LaF_3-MgO助烧剂配比对Si_3N_4陶瓷烧结及性能的影响  

Sintering and Properties of Si_3N_4 with LaF-3/MgO Additives

作　　者：钟楠[1] 宁晓山[1] 白冰[1] 杜路[1] 

机构地区：[1]清华大学新型陶瓷与精细工艺国家重点实验室,北京100084

出　　处：《稀有金属材料与工程》2011年第S1期506-509,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50872062)

摘　　要：采用放电等离子烧结(SPS)后高温热处理的方法,制备烧结助剂总量为8%(质量分数),LaF3/MgO配比不同的Si3N4陶瓷,研究助烧剂配比对Si3N4陶瓷烧结及热导率、抗弯强度等性能的影响。结果发现,添加LaF3后SPS初期烧结速率明显减小,烧结温度区间变宽,当LaF3/MgO配比超过4:4后烧结密度急剧下降。烧结后陶瓷中形成La-Si-O化合物。热导率随LaF3/MgO比增加先升后降;而抗弯强度初期随LaF3/MgO比变化不大,但当比值超过1后,陶瓷中出现异常长大晶粒,抗弯强度下降。控制LaF3/MgO配比为3:5可以获得热导率为80W/m·K,抗弯强度超过1000MPa的高热导率高强度Si3N4陶瓷。Spark plasma sintering (SPS) and following heat treatment were adopted to fabricate Si3N4 ceramics with 8wt% LaF3-MgO additives. LaF3/MgO ratio changes from 0:8 to 7:1. The influence of the LaF3/MgO ratio on the sintering, thermal conductivity and mechanical properties of samples were studied. The result shows that LaF3 will decrease the speed of sintering. The relative density of the samples significantly decreases when LaF3/MgO ratio is larger than 4:4. La-Si-O compound can be found in the samples with both LaF3 and MgO additives. The thermal conductivity increases and then decreases as the addition of LaF3 increasing. Abnormal elongated grains can be found when LaF3/MgO ratio is beyond 4:4, and thus decrease the bending strength. The thermal conductivity and bending strength can reach 80 W/m?K and 1000 MPa, respectively, when LaF3/MgO ratio is 3:5.

关 键 词：SI3N4 LAF3 热导率 抗弯强度 

分 类 号：TQ174.651[化学工程—陶瓷工业]