one week. Even when brought into contact with the content solution exhibiting acidity of the fuel cell, the coil spring reliably suppresses the elution of metal ions thereof.
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