颗粒整形对碳化硅陶瓷密封材料成型及烧结性能的影响

采用球磨对SiC粉体颗粒进行整形,并借助反应烧结制备SiC陶瓷密封材料,考察了颗粒整形对反应烧结SiC陶瓷成型、烧结性能、显微结构和力学性能的影响规律。结果表明,整形后的SiC颗粒的球形度高,粒径分布更为均匀;整形SiC粉体的振实密度和素坯密度明显提高,烧结体的显微结构更加均匀,主晶相为6H-SiC和Si,分布均匀,残炭很少;颗粒整形明显改善SiC陶瓷的成型性能及力学性能,当压力为15MPa时,整形后的SiC素坯密度为2.08g/cm~3,烧结体密度为3.06g/cm~3,抗弯强度和断裂韧性分别达到456MPa和3.87MPa·m1/2。

Effects of Particle Reshaping on Forming and Sintering of Silicon Carbide Ceramic Seals

Silicon carbide (SiC) powders were reshaped by ball grinder and made into sealing materials by reaction sintering.Effects of particle reshaping on forming,sintering behavior,microstructure and mechanical properties were studied.The reshaped silicon carbide powder has a higher degree of sphericity and more uniform particle size distribution.Both the tap density and green body density of the reshaped silicon carbide powder enhance apparently.The microstructure of the sintered body becomes more uniform with major crystalline phase 6H-SiC,better distributed Si and less residual carbon.Particle reshaping improves the ceramic forming and mechanical properties apparently.When the pressure is 15MPa,the pressing density and the sintered body density are tested as 2.08g/cm3 and 3.06g/cm3,with the flexural strength and fracture toughness reaching 456MPa and 3.87MPa·m1/2,respectively