Preparation of high-quality microspherical powders for TiO₂ coatings via spray drying

The quality of surface coatings considerably depends on the characteristics of the raw powders. To manufacture TiO₂ ceramic coatings with the desired tribological properties, utilizing high-quality spheroidized raw powders prepared via spray drying is a feasible and high-efficient approach. In this study, by adjusting the solid loading and dispersant content, an agglomeration-dispersion equilibrium is achieved in the optimized granulating slurry. This ensures the stable transportation of the slurry before the atomization process to form droplets, which has a substantial effect on the shape, size, and morphology of the microspheres. Subsequently, based on the thermophysical analyses (a mass loss induced by the removal of water or organic content is noted, and the differential scanning calorimetry results indicate organic degradation), reasonable post-treatment parameters are applied to enhance the strength of the microspheres without causing phase transformation or altering the microstructure. The use of green powders for fabricating TiO₂ and its homologous coatings is a rapid, low-cost, and energy-saving method.