In order to enhance the degree of binding reaction of TiO2in titanium-containing ceramic glazes and prevent the reaction of its transformation into rutile to eliminate the yellowing phenomenon of the glaze surface, an apatite–TiO2composite opacifier (ATO) was prepared through the mechanical grinding of hydroxyapatite and anatase TiO2. The properties, opacification mechanism, and yellowing inhibition of the prepared ceramic glazes were studied. The results show that the ATO is characterized by a uniform coating of TiO2on the surface of the apatite and the formation of close chemical bonding between the apatite and TiO2. The ceramic glaze surface when using an ATO has a white appearance and excellent opacification performance. When an ATO was used, the L*, a*, and b* values of the glaze were 89.99, −0.85, and 3.37, respectively, which were comparable to those of a ZrSiO4glaze (L*, a*, and b*were 88.24, −0.02, and 2.29, respectively). The opacification of the glaze was slightly lower than that of the TiO2glaze (L* value was 92.13), but the appearance changed from yellow to the white of the TiO2glaze (b* value was 9.18). The ceramic glaze layer when using an ATO mainly consists of titanite, glass phase, and a small amount of quartz, and the opacification mechanism is the crystallization of the generated titanite. ATOs can play an active role in solving the critical problem that arises when TiO2replaces ZrSiO4as an opacifier.
Due to aerogel's network structure, specific surface area, and high porosity, SiO 2 aerogel has excellent thermal insulation and inferior mechanical properties. It is challenging to produce micro-objects and complex-shaped objects accurately by traditional manufacturing method because of the fragile mechanical properties. Here, we use 3D printing to fabricate SiO 2 aerogels. At the same time, we add opacifiers to reduce the aerogel's medium-high temperature thermal conductivity. The thermal conductivity of the SiO 2 aerogel printed in the experiment is as low as 0.028 W/(m·K) at room temperature. The aerogel doped with 10 wt% SiC has the best thermal insulation at medium-high temperatures. And the 3D printed aerogel doped with 10 wt% SiC has a compression performance of 1.19 MPa, which is more than 10 times better than the usual aerogel. This paper provides a method for creating micro-objects and complex-shaped objects with excellent medium-high temperature thermal insulation using Direct Ink Writing (DIW).
Silica aerogels exhibit considerable potential for thermal insulation applications owing to their low thermal conductivity. However, they generally possess poor mechanical properties and need to be mechanically enhanced while maintaining their low thermal conductivity. In this study, commercial fumed silica and methyltrimethoxysilane were used as the silica sources and water and ethanol were used as solvents to form a slurry. Consequently, silica aerogel monoliths (SAMs) were prepared through ambient drying without additional surface modification or solvent replacement. The resulting SAM maintained a typical nanopore structure and exhibited low density (0.24 g cm −3 ), shrinkage (4%), and thermal conductivity (0.046 W m −1 K −1 ). The slurry was impregnated with fiber blankets via roller pressing, and silica aerogel blankets (SABs) were prepared through thermal solidification of the slurry and ambient drying. The prepared SABs exhibited good flexibility and mechanical properties, facilitating their installation and application for thermal insulation and considerably reducing production cycles and costs. In addition, controlling the particle size and mass fraction of opacifiers decreased the high-temperature thermal conductivities of SABs owing to the nanopore structure and low shrinkage of SAMs, and the thermal conductivity of the optimized SAB at 800°C was as low as 0.054 W m −1 K −1 .
危险品化学品经营许可证（带存储）