▎ 摘　　要

NOVELTY - The utility model claims a zinc-iron alloy plating layer for preparing chromium-free black conversion film plating layer structure, comprising a steel and zinc alloy substrate, and a zinc-iron alloy plating layer sequentially from inside to outside on the metal substrate, a chromium-free black conversion film and a hydroxyl graphene sealing layer. The utility model claims a zinc-iron alloy plating layer for preparing chromium-free black conversion film plating structure, according to GB/T 10125-2012 " artificial atmosphere corrosion test salt fog test " for neutral salt fog test 120h, the plating surface without white corrosion object. The plating layer structure does not contain chromium and cobalt, and has good corrosion resistance, can be used for replacing the current trivalent chromium passivation process.