Polymer‐Coated Ceramics Versus Admixed Ceramic‒Polymer Feedstocks for Injection Molding: Rheological and Thermal Analysis

Polymer‐coated ceramic powders (PCCPs) prepared via a thermally induced phase separation (TIPS) process have emerged as a promising alternative for enhancing the processability and mechanical properties of highly filled ceramic polymer compounds. This study investigates the performance of PCCP, specifically alumina particles coated with polybutylene terephthalate (PBT), compared to conventional admix compounds prepared through melt‐mixing. The research explores the viscosity, flowability, packing efficiency, and thermal stability of PCCP at 50 and 60 vol.% solids loadings. The results indicate that PCCP exhibits significantly lower viscosity across all shear rates, with a 54.1% reduction at 1000 s ‒1 compared to admixes at 50% loading, which can help to improve mold filling behavior and reduce processing defects. Additionally, PCCPs demonstrate enhanced powder flowability, as evidenced by a lower Hausner ratio (1.15 for 50% PCCP vs. 1.56 for alumina particles) and high pycnometer density (2.81 g/cm 3 ), suggesting good packing efficiency. At 60% loading, all compounds exhibited significantly increased viscosity, indicating the challenges associated with high solids loading, while PCCP maintained improved rheological performance under these conditions. The findings highlight PCCPs as a better alternative to conventional, ad‐mixed ceramic‒polymer compounds, offering enhanced flow characteristics at industrially relevant shear rates, better packing, and improved thermal behavior, making it a viable option for high‐performance ceramic injection molding applications.