Plated steel material and method for manufacturing plated steel material

A coated steel product comprising a base steel and a coating layer including a Zn—Al—Mg alloy layer provided on a surface of the base steel, wherein the coating layer has a chemical composition composed of, in terms of % by mass:

• Zn at more than 65.00%,
• Al at more than 5.00% and less than 25.00%,
• Mg at more than 3.00% and less than 12.50%,
• Sn at from 0% to 3.00%,
• Bi at from 0% to less than 5.00%,
• In at from 0% to less than 2.00%,
• Ca at from 0% to 3.00%,
• Y at from 0% to 0.50%,
• La at from 0% to less than 0.50%,
• Ce at from 0% to less than 0.50%,
• Si at from 0% to less than 2.50%,
• Cr at from 0% to less than 0.25%,
• Ti at from 0% to less than 0.25%,
• Zr at from 0% to less than 0.25%,
• Mo at from 0% to less than 0.25%,
• W at from 0% to less than 0.25%,
• Ag at from 0% to less than 0.25%,
• P at from 0% to less than 0.25%,
• Ni at from 0% to less than 0.25%,
• Co at from 0% to less than 0.25%,
• V at from 0% to less than 0.25%,
• Nb at from 0% to less than 0.25%,
• Cu at from 0% to less than 0.25%,
• Mn at from 0% to less than 0.25%,
• Li at from 0% to less than 0.25%,
• Na at from 0% to less than 0.25%,
• K at from 0% to less than 0.25%,
• Fe at from 0% to 5.00%,
• Sr at from 0% to less than 0.50%,
• Sb at from 0% to less than 0.50%,
• Pb at from 0% to less than 0.50%,
• B at from 0% to less than 0.50%, and
• impurities,
• wherein, in a backscattered electron image of the Zn—Al—Mg alloy layer, obtained by polishing a surface of the coating layer to ½ of a layer thickness, and observing the surface at a magnification of 100× with a scanning electron microscope, Zn/Al/MgZn2 ternary eutectics are present, and an average value of a cumulative circumferential length of the Zn/Al/MgZn2 ternary eutectics is from 100 to 300 mm/mm2.