Reaction Behavior, Microstructure, and Radiative Properties of In Situ ZrB2-SiC Ceramic Composites from a Si-Zr-B4C System

The present work focuses on the in situ self-propagating high-temperature synthesis (SHS) of ZrB2-SiC (ZS) ceramic composites in a Si-Zr-B4C system. The reaction process characteristics, microstructure and radiative properties of products were investigated. The thermal conductivity of ZS/acrylic composite coating filled with 40 wt.% ZS is 1.77 W/m K, which is ninefold enhancement in comparison with neat acrylic coating. In addition, in situ ZS/acrylic composite coatings showed an excellent increase in infrared emissivity up to 0.93 for 45 wt.% in situ ZS content, which was nine times more than bare aluminum alloy substrate. The produced coatings remarkably increased the heat dissipation performance of an aluminum alloy tube by 17.9%, implying a promising prospect for real passive heat dissipation applications.