Porous Si₃N₄ ceramics were prepared via a controlled gel-casting process followed by gas pressure sintering with 8 wt.% Y₂O₃ and Al₂O₃ additives. The gel-casting parameters including slurry pH value, AM: MBAM ratio, degassing procedure, drying condition and decarbonize process were optimized, and the effects of different Y₂O₃: Al₂O₃ ratios on the microstructure and properties of the Si₃N₄ ceramics were investigated. With an optimized gel-casting process, a high solid loading of 46.5 vol.% was achieved, and as the Y₂O₃ content decreased from 6 to 1 wt.%, the porosity of Si₃N₄ ceramics declined from 36.3 to 27.5% while the β-Si₃N₄ phase content reduced from 38.9 to 15.0%. The bending strength and elastic modulus of the ceramics varied with different Y₂O₃: Al₂O₃ ratios and were influenced by the porosity as well as the tailored interlocking structure of elongated β-Si₃N₄ grains. The Si₃N₄ ceramics also exhibited low and stable dielectric constants.

多孔Si ₃ N ₄陶瓷是通过受控的凝胶浇铸工艺制备的，然后用8 wt％的Y ₂ O ₃和Al ₂ O ₃添加剂进行气压烧结。优化了浆料的pH值，AM：MBAM比，脱气步骤，干燥条件和脱碳工艺等凝胶浇铸参数，不同的Y ₂ O ₃：Al ₂ O ₃比对Si ₃的微观结构和性能的影响。研究了N ₄陶瓷。通过优化的凝胶浇铸工艺，获得了46.5 vol。％的高固含量，而Y ₂ø ₃含量降低为6〜1重量％，Si的孔隙率₃ Ñ ₄陶瓷从36.3下降到27.5％，而β型Si ₃ Ñ ₄相含量降低从38.9％至15.0％。的弯曲强度和陶瓷的弹性模量不同的变化Ý ₂ ö ₃：AL ₂ ö ₃比和由孔隙率以及细长β-Si的定制互锁结构被影响_3个Ñ ₄晶粒。Si ₃ N ₄陶瓷还表现出低而稳定的介电常数。