High-thermal-conductivity low-expansion ultrathin diamond-metal-based composite material as well as preparation method and application thereof

The invention discloses a high-thermal-conductivity low-expansion ultrathin diamond-metal-based composite material as well as a preparation method and application thereof. The high-thermal-conductivity diamond/metal-based composite material comprises core-shell structure doped diamond and a metal-based material, wherein the core-shell structure doped diamond comprises diamond and a diamond surface modification layer; the diamond surface modification layer sequentially comprises a diamond transition layer and a doped diamond shell layer from inside to outside; and the thickness of the diamond-metal-based composite material is 0.1-1 mm. The preparation method comprises the following steps: by adopting a gas pressure assisted infiltration process technology, taking high-purity gas as a pressure source, and acting on the molten liquid metal-based surface, thereby implementing high-density compounding of the diamond and metal-based material. The high-thermal-conductivity low-expansion ultrathin diamond-metal-based