At present, stereolithography 3D printing technology is widely used in ceramic additive manufacturing because of its high printing accuracy. Among them, the stereolithography ceramic slurry of non-oxide ceramics such as silicon carbide, silicon nitride, etc., has problems such as poor dispersion stability and low curing layer thickness because the incident light is difficult to penetrate and produce light curing reaction for printing high-solid-loading slurry. This is all because the refractive index and optical absorbance of the non-oxide ceramic printing material powder are relatively high. Therefore, printing and molding of high-solid-content non-oxide ceramics have become main challenges in stereolithography 3D printing, and the technology has attracted a large number of researchers to study its light-curing mechanism, powder control and other mechanisms. This paper systematically summarizes the research works of several non-oxide ceramics such as light-curing slurry preparation, light-curing molding, organic matter removal, and sintering densification. It also analyzes and discusses several methods of adjusting composition of photosensitive resin and modifying ceramic powder, and proposes innovative solutions to improve the slurry performance of non-oxide ceramics, optimize its light-curing printing, repair its densification defects and improve its performance. And the ultimate goal is to promote the advancement of high-precision preparation technology for light-curing additive manufacturing of large-size, complex-structure non-oxide ceramic parts.

Photopolymerization 3D printing method is an effective means for the manufacturing of ceramics with highly complex-shaped structures and exceptional performance. The printed samples need to undergo heat treatment such as debinding and sintering before becoming usable final ceramic parts in various industrial applications, and the debinding process has a great impact on the properties of the printed ceramic parts. In this study, effect of the debinding process on physical properties and mechanical performance of the cordierite ceramics prepared by DLP photopolymerization 3D printing was studied, and defect suppression strategy was established accordingly. The effects of debinding atmosphere and heating rate on surface cracks and material elemental distribution of ceramic samples were compared and analyzed. The microstructure, size shrinkage, relative density, and mechanical performance such as bending strength of the sintered samples were also studied. It is found that the debinding atmosphere has the most significant influence on the properties of the sintered samples, in which the surface cracks can be significantly reduced, and the relative density, and bending strength can be increased when the debinding process is conducted in argon atmosphere at the optimized heating rate of 1 ℃/min. After debinding and sintering, the cordierite ceramic samples with a relative density of (94.6±0.3)% and a bending strength of (94.3±3.2) MPa was obtained. In conclusion, this study provides a scientific basis and technical reference for fabrication and application of cordierite ceramics based on photopolymerization 3D printing method.

Because of low thermal conductivity and weak physical and chemical stabilities, traditional “phosphor in silicone” color converters are precluded from high-power white LED applications. All-inorganic bulk luminescence materials not only can circumvent organic encapsulation, but also have higher thermal conductivity. However, those bulk materials are high in cost and very difficult to be shaped into three-dimensional structures. Here, based on amorphous silica nanoparticles, a slurry, containing (Gd,Y)AG:Ce phosphor powders and can be polymerized under UV light, were developed. Bulk (Gd,Y)AG:Ce-silica glass composites were prepared successfully through photo curing, debinding in air and pressureless sintering. Under excitation of blue light, these luminescence glass-ceramics exhibit broadband orange emission peaking at 575 nm with internal quantum efficiency higher than 90%. Our results show that the interfacial reaction between (Gd,Y)AG:Ce and silica glass is very weak, and thus the former can be well embedded into bulk silica glass. Such all-inorganic color converters were further used to fabricate high-power warm white LEDs with correlated color temperature smaller than 4500 K, color rendering index higher than 75, and luminous efficiency of 74 lm·W ^-1. Luminescence saturation threshold of the as-fabricated laser lighting device is as high as 2.84 W·mm^-2, where its luminous flux can achieve 180 lm. Moreover, preparation of (Gd,Y)AG: Ce-silica glass composites is compatible to 3D printing technology, thus allowing the mass manufacturing of color converters with complex 3D structures, which may promote personalization and modularization of high-power white LEDs.

For ceramic stereolithographic (SL) additive manufacturing, the solid loading of ceramic photosensitive slurry plays an important role during the SL process. In this study, Al₂O₃ ceramics were fabricated by SL additive manufacturing from photosensitive Al₂O₃ slurries with various solid loadings, and the solid loading-property relationships of Al₂O₃ ceramic were performed. The effects of solid loading on not only the rheological behavior and curing property of the photosensitive Al₂O₃ slurry but also the microstructure and mechanical properties of the Al₂O₃ ceramic were investigated. The results showed that both the viscosity and shear stress increased with the increase of the solid loading. High viscosity was greater than the critical value for self-leveling during the SL process. The curing properties of photosensitive Al₂O₃ slurries were highly depended on the sold loading. Moreover, clear effects on the defect characteristics of Al₂O₃ ceramics manufactured from various photosensitive slurries were observed. These manufactured defects are critical for the mechanical behavior of Al₂O₃ ceramic. In addition, the relationship between rheological behavior and curing property of photosensitive Al₂O₃ slurry. Meanwhile, the resulting microstructure and mechanical properties of the Al₂O₃ ceramic were also illustrated. Inhomogeneous structure caused by high viscosity can lead to a sintered ceramic with poor strength. These findings provide fundamental understanding for SL additive manufacturing of ceramics.