Manufacturing Method for Alloy Material, Alloy Material, Electrochemical Element, Electrochemical Module, Electrochemical Device, Energy System and Solid Oxide Fuel Cell

Provided is an alloy material including a metal oxide thin layer that can be formed using a simple method at low cost and can further suppress volatilization of Cr, which causes deterioration of a fuel cell, compared with a case where conventional expensive materials are used. Disclosed is a manufacturing method for an alloy material including a coating treatment step for coating a substrate made of a Fe—Cr based alloy with Co, and an oxidation treatment step for performing oxidation treatment on the substrate in a moisture-containing atmosphere after the coating treatment step.