Complex, the current collecting member, a gas tank and a fuel cell system

A complex capable of effectively suppressing the Cr diffusion, the current collecting member, provides a gas tank and a fuel cell system. A composite of the present invention comprises a substrate 201 containing Cr, provided on at least a part of the surface of the substrate 201, among the constituent elements excluding oxygen, Zn and Al one th and includes many second, since the first complex oxide layer 203 having a spinel type crystal structure is provided, it is possible to suppress the diffusion of Cr from the base material containing an Cr, long-term reliability improved can be a complex, this makes it possible to improve the long-term reliability of the current collector 20 and the gas tank 34 is formed, the fuel cell device having excellent long-term reliability in the use of these 30 it is possible to provide a. .The