## 4 Results and Discussion  
According to the DSC curve in the thermogravimetric analysis (TG-DSC) shown in Figure 1, a distinct endothermic peak appears at 424.61 \({}^{\circ}\)C, representing the melting temperature of boron oxide (B\({}_{2}\)O\({}_{3}\)). At this temperature, boron oxide transitions from a solid to a liquid phase. The low melting point of boron oxide allows it to melt at relatively low temperatures, infiltrating the pores of the silicon oxide ceramic particles (as shown in Figure 3). This liquid-phase formation lowers the liquid-phase sintering temperature of the material, promoting densification of the ceramic at lower sintering temperatures. As shown in Figure 4, the shrinkage rates of silicon oxide ceramics with varying boron oxide (B\({}_{2}\)O\({}_{3}\)) content are illustrated. When no boron oxide is added, the shrinkage rate of the sample in the XY plane is 4.57%, while, in the Z direction, it is 6.25%. With the increase in boron oxide content, the shrinkage rate progressively rises. When the boron oxide content reaches 4 Wt%, the XY plane shrinkage rate increases to 16.40%, and the Z direction shrinkage rate reaches 17.03%. The shrinkage rate of silica ceramics increases linearly with the addition of boron oxide up to a concentration of 2%. Beyond this point, the shrinkage rate plateaus due to the saturation of reactive sites within the silica matrix. Moreover, as the boron oxide content rises, the gap between the shrinkage rates in the XY plane and the Z direction narrows. This indicates that, during the ceramic sintering process, boron oxide effectively improves the isotropic shrinkage characteristics, reducing internal stress and deformation caused by anisotropic shrinkage, thus enhancing the dimensional accuracy of the final product. The inconsistency between the XY plane and Z direction shrinkage rates is attributed to the principle of DLP printing. DLP forming technology uses layer-by-layer exposure, resulting in lower particle packing density between layers and relatively larger interlayer porosity compared to intralayer porosity. As a result, axial shrinkage (shrinkage perpendicular to the printing layer direction) is greater [24]. Figure 4: Shrinkage of ceramics with different boron oxide contents. Figure 3: Mechanism of action of boron oxide composite silicon oxide ceramics. The effects of different boron oxide contents on the apparent porosity and bulk density of the ceramic shell are illustrated in Figure 5. As the boron oxide content increases, the apparent porosity gradually decreases. Notably, when the boron oxide content rises from 0 Wt% to 3 Wt%, the apparent porosity decreases from 36.17% to 23.27%. This indicates that boron oxide can effectively reduce the apparent porosity of the ceramic material within a certain range. The reason for this is that boron oxide acts as a flux at high temperatures, enhancing the interaction between particles and promoting their gradual proximity, which results in reduced porosity and increased material density. However, when the boron oxide content is further increased to 4 Wt%, the apparent porosity slightly rebounds to 24.67%. This phenomenon is attributed to the excessive amount of boron oxide, leading to an overabundance of liquid phase at the grain boundaries. The excess liquid phase not only fails to promote further densification of the particles but also facilitates the formation of pores during the sintering process. As the boron oxide content increases, the bulk density rises from an initial value of 1.49 g/cm\({}^{3}\) to a maximum of 1.78 g/cm\({}^{3}\), indicating a significant enhancement in the densification process of the ceramic during this period. At a boron oxide content of 3 Wt%, the bulk density reaches its peak, suggesting optimal densification of the ceramic material at this point. However, when the boron oxide content increases to 4 Wt%, the bulk density slightly decreases to 1.71 g/cm\({}^{3}\), which is consistent with the increase in apparent porosity.