Coating structure, impeller, compressor, metal part manufacturing method, impeller manufacturing method, and compressor manufacturing method

A coating structure comprising:

• a chemical conversion layer that contains magnesium as a main component and is made of a phosphate-coated film and is formed in a manner of covering a surface of a base material which is made of a magnesium alloy containing at least one kind of element selected from a group consisting of gadolinium, terbium, thulium, and lutetium;
• and
• a plating layer that is made of a nickel-based alloy and is formed in a manner of covering the chemical conversion layer.

A metal part manufacturing method comprising:

• a step of forming a chemical conversion layer by performing chemical conversion treatment in a manner of covering a surface of a base material which is made of a magnesium alloy containing magnesium as a main component;
• and
• a step of forming a plating layer which is made of a nickel-based alloy in a manner of covering the chemical conversion layer.