Y_(2)O_(3)对高热导率Si_(3)N_(4)陶瓷显微结构和性能的影响

Effect of Y_(2)O_(3) on Microstructure and Properties of High Thermal Conductivity Si_(3)N_(4) Ceramics

以氧含量相对较高的“平价”Si_(3)N_(4)粉体(氧含量1.85%(质量分数))为原料,Y_(2)O_(3)-MgO作为烧结助剂,制备低成本高热导率Si_(3)N_(4)陶瓷,研究Y_(2)O_(3)含量对Si_(3)N_(4)陶瓷致密化、显微结构、力学性能及热导率的影响。结果表明,适当增加Y_(2)O_(3)的加入量不仅可以促进Si_(3)N_(4)陶瓷的致密化和显微结构的细化,还有助于晶格氧含量的降低和热导率的提升。Y_(2)O_(3)含量为7%(质量分数)的样品在1900℃烧结后的综合性能最佳,其相对密度、抗弯强度、断裂韧性和热导率分别为99.5%、(726±46)MPa、(6.9±0.2)MPa·m^(1/2)和95 W·m^(-1)·K^(-1)。

Cost-effective fabrication of high thermal conductivity Si_(3)N_(4)ceramics was realized by using low-cost Si_(3)N_(4)powder with relatively high oxygen content(1.85%(mass fraction))as raw material and Y_(2)O_(3)-MgO as sintering additives.The effect of Y_(2)O_(3)addition on the densification,microstructure,mechanical properties and thermal conductivity of Si_(3)N_(4)ceramics was investigated.The results show that properly increasing the addition of Y_(2)O_(3)not only promotes the densification and microstructure refinement of Si_(3)N_(4)ceramics,but also contributes to the decrease of lattice oxygen content and the improvement of thermal conductivity.The sample containing 7%(mass fraction)Y_(2)O_(3)sintered at 1900℃has the optimum comprehensive properties,and its relative density,flexural strength,fracture toughness and thermal conductivity are 99.5%,(726±46)MPa,(6.9±0.2)MPa·m^(1/2)and 95 W·m^(-1)·K^(-1),respectively.