Abstract: A highly efficient heat exchanger member is realized by providing, to a metal surface, a characteristic that is not found in the metal itself with a coating film excelling in thermal conductivity. A heat exchanger member is made of metal, and includes a carbon-containing oxide film (112B) provided on the metal surface and having fine concave-convex portions (112C). An average spacing between apexes of convex portions of the fine concave-convex portions (112C) is greater than or equal to 40 nm and less than or equal to 120 nm, and an average value of differences in height between apexes of adjacent convex portions and bottom points of concave portions is greater than or equal to 30 nm and less than or equal to 250 nm.

Abstract: A heat exchanger member, a heat exchanger, a heat exchanger, and a cooling system that are highly efficient are realized by providing, to a surface of a metal in contact with a refrigerant, of a heat exchanger used for a cooling unit and a heat dissipation unit, characteristics not found in the metal itself with a coating film excelling in thermal conductivity and excelling in wettability with the refrigerant. A heat exchanger member made of metal having a surface that comes into contact with a refrigerant when a heat exchanger is operated includes a metal oxide film provided on the surface, having protrusions, and containing crystalline carbon.