Preparation study for the low thermal expansion spodumene/mullite composites

Abstract In this work, spodumene/mullite ceramics with low thermal expansion were successfully prepared from spodumene, quartz, talc, and clay. The effects of spodumene content and sintering temperature on the mechanical properties of spodumene/mullite ceramics were investigated. The formed phases were then detected by X‐ray diffraction analysis and the microstructures of the sintered bodies were determined by scanning electron microscopy. The interaction effects of the spodumene content and sintering temperature on the apparent porosity and bulk density were studied by response surface methodology. The results demonstrate that an appropriate sintering temperature and spodumene content can promote densification, improve the mechanical properties, and reduce the coefficient of thermal expansion (CTE) of spodumene/mullite ceramics. At the spodumene content of 40 wt.%, the sintering temperature of 1270°C, and the holding time of 90 min, the bending strength was 60.45 MPa, the CTE was 1.73 × 10 ^–6 /°C (α _{[25–650°C]} < 2 × 10 ^–6 /°C), the bulk density was 2.28 g cm ^‐3 , and the apparent porosity was 0.43%. Therefore, this study was of guiding significance for reducing the production cost of spodumene low thermal expansion ceramics and improving product quality.