Reliability of diamond-reinforced Cu- and Al-matrix composites for thermal management under extreme climatic and mechanical conditions

The heat dissipation bottleneck induced by the high-power density of electronic devices is a core challenge that limits their operational stability and long-term reliability. Herein, diamond-Cu and diamond-Al composites (DCC and DAC) were systematically investigated with respect to material preparation, performance characterization, and reliability under extreme environments. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analyses indicate the presence of W-derived carbide-containing interfacial regions and close contact between the diamond particles and the Cu and Al matrices. Among the investigated particle-size distributions and diamond volume fractions, maximum thermal conductivities of 793.9 and 775.8 W m −1  K −1 were obtained for the DCC and DAC, respectively, while the DCC exhibited a maximum flexural strength of 405 MPa. The DCC underwent interfacial electrochemical corrosion in an acidic salt spray environment with a pH of 3.5, resulting in a maximum degradation of thermal conductivity of 26.8%. A gold-nickel protective coating with a thickness of at least 3 μm effectively suppressed micro-galvanic corrosion and significantly enhanced the corrosion resistance of both DCC and DAC. Furthermore, the composites exhibited excellent structural and thermal stability under high/low temperature, damp heat, and vibration conditions. Infrared thermal imaging tests verified their excellent heat dissipation performance. At 16.7 W cm −2 , the DCC and DAC reduced the heat-source temperature by 88.1 and 66.9 K, respectively, relative to 70Si/Al, with thermal stabilization reached within approximately 300 s. The developed composites demonstrated stable thermal performance under the prescribed laboratory environmental and mechanical loading conditions, indicating their potential for high-reliability electronic thermal-management applications.