Dynamics characteristics and microstructure evolution of Sc2O3-ZrO2 ceramic powders during microwave drying

Sc2O3-ZrO2 ceramic powders has excellent features such as high-temperature resisting, abrasion resisting, and erosion resisting, which makes it rapidly become a new high-performance ceramic material. The appropriate drying method can effectively reduce the agglomeration and coarsening of Sc2O3-ZrO2 ceramic powder, which is beneficial for obtaining finer ceramic powders. Microwave heating was used to dry Sc2O3-ZrO2 ceramic powders, and the influence laws of kinetic parameters of initial water contents, initial masses, and microwave powers on drying process were discussed by using the single factor experimental method. The experiment results demonstrated that average desiccation rate grew with increase of the three variables. Drying efficiency increases with increasing initial masses and initial water contents, while the opposite is true for microwave powers. The experimental data of Sc2O3-ZrO2 ceramic powders drying were fitted and analyzed by Two-term exponential, Page, Quadratic, and Simplified Fick's diffusion models, and it was discovered that the Quadratic model could accurately describe the Sc2O3-ZrO2 ceramic powders desiccation progress. To evaluate the variations of the Sc2O3-ZrO2 ceramic powders before and after desiccation, they were characterized using FT-IR and FE-SEM, and the outcomes showed that microwaves can dry Sc2O3-ZrO2 ceramic powders quickly and efficiently and improve their dispensability. The effective diffusion coefficient was computed by Fick's second law, which increased and then decreased with the growth of the initial masses, initial water contents, and microwave powers of Sc2O3-ZrO2. For instance, the effective diffusion coefficients for different initial masses are 8.3917 x 10-5, 9.4614 x 10-5, 1.2515 x 10-4, 1.2267 x 10-4, and 9.9496 x 10-5 m2/s, correspondingly. The drying activation energy was computed using the Arrhenius index model to be -16.095 g/W (R2 reaching 0.99999). In this article, we combine experimental research with theoretical calculations to explore the effects of initial mass, initial moisture content, and microwave heating power on drying rate and microwave energy efficiency, which provides an important theoretical foundation and referential value for the actual desiccation progress of other ceramic powders.