Preparation of homogeneous SiC coating on diamond particles by magnetron sputtering for diamond/Al composites with high thermal conductivity

Diamond SiC Diamond Aluminum heatsink heat spreader

Diamond/Al composites are attractive for next-generation electronic packaging owing to their low density, high thermal conductivity, and tunable coefficient of thermal expansion. However, their performance is often degraded by Al₄C₃ formation at the diamond/Al interface, which is prone to hydrolysis and severely reduces thermal conductivity in humid environments. Conventional approaches such as alloying or carbide coatings (TiC, WC, ZrC) can suppress Al₄C₃, but they frequently introduce intermetallics that lower matrix conductivity and worsen phonon mismatch.

Recently, a nanoscale Si preset layer was deposited on diamond by magnetron sputtering, annealed in vacuum, and subsequently infiltrated with Al. The Si layer exhibited temperature-dependent phase transitions from amorphous Si → crystalline Si → crystalline Si + SiC → SiC (750–1300 °C). 

These transitions governed the interfacial products and heat transfer. When the layer consisted mainly of amorphous/crystalline Si, the interface was diamond–Al₄C₃–Al. In contrast, when dominated by SiC, the interface evolved into diamond–SiC–Al₄C₃ (minor, dispersed)–Al, yielding a thermal conductivity of 723 W·m⁻¹·K⁻¹. The resulting serial/parallel hybrid interfacial network (SiC/Al, SiC/Al₄C₃, SiC/diamond) significantly enhanced phonon transport.

This study demonstrates that controlled Si-to-SiC conversion enables chemically bonded, nanoscale interlayers that both inhibit Al₄C₃ and improve thermal conductivity, offering new insights into interface engineering for high-performance diamond/Al composites.

#Diamond SiC #Diamond Aluminum heatsink heat spreader