熔盐辅助合成Dy3Si2C2包裹SiC粉体及其陶瓷的烧结行为  

Molten Salt Assisted Synthesis of Dy3Si2C2 Coated SiC Powders and Sintering Behavior of SiC Ceramics

作　　者：万朋 李勉 黄庆 WAN Peng;LI Mian;HUANG Qing(Engineering Laboratory of Advanced Energy Materials,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China;State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]中国科学院宁波材料技术与工程研究所先进能源材料工程实验室(筹),宁波315201 [2]西安交通大学金属材料强度国家重点实验室,西安710049

出　　处：《无机材料学报》2021年第1期49-54,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金(21671195,51902320)。

摘　　要：碳化硅陶瓷因自身优良的物理化学性能而具有广泛的应用前景。碳化硅的化学键结合特性决定了其难以烧结成型,因此如何制备高质量碳化硅陶瓷是领域内的难点之一。本研究以三元稀土碳化物Dy3Si2C2作为新型SiC陶瓷的烧结助剂,依据Dy-Si-C体系的高温相转变原位促进碳化硅的烧结致密化。采用放电等离子烧结技术,利用金属Dy与SiC反应生成Dy3Si2C2,对Dy3Si2C2包裹的SiC粉体进行烧结。在1800℃、45 MPa的烧结条件下,得到了致密度为99%、热导率为162.8 W·m^–1·K^–1的高纯度碳化硅陶瓷。进一步的研究表明,高温下Dy3Si2C2与SiC发生共晶反应,在晶界处产生的液相促进了SiC陶瓷的致密化,表明稀土层状碳化物Re3Si2C2(Re=La,Ce…)有助于SiC的烧结致密。Silicon carbide is widely used because of its excellent physical and chemical properties.The chemical bonding characteristics of SiC make it difficult to be sintered.Therefore,preparation of high-quality SiC ceramics is one of the challenges in SiC research field.In this study,the ternary rare-earth carbide Dy3Si2C2 was proposed as a new sintering additive for SiC ceramics,through the phase transition of Dy-Si-C system at high temperatures to promote the densification of SiC.The Dy3Si2C2 coated SiC powders were synthesized via an in-situ reaction between metal Dy and SiC in high temperature molten salts.The Dy3Si2C2 coated SiC powder was sintered by spark plasma sintering(SPS),at 1800℃,45 MPa.As the result,high-purity SiC ceramic with the density of 99%and thermal conductivity of 162.8 W·m^–1·K^–1 was obtained to form the SiC-Dy3Si2C2 raw material with n(Dy):n(SiC)=1:4.Further study shows that Dy3Si2C2 and SiC undergo a eutectic reaction at high temperatures,which generates liquid phase at the grain boundaries and promotes the densification of SiC ceramics.This study shows that the ternary rare-earth carbides Re3Si2C2(Re=La,Ce…)has great potential to be used as the sintering additive for SiC.

关 键 词：SIC Dy3Si2C2 放电等离子烧结 熔盐 

分 类 号：TQ174[化学工程—陶瓷工业]