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–HfB 2 ) 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 SiO 2 –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 : HfB 2 ratio on the density, hardness, and homogeneity in the microstructural organization of the ceramic composite SiC–HfB 2 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–HfB 2 composites for a wide range of practical applications.