Porous Si₃N₄ Ceramics Prepared via Nitridation of Si Powder with Si₃N₄ Filler and Postsintering

Abstract

Porous silicon nitride (Si3N4) ceramics with high porosity were prepared via nitridation of Si powder, using Si3N4 as filler and Y2O3 as sintering additive. After nitridation, samples with high Si3N4 filler content showed high porosity, low flexural strength, and low grain size. A porosity of 50–62% a flexural strength of 16–49 MPa were obtained. After postsintering at 1750°C, sample with Si3N4 filler content of 50% exhibited a bimodal grain size distribution of elongated β‐Si3N4 grains with high aspect ratio embedded in fine‐grained matrix. Porous Si3N4 ceramics with a porosity of 48–60% and a flexural strength of 100–145 MPa were obtained.

Synthesis, Characterizations and <i>in Vitro</i> Assessment of the Cytotoxicity and Genotoxicity of Novel Silicon Nitride-Based Porous Ceramics

“…Whereas the samples S-5 and S-10 with lower porosity (10.7 vol% and 20.3 vol%) demonstrated cytotoxicity in the range from 14.9% to 21.3%, the ceramic sample S-20 with the highest porosity (36.4 vol%) had negligible cytotoxicity (<10%). These observations are in agreement with the results of Dongxu et al that Si 3 N 4 ceramics with high porosity are promising candidates for bio-applications [21].…”

“…Porous Si 3 N 4 -based ceramics with high porosity is a promising candidate for engineering applications, such as hot gas filter, heat insulators, catalyst carriers, bioreactors, medical implants, etc. [21,22]. For industrial applications several kinds of porous Si 3 N 4 -based ceramics with different mechanical, thermal and chemical properties were prepared by different fabrication routes [20,[23][24][25][26][27][28].…”

Effect of Y2O3additive on nitridation of diamond wire silicon cutting waste

“…43 The nitrogen can react with silicon through cracks, and then Si 3 N 4 is formed through reactions (10) and ( 11) at a relatively low temperature. It has been established [44][45][46] that α-Si 3 N 4 is a low-temperature metastable phase, and β-Si 3 N 4 is a high-temperature stable phase. Therefore, Y 2 O 3 additive can promote the formation of β-Si 3 N 4 through accelerating the nitridation of silicon at high temperature (1500 • C).…”

Cerâmicas de nitreto de silício contendo óxidos de silício, estrôncio e alumínio para substituições ósseas

“…Estas cerâmicas amplificaram sua utilização em aplicações industriais com diferentes propriedades mecânicas, térmicas e físicas (127) , como por exemplo, em filtro de gás quente, isoladores de calor, suportes catalisadores, biorreatores, implantes médicos, entre outras (128,129) , mas já usadas como espaçadores intervertebrais com bastante sucesso (130) .…”

“…Também foi constatada por meio de testes biológicos, melhor osteointegração do nitreto de silício em comparação com a alumina (131,132) . Estudos (129) relataram ótimos resultados na utilização de espaçadores intervertebrais de cerâmicas de Si3N4 sinterizado em pacientes com degeneração espinhal. Outros experimentos relataram que parâmetros como morfologia, crescimento e proliferação celular resultantes de testes in vitro com nitreto de silício de superfície polida são bastante semelhantes àqueles devido à presença do dióxido de titânio (TiO2) (130) .…”