摘要:
以CaO-B2O3-SiO2(CBS)玻璃粉体和Al2O3陶瓷粉体为原料,通过在CBS与Al2O3的质量比固定为50:50的玻璃-陶瓷复合材料中添加适量的Bi2O3作为烧结助熔剂,探讨了Bi2O3助熔剂对CBS/Al2O3复合材料的烧结性能、介电性能、抗弯强度和热膨胀系数的影响规律.研究表明:Bi2O3助熔剂能通过降低CBS玻璃的转变温度和黏度促进CBS/Al2O3复合材料的致密化进程,于880 ℃下烧结即能获得结构较致密、气孔较少的CBS/Al2O3复合材料.然而,过量添加Bi2O3将使玻璃的黏度过低,从而恶化CBS/Al2O3复合材料的烧结性能、介电性能及抗弯强度.当Bi2O3的添加量为CBS/Al2O3复合材料的1.5wt%时,于880 ℃下烧结即能获得最为致密的CBS/Al2O3复合材料,密度为2.82 g·cm-3,这一材料具有良好的介电性能(介电常数为7.21,介电损耗为1.06×10-3),抗弯强度为190.34 MPa,0~300 ℃的热膨胀系数为3.52×10-6 K-1.
Abstract:
CaO-B2O3-SiO2(CBS) glass powder and Al2O3 ceramic powder were used as the raw materials. Appropriate amount of Bi2O3, which was used as flux, was added into the glass-ceramic composites consisting of CBS and Al2O3 with a fixed mass ratio of 50:50. The effects of Bi2O3 flux on the sintering character, dielectric properties, bending strength and thermal expansion coefficient of CBS/Al2O3 composite were investigated. The results show that Bi2O3 flux can lower the transition temperature and the viscosity of CBS glass, which promotes the densifying of CBS/Al2O3 composites, and results in the CBS/Al2O3 composite which has relatively dense structure and less porosity can be prepared by sintering at 880 ℃. However, the excess addition of Bi2O3 will deteriorate the sintering character, dielectric properties and bending strength of CBS/Al2O3 composites for the viscosity of CBS glass is too low. When the additive amount of Bi2O3 is 1.5wt% of CBS/Al2O3 composite, the densest CBS/Al2O3 composite which has a density of 2.82 g·cm-3can be obtained by sintering at 880 ℃. This CBS/Al2O3 composite also has excellent dielectric properties (dielectric constant is 7.21, dielectric loss is 1.06×10-3), the bending strength is 190.34 MPa, and the thermal expansion coefficient from 0 to 300 ℃ is 3.52 ×10-6 K-1.
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