Composite member

A composite member comprising:

• a substrate composed of a composite material including a non-metal phase and a metal phase;
• and
• a metal layer that covers at least a portion of a surface of the substrate, wherein
• a metal included in each of the metal phase and the metal layer is mainly composed of Ag,
• a boundary region of the metal layer with the substrate includes Cu,
• a ratio of a content of Cu to a total content of Ag and Cu in the boundary region of the metal layer with the substrate is more than or equal to 7.99 atomic % and less than or equal to 15.93 atomic %,
• the boundary region includes Ti and Sn,
• a content of Ti in the boundary region is more than or equal to 0.1 atomic % and less than or equal to 2.0 atomic % when a composition of the boundary region is assumed to be 100 atomic %,
• a content of Sn in the boundary region is more than 0 atomic % and less than or equal to 3.0 atomic % when the composition of the boundary region is assumed to be 100 atomic %,
• the composite member is a heat radiation member,
• the non-metal phase includes a plurality of coated grains that include diamond grains and carbide layers coating and provided on each of the diamond grains, the carbide layers consist of at least one selected from the group consisting of SiC, TiC, ZrC, HfC, TaC, and Cr3C2,
• the content of non-metal phase to the composite material is more than or equal to 40 vol % and less than or equal to 90 vol %, and
• the metal layer includes a precipitate composed of Cu and is in contact with non-metal phase.