Porous Sintered Reaction‐Bonded Silicon Nitrides with Dual‐Sized Pore Channel using Presintered Si‐Additive Mixture Granules

Abstract

Porous sintered reaction‐bonded silicon nitrides (SRBSNs) with wide pore channels were fabricated using Si‐additive mixture granules. By increasing the strength through the presintering of the as‐spray‐dried granules, conventional uniaxial pressing was employed for the shaping while retaining the spherical granule morphology. The formation of wide intergranular (≥10 μm) and narrow intragranular (<1 μm) pore channels led to high porosity (≥50%) without the blending of fugitive. Both the widest pore channel (10.4 μm) and the highest permeability (κ = 0.3*10−12 m2) were measured using dm (mean diameter) = 76.5 μm granule.

Reaction bonded silicon nitride foams: The influence of iron disilicide on microstructure and mechanical strength

“…This newly developed and near net-shape fabrication procedure is capable of producing RBSN foams which benefit from controlled and high levels of porosity (between 41 vol% and 87 vol%), pore interconnectivity, ease of fabrication, and low production cost. It must be mentioned that there are only a few studies on the fabrication and characterization of RBSN foams [8][9][10][11]. The RBSN foams in these studies have been produced based on dry-processing techniques such as uniaxial pressing resulting in closed-cell structures with low levels of porosity (maximum porosity o60 vol%).…”

Macroporous Ceramics by Gelation–Freezing Route Using Gelatin

“…This section deals with Darcian air permeability of porous ceramics with different pore sizes and structures. [122][123][124][125] The solid line indicates theoretical permeability K ¼ f D p 2 /32 (f ¼ 0.85) for the case of unidirectional cylindrical pores penetrating in parallel. 10.…”

“…10. [122][123][124][125] The Darcian permeability, K, is determined from pressure drop and flow rate of air by the Darcy's law. [122][123][124][125] The solid line indicates theoretical permeability K ¼ f D p 2 /32 (f ¼ 0.85) for the case of unidirectional cylindrical pores penetrating in parallel.…”

“…[126,127] K values of Figure 10 are those adjusted from the reported values at the porosity of 0.85 using Equation 1 for comparison. [71,113,115,117,118,120,[122][123][124][125] The ratio of viscous contribution in total is estimated to be 60-90%. [71,113,115,117,118,120,[122][123][124][125] The ratio of viscous contribution in total is estimated to be 60-90%.…”