SiC的添加对AlN/Mo/SiC复合陶瓷的制备和性能影响探究  

Effect of SiC on Fabrication and Properties of AlN/Mo/SiC Composite Ceramics

作　　者：董茜[1] 杨志民[1] 

机构地区：[1]北京有色金属研究总院先进电子材料研究所,北京100088

出　　处：《稀有金属》2011年第6期904-908,共5页Chinese Journal of Rare Metals

基　　金：北京有色金属研究总院创新技术基金资助项目

摘　　要：以氮化铝(AlN),钼(Mo),碳化硅(SiC)为原料,采用放电等离子烧结的方式,在1700℃,30 MPa制备出致密度高达98.5%的SiC添加的AlN/Mo复合陶瓷。采用XRD,FESEM,Agilent4284型LCR自动测试仪,网络分析仪及激光导热仪对样品的微观形貌,导电性能,介电性能和热导率进行了测试分析。研究结果表明:采用放电等离子烧结工艺,在较低的温度下可以制备出组织致密均匀的AlN/Mo/SiC复合材料,但随着SiC添加含量的增加,当SiC的体积含量占到总体的60%时,复合材料的致密度又会出现明显的下降。添加SiC后,相对于AlN/Mo复合陶瓷,复合材料的电阻率得以进行有效的控制,不会出现非线性突变—渗流现象,而是在一定的范围内缓慢下降。在26.5～40.0 GHz下复合材料的介电常数和介电损耗均随着SiC含量的增加而增加。复合材料的热导率随着SiC含量的增加而下降:当致密度高于某临界值时,其热导率主要受SiC含量及其分布状态的影响,随着SiC含量的增加呈缓慢下降的趋势;而当致密度低于临界值后,致密度成为热导率的决定性因素,使得复合材料的热导率随着致密度的降低快速下降。The AlN-Mo-SiC composite ceramics with relative density of more than 98.5% with AlN,Mo and SiC as the starting materials could be prepared by spark plasma sintering（SPS） at the temperatures of 1700 ℃ and under the pressure of 30 MPa.The phase structure and microstructure of different SiC content samples were observed by X-ray diffraction（XRD） and field-emission scanning electron microscope（FESEM） respectively.The dielectric properties and thermal conductivity were also tested.The experimental results showed that AlN/Mo/SiC composite ceramics with high relative density could be prepared by utilizing spark plasma sintering under a lower temperature than before;however,with the increase of SiC volume fraction,the relative density decreased sharply when the fraction of SiC volume reached 60%.With the addition of SiC,the electrical resistivity of composite ceramics could be controlled more accurately compared with AlN/Mo composite ceramics to avoid percolation.Under 26.5~40.0 GHz,dielectric constant and dielectric loss of composite ceramics increased with the increase of SiC volume fraction.The thermal conductivity of composite ceramics decreased with the increase of SiC volume fraction.When the relative density was higher than a threshold,its thermal conductivity was mainly determined by the volume fraction and distribution of SiC;however,when the relative density was lower than a certain critical value,it became a determining factor of thermal conductivity,which made the thermal conductivity decrease sharply with the decreasing density.

关 键 词：AlN/Mo/SiC复合陶瓷 放电等离子烧结 电阻率 介电性能 热导率 

分 类 号：TF802.67[冶金工程—有色金属冶金]