Abstract
Cylindrical disks composed of HfB2-26 vol%SiCf are successfully fabricated by combining the Self-propagating High temperature Synthesis (SHS) and Spark Plasma Sintering (SPS) processes. Specifically, HfB2 powders synthesized by SHS are mixed with SiC fibers and the resulting mixture is consolidated by SPS. The presence of SiC fibers was retained in the nearly full dense materials sintered at 1800 °C. The measured values of Vickers hardness, fracture toughness, flexural strength and elastic modulus at room temperature are 21.6±0.8 GPa, 6.2±0.5 MPa·m0.5, 429±45 MPa and 312±17 GPa, respectively. The obtained products are found to well resist to ablation, with weight losses below 0.25% when exposed to the most aggressive heat flux conditions (1250 W/cm2). A nozzle component of the desired shape and size is finally obtained for space propulsion applications after electrical discharge machining the SPS material.
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