Synthesis and Characterization of Hafnium Carbide Based Ceramics

Abstract

Hafnium carbide powder was synthesized by sol-gel polycondensation of hafnium chloride with citric acid. The starting materials were dissolved in water and mixed homogeneously on a hot plate until a precomposite gel was formed. Pyrolysis of the obtained gel resulted in formation of monoclinic hafnia and amorphous carbon, which after subsequent heat treatment transformed into hafnium carbide. Materials were analyzed by means of X-ray diffraction and electron microscopy investigations. The results showed that the obtained carbide powder was composed of nearly equiaxed particles of narrow size distribution. The obtained hafnium carbide powder was densified via spark plasma sintering (SPS) at 1950 oC using molybdenun silicide as sintering additive. Microstructure and mechanical properties of the obtained hafnium carbide ceramics were investigated.

Synthesis and Characterization of HfC/SiC Ceramic Nanoparticles

“…Hafnium carbide (HfC) has been investigated in the last ten years, due to its great potential in applications of ultra-high temperature, because has unique properties such as high melting point (3900°C), high absorbance values, surficial area, good thermomechanical and thermochemical properties. Hence, it is a promising material for tools, rocket nozzles, aircraft, spaceships and transmitters [1,2]. Feng et al [3] synthesized HfC/SiC nanocomposites via spark plasma sintering (R-SPS) of HfC and HfSi2 nanomaterials, using high energy ball mill during 2h in dry conditions, which were densified at 1750°C-1850°C by SPS during 10 minutes under vacuum axial pression of 40 MPa, obtaining a homogeneous microstructure.…”