Reaction Behavior, Microstructure, and Radiative Properties of In Situ ZrB 2 -SiC Ceramic Composites from a Si-Zr-B 4 C
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JMEPEG https://doi.org/10.1007/s11665-020-04990-9
Reaction Behavior, Microstructure, and Radiative Properties of In Situ ZrB2-SiC Ceramic Composites from a Si-Zr-B4C System Yong Li, Xiao Yang, Wei Wang, Yixiang Chen, and Jiangtao Li (Submitted February 9, 2020; in revised form June 2, 2020) 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. Keywords
heat dissipation, in situ, self-propagating high-temperature synthesis (SHS), ZrB2-SiC
1. Introduction As an important part of the ultra-high-temperature ceramics (UHTCs), ZrB2 has high melting point (3250 C), excellent high-temperature corrosion resistance, high hardness, superior thermal-electrical conductivity and good mechanical properties (Ref 1, 2). The materials have been commonly referred as the most potential candidates for thermal protection applications in extreme space environments such as sharp leading edges or nose cap on atmospheric reentry vehicles (Ref 3-7). The introduction of suitable content of SiC into ZrB2 matrix had been shown favorably for improving the anti-oxidation capability and mechanical strength (Ref 7). The mechanical mixing of commercially available ZrB2 and SiC powders generally has heterogeneous microstructure, and high agglomeration degree (Ref 8, 9), which usually results in poor mechanical properties in their sintering products. Therefore, in situ synthesis purity ZrB2-SiC composite powders has great potential in fabricating high-performance UHTCs. In previous studies, multiple methodologies including two-step calcination (Ref 10), reduction process (Ref 11), hybrid precursors (Ref 12) and selfpropagating high-temperature synthesis (SHS) (Ref 13) had been based on the in situ synthesis of ZS composite ceramics. Among them, the SHS has absorbed much attention due to the low cost, energy and time saving and simplicity of equipment (Ref 13). Specifically, SHS was capable of obtaining uniform Yong Li, Xiao Yang, Yixiang Chen, and Jiangtao Li, Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, PeopleÕs Republic of China; and Wei Wang, Songshan Lake Materials Laboratory, Dongguan 523808 Guangdong, PeopleÕs Republic of China. Contact e-mail: [email protected].
Journal of Materials Engineering and Performance
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