## 4 Conclusions  
In this work, Si\({}_{3}\)N\({}_{4}\) ceramic was shaped using a stereolithography-based additive manufacturing technique. The slurry performance was intensively studied based on the analysis of rheological and curing ability measurements. Main conclusions are listed as follows,  
1. The presence of filler can significantly change the rheological behavior of pure monomers from Newtonian fluid to shear-thinning characteristic. Choosing the monomer with low molecular weight and taking the particle grading into consideration can obtain lower slurry viscosity.
2. The viscosity of Si\({}_{3}\)N\({}_{4}\) photocurable slurries were greatly affected by ambient temperature. With the temperature increased, the viscosity decreased obviously. Therefore, in this work the temperature was set as 25 \({}^{\circ}\)C which we think was suitable for machine handling.
3. The Si\({}_{3}\)N\({}_{4}\) slurry had lower curing ability when compared with oxide ceramic slurries. Because, besides the large refractive index of Si\({}_{3}\)N\({}_{4}\), it was measured that the absorbance of Si\({}_{3}\)N\({}_{4}\) powder also should not be ignored. According to the derivative equation from Beer-Lambert law, the cure depth is proportional to particle size. The coarse silicon powder with a particle size of 5 \(\upmu\)m was introduced to try improving curing ability but failed. It is because that silicon powder has a much higher absorbance. Using NPG2 PODA as crosslinking agent can obtain a higher cure depth than that of using HDDA at the same condition. This appearing as the probable cause of the higher molecular weight which NPG2 PODA possesses.  
Through the analysis of rheological and curing ability of slurries, the complex-shaped Si\({}_{3}\)N\({}_{4}\) ceramic could be manufactured using the stereolithography technology. The authors believe that this paper can give some thinking for the additive manufacturing of Si\({}_{3}\)N\({}_{4}\) or other non-oxide ceramics.  
Conceptualization, X.L. ([PERSON]) and J.Z.; Data curation, X.L. ([PERSON]) and N.L.; Formal analysis, X.L. ([PERSON]), Y.D., N.L. and R.M.; Funding acquisition, J.Z., H.X., X.L. ([PERSON]); Investigation, X.L. ([PERSON]); Methodology, X.L. ([PERSON]); Project administration, J.Z., H.X., X.L. ([PERSON]); Software, Y.D. and J.J.; Supervision, J.Z.; Visualization, X.L. ([PERSON]); Writing--original draft, X.L. ([PERSON]); Writing--review & editing, X.L. ([PERSON]) and J.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key Research and Development Program of China (2017 YFB-0310400), National Natural Science Foundation of China (No. 51572277, 51702340) and Shanghai Science and Technology Committee (17 YF1428800, 17 ZRI434800, 17 dz2307000). And the APC was funded by the National Key Research and Development Program of China (2017 YFB-0310400).  
The authors acknowledge the State Key Laboratory of High Performance Ceramics and Superfine Microstructure of Shanghai Institute Ceramics, Chinese Academy of Sciences, and Foshan Research and Development Center for Ceramics.  
Figure 8: The stereolithography of Si\({}_{3}\)N\({}_{4}\) ceramic architectures with complex shape and simple cuboid structures.