Effects of MgO addition on the microwave dielectric properties of high thermal-conductive silicon nitride ceramics sintered with ytterbia as sintering additives |
| |
Authors: | Hiroyuki Miyazaki Kiyoshi Hirao Yu-ichi Yoshizawa |
| |
Affiliation: | 1. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050, China;2. College of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China |
| |
Abstract: | 1 mol% of MgO was added together with 7 mol% of Yb2O3 as sintering additives to silicon nitride powder to fabricate advanced silicon nitride ceramics with both high thermal conductivity and low dielectric loss at 2 GHz. The mixed powder was CIPed at a pressure of 120 MPa and was gas-pressure sintered at 1900 °C to >98% of theoretical density. The sintered Si3N4 sample exhibited a high thermal conductivity of ~100 W m?1 K?1 and a loss tangent (tan δ) of ~4 × 10?4, concurrently. The tan δ was further reduced by half after the heat treatment at 1300 °C for 24 h. The improvement in tan δ due to the annealing was explained from the point of crystallization of the intergranular glassy phase. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|