Synthesis and characterization of ZrB2 nanopowder by Sol-gel method

In the present study, ZrB2 nano powders were synthesized using sol-gel method. Zirconium alkoxide was used as the source of zirconium and boric acid as the source of boron. The size of precursor nanoparticle was controlled using the pH parameter inside the sol, and the formation of primary nuclei of ZrB2 phase and their crystallized amount were investigated using the temperature parameter. To evaluate the mechanism of product formation during the sol-gel process, DLS analysis showed that the size of precursor particle inside the sol at pH less than 5 was below 10 nm. Mixing of precursor particles at molecular level inside the sol was one of the important reasons in reducing the synthesis temperature of ZrB2 particles. FTIR analysis on chemical bonds showed that Zr-O-B bond was formed inside the gel powder.DTA analysis showed that the primary nuclei of ZrB2 particles were formed at a temperature of about 1400 °C. XRD observations proved that the primary nuclei of the ZrB2 phase crystallized and grew at a temperature of about 1500°C. Surface research revealed that the specific surface area of the synthesized ZrB2 particles is equivalent to 115 m2/g, and also the surfaces of these particles are porous, and the size of these porosities is in meso range. SEM analysis showed that the particle size of ZrB2 having homogeneous morphology is about 50 nm. TEM microstructural analysis revealed that ZrB2 particles were formed uniformly and orderly in very fine dimensions.