Spark Plasma Sintering-Reactive Synthesis of SiC and SiC–HfB2 Ceramics Based on Natural Renewable Raw Materials

An original method for producing a ceramic material based on silicon carbide (SiC) and its composite with the addition of hafnium diboride (SiC–HfB2) from organic raw materials of natural origin is presented. The originality of the method is in the use of the spark plasma sintering-reactive synthesis of a powder mixture based on the product of thermal oxidative treatment of rice husk (RH). The formation of a ceramic product based on SiC occurs through an in situ reaction in the SiO2–C system constituting the basis of RH, which is initiated by spark plasma heating. The phase formation and structure formation of ceramics have been studied by X-ray diffraction analysis, Raman spectroscopy, and scanning electron microscopy; in addition, the physical and mechanical properties of ceramic materials have been reported. The influence of the SiC : HfB2 ratio on the density, hardness, and homogeneity in the microstructural organization of the ceramic composite SiC–HfB2 has been demonstrated. The unconventional method represents an obvious prospect for an efficient and cost-effective approach to obtaining high-quality SiC ceramics and its high-temperature SiC–HfB2 composites for a wide range of practical applications.