Plated steel sheet and method producing same

A plated steel sheet comprising:

• a steel sheet;
• and
• an alloy plating layer formed on a surface of the steel sheet,
• wherein the alloy plating layer consists of, in mass %, Cr:
• 5 to 91%, Fe:
• 0.5 to 10%, and the balance:
• Ni and unavoidable impurities,
• wherein the Ni concentration in the alloy plating layer gradually decreases from an outermost surface of the alloy plating layer to a side of the steel sheet,
• wherein a ratio of the Ni concentration to the Cr concentration is Ni/Cr>1 in an area extending 300 nm or more from the outermost surface of the alloy plating layer,
• the Fe concentration in the alloy plating layer gradually decreases from the side of the steel sheet to the outermost surface of the alloy plating layer,
• the Fe concentration in an area in a range of 10 nm in depth from the outermost surface of the alloy plating layer is 0.5% or less,
• a total thickness of a Cr—Fe-containing alloy layer formed in the alloy plating layer and containing Cr and Fe is 500 to 2000 nm, and
• a total amount of the alloy plating layer deposited to the steel sheet is 4.5 to 55.5 g/m2,
• wherein a deposited amount of Cr plating in the alloy plating layer is 3.5 to 15.0 g/m2,
• wherein a deposited amount of Ni plating in the alloy plating layer is 3.0 to 26.7 g/m2, and
• wherein a ratio of the deposited amount of Cr/Ni plating in the alloy plating layer is 0.9 to 5.0.