Preparation of HfSiO4 via Non-Hydrolytic Sol-Gel method at low temperatures

Hafnon (HfSiO 4 ) can be applied in electronics, dielectric films , refractory materials , and many other critical application areas. To explore an efficient preparation process of HfSiO 4 , a novel non-hydrolytic sol-gel (NHSG) method was used to synthesize high-purity HfSiO 4 in this study. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), thermogravimetric differential scanning calorimetry (TG-DSC), Fourier transform infrared spectroscopy (FT-IR), and infrared thermal imaging (ITI) were used to investigate the synthesis temperature and mechanism of HfSiO 4 and the effects of process parameters on its synthesis efficiency. The results show that the prepared sols undergo a highly reactive non-hydrolytic polycondensation reaction at room temperature. High temperature reflux or long time aging step is not necessary to form the strong Hf- O -Si bonds. Furthermore, with the introduction of the mineralizer agent LiF, the synthesis temperature of HfSiO 4 can be drastically reduced, and the HfSiO 4 with high purity can be synthesized at low temperatures. A moderate molar ratio of silicon to hafnium (Si:Hf) and molar concentration of the solution contribute to improve the synthesis efficiency of HfSiO 4 , and the purity of HfSiO 4 products can reach up to 98.12 %.