Preparation and properties of water-soluble ceramic core for light alloy investment casting

Abstract

In this paper, a water-soluble ceramic core with quartz glass powder as the matrix material and K2CO3 as the binder was prepared by injection molding process. The effects of sintering temperature on the bending strength, porosity, solubility in water and solubility of the cores from the aluminum alloy castings were studied. The results show that when sintered below the melting temperature of K2CO3, the core porosity increases and the shrinkage decreases with the increase of sintering temperature. Instead, when sintered at 900 °C higher than the melting point of K2CO3, the core porosity decreases and the shrinkage rate increases. The bending strength of the core decreases with increasing sintering temperature always. Quartz glass and K2CO3 in the core promote each other's crystallization transformation and decomposition. The solubility of the core when it contacts with water is mainly affected by the porosity and the reaction products during the sintering process. When the sintering temperature is 800 °C, the two factors are better matched and the core has better comprehensive performance, the bending strength reaches 9.37 MPa and the water solubility and collapse performance is the best.