Three-dimensional (3D) printing of silica glass provides significant advantages for the fabrication of silica glass with complex structures. However, auxiliary support structures are generally needed due to the low stiffness and strength of green parts, which limits the flexibility of the structure design. It is imperative to increase the strength of the green part and remove the support structures for improving the molding capacity and printing quality. This study introduces an approach for 3D printing of silica glass with complex structures by digital light processing (DLP) based on the high-strength green parts, which exhibits superior molding capacity. By comparing three monomers of 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), and 4-hydroxybutyl acrylate (4-HBA), it was demonstrated that high photopolymerization reactivity is a key factor for improving the mechanical properties of green parts. Green parts printed with 4-HBA exhibit a combination of high modulus, high strength, and high conversion degree. Following heat treatment, these complex-structured green parts transform into dense, transparent silica glass. The specific compressive strength of silica glass with a lattice meta-structure reaches 4.94 × 10 4 N m kg −1 . This study enhances structural design flexibility in the 3D printing of silica glass, providing a novel perspective for future research.
Zirconia ceramics have shown a wide applicable prospect in dental prosthetics because it possesses excellent mechanical performance and biocompatibility. The rheological behavior and curing properties of zirconia stereolithography slurry were studied, as well as the microstructure of the green, pyrolyzed, and sintered body. Variquat CC-42 NS was proved to be effective for zirconia powder dispersing in photocurable resin (SP-RC700). The curing characteristic of slurry showed that the depth of penetration tended to increase with the solid loading. Finally, the zirconia all-ceramic crowns were fabricated via DLP-based stereolithography printer. Results showed that the particles were evenly distributed in the cured resin matrix without obvious agglomeration, and the interlayered structure disappeared after binder burnout. The sample with a major crystalline phase of tetragonal zirconia and a porosity of 10(1)% were obtained after sintering at 1550°C.
The effects of polyvinyl alcohol (PVA) on the slurry, granules, green bodies, and sintered varistors were investigated. The results showed that PVA inclusion as a binder not only influenced the mechanical properties of the granules, but also significantly impacted on the dispersibility of the slurry, the microstructure's uniformity, the compactness, and the element doping homogeneity of the varistors. These effects greatly affected the electrical properties, including the non-linear characteristics and the energy withstand capability. The optimal PVA concentration was found to be 0.7 wt%, resulting in varistors with excellent electrical properties: breakdown voltage gradient of 247.7 V/mm, nonlinearity coefficient of 41.0, residual voltage ratio of 1.71 under an 8/20 μs impulse current of 5 kA, and 100% pass rate under 2 ms rectangular waveform impulses of 900 A.
危险品化学品经营许可证（带存储）