Study of the High-Temperature Sintering Characteristics of Boron Oxide Composite Silicon-Based Ceramics

This paper explores the application of boron oxide (B2O3) as a sintering additive in silicon-based (SiO2) ceramics, focusing on its impact on the sintering process and resulting ceramic properties. Composite silicon-based ceramic shells with boron oxide content ranging from 0 to 4 Wt% were prepared using digital light processing (DLP) technology. This study examines the effects of boron oxide on sintering temperature, apparent porosity, shrinkage rates, and mechanical properties during high-temperature sintering. Experimental results indicate that, as boron oxide content increases, the shrinkage rate of the ceramic samples rises progressively, with shrinkage in the XY direction increasing from 4.57% to 16.40% and in the Z direction from 6.25% to 17.03%. Concurrently, the apparent porosity decreases with higher boron oxide content, ranging from a maximum of 36.17% to a minimum of 23.27%. Bulk density also improves from 1.49 g/cm3 to 1.78 g/cm3. The bending strength trend first rises and then declines, peaking at 15.39 MPa at a boron oxide content of 3 Wt%. X-ray Diffraction and Energy Dispersive Spectroscopy analyses confirm that the addition of boron oxide promotes the formation of beta-quartz and that its liquid-phase behavior at high temperatures aids in enhancing ceramic densification. This study demonstrates that an appropriate amount of boron oxide can effectively lower the sintering temperature of silicon-based ceramics while improving their mechanical properties, providing a theoretical foundation and practical basis for broader industrial applications.