High Entropy Boride-SiC Composite: Synthesis, Characterization and Thermo-oxidative behaviour

05 July 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Silicon carbide reinforced multicomponent high entropy diboride-based particulate composites (HEB-SiC) were fabricated by spark plasma sintering at 1800°C using diboride powders prepared from boro-carbothermal reduction method to investigate the influence of the addition of SiC (SiC content = 20, 40 vol%) on the microstructural evolution, oxidation, and exposure to arc-jet behaviour was reported. SiC has been found to improve the densification of pristine diboride, with attainment of a maximum of ~ 98% relative density for SiC content of 40 vol%. A percolating network of SiC grains in the HEB matrix was observed in the case of composites with 40% volume fraction of SiC. The oxidative behavior at 1400°C in air revealed excellent improvement of oxidation resistance of 20 vol% SiC reinforced composite as compared to other sintered specimens. Arc-jet testing on 20 vol% SiC reinforced composite revealed no structural deformity with very minute-scaled formation of surface oxide layers. These results indicate that the addition of 20 vol% SiC in a diboride matrix can contribute to the optimal preparation of high entropy diboride-based ceramics with balanced mechanical properties with improved oxidation resistance.

Keywords

High entropy diboride
silicon carbide
composites
thermal conductivity
oxidation behaviour
ultra-high temperature ceramics

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