Comparison of microstructure and properties of diamond/copper Composites prepared by different sintering methods

ABSTRACT To meet the thermal management requirements of high-power electronic devices requiring high thermal conductivity and low thermal expansion, this study investigates the effects of different sintering processes on the microstructure and properties of diamond/copper composites. The results show that single-stage hot pressing (HP) leads to unsatisfactory dispersion uniformity of diamond particles within the copper matrix, accompanied by obvious particle agglomeration defects. By comparison, the samples prepared by hot oscillating pressing (HOP) exhibit improved microstructural uniformity; however, the interfacial bonding between copper matrix and diamond particles is weaker than that in HP-fabricated composites. Notably, the hybrid HOP+HP sintering process yields composites with the lowest porosity, the most uniform microstructure, and the strongest interfacial bonding. Consequently, the HOP+HP-processed composites exhibit the optimal overall performance, with a high relative density of 97.95%, an outstanding thermal conductivity of 717 W/(m·K), a low coefficient of thermal expansion (CTE) of 6.22×10 -6 K -1 at 50 ℃ and a superior flexural strength of 218 MPa. These findings demonstrate that the novel HOP+HP hybrid sintering process is an effective method for fabricating high density, high strength, and high thermal conductivity diamond/copper composites for advanced thermal management applications.