The influence of ultraviolet radiation power on the structure formation of zirconium oxyhydroxide

Abstract

Metal oxide materials, including zirconium dioxide, are widely used in various modern technologies due to their high strength, chemical inertness, and thermal stability. Regulating the functional properties of these materials requires understanding the growth patterns of their nano- and microstructures, as well as the influence of various factors on structure formation. The main approaches to controlling the structure formation of these materials involve the use of powerful irradiation techniques, such as ultrasound, microwave radiation, and hydrothermal treatment. However, during the sol-gel synthesis stage, even weaker irradiation techniques have a significant impact on the course of structure formation processes and allow controlling the shape, size, and dispersion of crystalline structure characteristics. In the present study the effect of low-power ultraviolet (UV) radiation (electric power values of an irradiator are 15 and 30 W, reactor irradiance values are 600 and 1200 W/m2, respectively) on the structure formation of zirconium oxyhydroxide obtained by the sol-gel method at different ratios of formation rates (Vо) and growth rates (Vр) for nuclei has been investigated. Using thermal analysis (thermogravimetry and differential scanning calorimetry), X-ray phase analysis, high-resolution scanning and transmission electron microscopy, it has been established that UV irradiation, depending on the created illumination, has different effects on structure formation of zirconium oxyhydroxide. At Vo >> Vp, the main influence of UV irradiation consists in formation of faceted crystallites. At Vo  Vp and Vo << Vp, the influence of UV irradiation depends on the illumination created. Thus, at irradiator power of 15 W (illumination in the reactor is 600 W/m2), the changes primarily affect the size and faceting quality of crystallites in irradiated samples, especially pronounced at Vo << Vp. At irradiator power of 30 W (illumination in the reactor is 1200 W/m2), the formation of hierarchically structured materials is observed.