【摘要】 采用添加成孔剂和冰冻-干燥法制备了具有不同气孔率的氮化硅多孔陶瓷,研究了该陶瓷在9.3GHz的微波介电性能。用SEM对微观形貌进行观察。结果表明,不同的成型工艺制备出具有不用孔结构的氮化硅多孔陶瓷,添加成孔剂制备的多孔陶瓷为较大的孔、洞分布在较致密的基体上;冰冻-干燥法制备的多孔陶瓷具有复合孔结构。对试样介电特性的研究表明,除了气孔率对介电常数和介电损耗有较大影响外,孔结构也是影响其介电特性的重要因素。更多还原

【Abstract】 Two different series of porous silicon nitride ceramics,whose volume fractions of porosity are from 0 to 0.6,were fabricated using two different preparation routes:(i) the addition of pore-forming agent,and(ii) freeze-drying processing.Effects of the amount of pore-forming agent and the concentration of water-based slurry on porosity were investigated.In order to predict and understand experimental dielectric properties-porosity relationships,porosity,porous structure and dielectric properties were evaluated separately for each series of materials.The results showed that besides the volume fraction porosity,the geometrical nature was also a major factor that influences the dielectric properties of the samples.更多还原