**4. Conclusions**

Reactively synthesized porous Ti3SiC2 compounds with di fferent pore sizes have the characteristics of high purity of MAX phase and laminar microstructure. The flexural stress–strain curves of porous Ti3SiC2 compounds exhibit two stages of elastic deformation and fracture, and the elastic deformation behavior shows a characteristic of kinking nonlinear elastic solid. The bending strength increases with decreasing the pore size for the synthesized porous Ti3SiC2 with approximately the same porosities and phase purities, and the change law between them follows the Hall–Petch equation. The flexural modulus of porous Ti3SiC2 has a power function relationship with the pore size. The reduction of the pore size of porous Ti3SiC2 improves the phase purity, strength and sti ffness while increasing its filtration accuracy.

**Author Contributions:** Conceptualization, Y.J. and Y.H.; methodology, Y.J.; validation, H.G.; formal analysis, X.L.; investigation, Y.J. and X.L.; resources, Y.J.; data curation, H.G.; writing—original draft preparation, Y.J.; writing—review and editing, Y.J. and Y.H.; supervision, Y.H.; project administration, Y.H.; funding acquisition, Y.J., X.L. and H.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China, gran<sup>t</sup> number 51971251, 51774336, 51604305.

**Acknowledgments:** The work is financially supported by the National Natural Science Foundation of China (No. 51971251, 51774336, 51604305).

**Conflicts of Interest:** The authors declare no conflict of interest.
