Solid-State Synthesis and Characterization of Hafnium Diboride Nanoparticles

Hafnium diboride (HfB2) nanoparticles have been prepared by a solid-state reaction of hafnium dioxide (HfO2), metallic magnesium (Mg) and sodium borohydride (NaBH4) at 700°C in an autoclave. The structure and morphology of the obtained product are investigated by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The transmission electron microscopy (TEM) image shows that the average size of HfB2 nanoparticles is about 30 nm. The oxidation behavior of HfB2 is studied by thermogravimetric analysis (TGA). It has good thermal stability and oxidation resistance below 380°C in air. Furthermore, the possible formation mechanism of HfB2 is also discussed.