锂辉石/碳化硅复相陶瓷材料的制备与性能  

Preparation and properties of spodumene/silicon carbide composite ceramic materials

作　　者：鲁媛媛 鹿桂花 周恒为 黄以能 Lu Yuan-Yuan;Lu Gui-Hua;Zhou Heng-Wei;Huang Yi-Neng(Xinjiang Laboratory of Phase Transitions and Microstructures in Condensed Matters,College of Physical Science and Technology,Yili Normal University,Yining 835000,China;National Laboratory of Solid State Microstructures,School of Physics,Nanjing University,Nanjing 210093,China)

机构地区：[1]伊犁师范大学物理科学与技术学院,新疆凝聚态相变与微结构实验室,伊宁835000 [2]南京大学物理学院,固体微结构物理国家重点实验室,南京210093

出　　处：《物理学报》2020年第11期277-283,共7页Acta Physica Sinica

基　　金：国家自然科学基金地区科学基金(批准号:11664042)资助的课题.

摘　　要：通过在碳化硅中添加高纯度近零膨胀材料b-锂辉石,采用无压液相烧结合成了锂辉石/碳化硅复相陶瓷.研究表明:适当添加b-锂辉石能促进碳化硅烧结,复相陶瓷体密度和杨氏模量随b-锂辉石含量的添加呈先升高后降低趋势,并在–150-480℃温度区间获得较低的热膨胀系数.研究结果对于开发热膨胀系数小、烧结温度较低的碳化硅复相陶瓷具有重要的参考意义.Silicon carbide(SiC) is widely used due to the lower coefficient of thermal expansion(CTE),high thermal conductivity and excellent mechanical properties.However,the self-diffusion coefficient of SiC relative to that of oxide ceramics is very low,it is difficult to sinter at lower temperature.The β-spodumene has ultra low or even negative thermal expansion coefficient combined with good thermal and chemical durability,which melts at 1423℃.Accordingly,the present study focuses on the use of β-spodumene as a flux at lower sintering temperature and the preparation of lower CET composite ceramics.The effects of spodumene on the sintering behavior,phase relations,thermal expansion and mechanical properties of spodumene/silicon carbide composites are discussed.A high pure β-spodumene LiAlSi2 O6 compound with nearly zero thermal expansion coefficient is synthesized via solid phase sintering.Spodumene/silicon carbide composites are fabricated by the adding 25,30,35 and 40 mass% synthesized β-spodumene powder to 75,70,65 and 60 mass% α-SiC matrix,respectively.Bothβ-spodumene and SiC are fabricated by conventional pressureless liquid sintering technique,and the batches are uniaxially pressed into discs and rectangular bars,then sintered at 1550℃ for 2 h in an Ar atmosphere.The results show that the SiC and β-spodumene do not react during sintering,and the β-spodumene changes from tetragonal phase into hexagonal phase,the cell volume has a considerable shrinkage.A certain amount of liquid phase can help to enhance the density,improve Young’s modulus and promote the sintering behavior of SiC.When the feedstock contains 35% β-spodumene,the Young’s modulus reaches to(204.2±0.5) GPa.Excess porosity is formed when liquid phase is too much during sintering,The Young’s modulus of the sample40 SP is(119.6 ± 0.5) GPa.It is determined that the Young’s modulus of these materials are affected by porosity and internal microcracks.This study indicates that the content of β-spodumene and porosity are the dominant fa

关 键 词：碳化硅 Β-锂辉石 热膨胀 杨氏模量 

分 类 号：TQ174.1[化学工程—陶瓷工业]