摘要
以硅粉和酚醛树脂为原料,硝酸镍为催化剂前驱体,采用微波加热催化反应法,在流通氩气气氛中1150℃/0.5 h反应后合成了β-SiC粉体。研究了反应温度、催化剂用量和保温时间等对合成β-SiC的影响。采用XRD、SEM和TEM对产物的物相组成及显微结构进行了表征。结果表明:微波加热条件下,无催化剂存在时,β-SiC的完全合成温度为1250℃;而添加1.0wt%的Ni作催化剂时,1150℃/0.5 h反应后即可合成纯相的β-SiC。所合成的试样中都存在着颗粒状和晶须状两种SiC,加入催化剂后会使试样中β-SiC晶须的长径比变大。密度泛函理论(DFT)计算结果表明,Ni-Si合金纳米颗粒的形成使Si原子之间的键长拉长,弱化了Si原子之间的结合强度,进而促进了Si粉在低温下的碳化反应。
β-SiC powders were synthesized by a microwave heating method at 1150 ℃ for 30 min under Ar atomosphere using silicon powders and phenolic resin as raw materials, and nickel nitrate as catalyst precursor. The effects of temperature, catalyst content and holding time on the formation of SiC were investigated. XRD, SEM and TEM were used to characterize the phase and microstructure of the prepared samples. It indicated that β-SiC can be synthesized at 1150 for 0.5 h by using ℃1.0wt% Ni as catalysts. In contrast, for the sample prepared without Ni catalysts, corresponding preparation temperature of β-SiC was as high as 1250℃. Both β-SiC whiskers and particles were formed in the samples prepared with or without catalysts, and the length of formed β-SiC whiskers in the samples prepared with Ni catalysts were larger than those without catalyst. Density functional theory（DFT） calculation shows that the formation of Ni-Si alloy can elongate the length of Si–Si chemical bond, weaken its bond strength, and finally accelerate the carbonization reaction of Si powder at a relative low temperature.
作者
王军凯
张远卓
李俊怡
张海军
李发亮
韩磊
宋述鹏
WANG Jun-Kai ZHANG Yuan-Zhuo LI Jun-Yi ZHANG Hai-Jun LI Fa-Liang HAN Lei SONG Shu-Peng(The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China)
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2017年第7期725-730,共6页
Journal of Inorganic Materials
基金
国家自然科学基金(51472184
51472185)
湖北省教育厅高等学校优秀中青年科技创新团队计划(T201602)~~
关键词
Β-SIC
微波加热
催化反应
密度泛函理论
β-SiC
microwave heating
catalytic-reaction
density functional theory
