Particle size gradation design and performance enhancement of quartz cores for precision casting

Abstract

This study proposes an approach for the design of gradation plans via the establishment of mathematical models for particle gradation, enabling control over the particle gradation of different sizes of SiO₂. Silica-based ceramic cores were produced follow the above strategy for precision casting, and the impact of particle gradation and sintering regimes on the shrinkage rate and relevant mechanical properties of the silica-based ceramic cores were investigated. The results suggest that an optimal gradation plan can effectively enhance the density of silica-based ceramic cores, thereby influencing the shrinkage rate and mechanical properties at both room and elevated temperatures. The shrinkage rate of the silica-based ceramic cores is influenced by the chosen gradation particle size range of the silica; the sintering regimes have notable effects on mechanical properties of the silica-based ceramic cores. The performance data of the samples demonstrate the efficacy of applying the gradation plan to the B₆₀ samples with an average particle size of 60 µm in the largest grade. After undergoing a final sintering temperature at 1160°C and holding for 5 h, the shrinkage ratio could be limited to 1.33%, the room temperature bending strength reached 15.0 MPa, and the high-temperature bending strength could be enhanced to 37.6 MPa. These findings present a significant reference values for the production of single-crystal hollow blades.