Transition metal nitride, separator for fuel cells, fuel cell stack, fuel cell vehicle, method of manufacturing transition metal nitride, and method of manufacturing separator for fuel cells

摘要

A transition metal nitride obtained by nitriding a base material including an austenitic stainless steel having a Cr concentration of 25% or more includes a first layer (first nitrided layer) formed continuously on a base layer formed by the base material, having a stacked crystal structure of a nano-level including a nitride having a cubic crystal structure of M4N type, and a nitride having a hexagonal crystal structure of M2-3N type, and a second layer (second nitrided layer) formed continuously on the first layer, including a nitride having at least one kind of crystal structure out of hexagonal crystal structures of Cr2N, CrN, and M2-3N type, and a cubic crystal structure of M4N type, and being formed as a surface-nitriding-processed portion of the base material continuously in a depth direction from a surface of the base material.