The Characterization of Porous Sintered Reaction‐Bonded Silicon Nitride Ceramics Fabricated by Si‐Additive Mixture Granules

Porous sintered reaction‐bonded silicon nitride ceramics with dual‐sized pore channels were fabricated using granules consisting of a Si‐additive. A pressureless tapping method was used to maintain the spherical morphology of the weak spray‐dried granules. Emphasis was placed on the formation of wide pore channels (ϕ≥10 μm). In addition to the successful formation of wide pore channels between the granules, narrow channels formed inside the granules. The size of the wide channels (ϕ=5–20 μm) depended on the granule. On the other hand, the narrow channel size (ϕ<1 μm) remained the same regardless of the granule size.