Influence of pH and temperature parameters on the sol-gel synthesis process of meso porous ZrC nanopowder

Abstract

In this study, Zirconium carbide nanopowders were synthesized by the sol-gel method in the alcoholic system. Zirconium propoxide and phenolic resin were used as precursors of Zr and carbon, respectively. Sol was prepared in a four-component system of alkoxide, water, catalyst, and dispersant based on the sol-gel chemical process under acidic conditions. After the process of hydrolysis and the formation of gel, the initial powder was heat treated, and ZrC nanoparticles were formed. The impact of pH and temperature parameters on the synthesis process of these nanoparticles was evaluated. SEM/TEM, DTA/TG/XRD/FTIR/DLS analyses were used to assess the properties of the product. The results of sol preparation indicated that Zr-containing precursor particles less than 10 nm could be synthesized by controlling pH around 5. According to the FTIR data, Zr–O and Zr–C bonds were estimated to be 560 and 505 cm−1, respectively. Owing to the zirconium alkoxide hydrolysis and its condensation at 60 °C, Zr–O–C bonds were formed in the presence of the carbon phase. There is a possibility to achieve ZrC products at low temperatures under these conditions, as confirmed by the DTA analysis. DTA/TG analysis indicated that the primary particles of ZrC were generated around 1320 °C, as demonstrated by the X-ray diffraction pattern. BET analysis indicated a high surface area for the particles of approximately 153.42 m2/g, and that the surfaces of these particles were meso porous. SEM microstructure images showed that zirconium carbide particles were formed in a nanometer size range, and particle size distribution was performed within a narrow and uniform range. TEM images and their diffraction pattern reported the synthesis of crystalline carbide particles to be smaller than 50 nm.