Effect of microwave drying on TiO2–Y2O3–ZrO2 composite ceramics and drying kinetic study

Abstract

TiO2–Y2O3–ZrO2 composite ceramics exhibit excellent abrasion resistance, corrosion resistance, and high-temperature resistance, making them vital structural-functional materials in ceramics and refractories. The key to preparing high-quality TiO2–Y2O3–ZrO2 ceramic powders lies in controlling the agglomeration rate, which can be optimized by choosing an appropriate drying method. This study utilized microwave drying techniques to dehydrate TiO2–Y2O3–ZrO2 ceramic powders. It was found that the average drying rate is proportional to initial masses, initial moisture contents and microwave heating powers. To describe the drying process, four models—the Quadratic, Wang and Singh, Modified Page, and Page—were employed. The best model for the drying process was the Modified Page model. The specimens were analyzed to assess the alterations in the samples pre and post-drying by scanning electron microscopy and Fourier transform infrared spectroscopy. The findings revealed that microwaves can hasten the drying process of TiO2–Y2O3–ZrO2 and enhance its spread. Utilizing Fick's second law, the effective diffusion coefficient was ascertained, showing an inverse proportionality to the sample mass, and a proportionality to the microwave heating power and initial moisture content. Using the Arrhenius exponential model, it was ascertained that the microwave drying process's activation energy stands at 13.81834 W/g. This paper demonstrates that microwave drying effectively achieves efficient drying and lays the theoretical and experimental groundwork for the microwave heating and drying of other powdered materials.