Rapid synthesis of high‐strength porous Si ₃ N ₄ ceramics based on spontaneous solidification of multi‐phase particles

Abstract Porous silicon nitride ceramics have garnered significant attention due to their exceptional combination of structural and functional properties. Nevertheless, β‐grain growth is frequently accompanied by inhomogeneous shrinkage of the porous structure, rendering porous silicon nitride challenging in terms of both strength and application possibilities. Furthermore, the preparation process is also inefficient and energy consuming, which constrains its development. Here, we present a novel route that relies on the spontaneous solidification‐combustion process to fabricate high strength porous silicon nitride with a homogeneous microstructure. The spontaneous solidification of multi‐phase particles (Si‐Si 3 N 4 ‐Y 2 O 3 ) in the Isobam aqueous gelling system is successfully realized by the mechanochemistry for the first time. The rapid combustion reaction creates a homogeneous morphological structure consisting of inlaid acicular β‐Si 3 N 4 grains that exhibit excellent mechanical strength. It provides efficient and economical green manufacturing technology for preparing high‐performance structural porous ceramics based on complex multi‐phase gelling systems.