摘要
高热导率氮化硅陶瓷作为基板材料有着广泛的应用前景。如何在尽可能保持氮化硅陶瓷机械性能的前提下,提高其热导率是其实际应用的关键,而选择适当的烧结助剂是提高热导率的一个重要途径。本文研究了稀土氧化物种类及CaO、MgO烧结助剂对氮化硅陶瓷的热导率及电学和机械性能的影响,分别采用Y_2O_3-MgO,Y_2O_3-CaO,CeO_2-MgO,CeO_2-CaO,La_2O_3-MgO和La_2O_3-CaO 6种烧结助剂,采用放电等离子烧结后热处理的工艺制备氮化硅陶瓷。研究结果表明:氮化硅陶瓷的热导率随着烧结助剂稀土元素阳离子半径的增大有减小的趋势;与添加MgO助烧结相比,添加CaO助烧结不利于氮化硅柱状晶的生长,热导率及强度普遍较低,但硬度较高。采用Y_2O_3-MgO助烧剂和适当的烧结工艺,可以得到热导率高于80W/m·K、抗弯强度大于1000 MPa、体电阻率大于1×10^(13)Ω·m、介电常数小于10、介电损耗小于3×10^(-3)的氮化硅陶瓷。
Silicon nitride ceramics of high thermal conductivity is a promising candidate for application as ceramic IC substrates. The thermal conductivity of Si3N4 can be changed greatly by the use of different sintering additives. In this work, different systems of additives were used to sinter the silicon nitride ceramics, including Y2P3-MgO, Y2P3-CaO, CeO2-MgO, CeO2-CaO, La2P3-MgO and La2P3-CaO, and their effects on the thermal conductivity and the mechanical and electrical properties of the sintered Si3N4 ceramics were studied. The ceramics were sintered by the spark plasma sintering （SPS） method at 1500 ℃ for 5 min which was then heat treated at 1900 ℃ for 3 h under N2 atmosphere. Results showed that the conductivities of the ceramics sintered from the rare-earth additives tended to decrease with the increase of the cation radius in the rare-earth oxides. Different from the use of MgO, the additives of CaO did not generate the desired rod-like grains of silicon nitride which thus led to a lower thermal conductivity and a lower strength of the ceramics, although it gave a higher ceramic hardness. In contrast, the Y2O3-MgO additive system, under the optimized sintering conditions, provided a higher thermal conductivity of 80 W//m·K, with the bend strength larger than 1000 MPa. Meanwhile, the bulk resistivity was higher than 10^13Ωm, the dielectric constant was lower than 10 and the dielectric dissipation fraction below 3× 10^-3.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2008年第A01期693-696,共4页
Rare Metal Materials and Engineering
基金
国家自然科学基金委员会"高热导率高强度氮化硅陶瓷研究"资助(50472004)
关键词
氮化硅
稀土氧化物
热导率
抗弯强度
电阻率
silicon nitride
rare-earth additives
thermal conductivity
bending strength
resistivity
