摘要
以硅粉作为反应原料,在N_(2)气氛中通过燃烧合成制备Si_(3)N_(4)粉体。为获得烧结活性好的高α相Si_(3)N_(4)粉体,在燃烧合成过程中需要加入一定比例的稀释剂。分别以粒径为3μm的α-Si_(3)N_(4)、β-Si_(3)N_(4)和BN粉体作为稀释剂,将硅粉、稀释剂、NH_(4)Cl按一定质量比(46∶49∶5)均匀混合,在6 MPa氮气压力下燃烧合成制备Si_(3)N_(4)粉体。利用X射线衍射仪、扫描电子显微镜、X射线能谱对产物相组成、相含量和显微结构进行研究,并分析不同种类稀释剂对燃烧合成Si_(3)N_(4)粉体的影响。结果表明:以3μm的α-Si_(3)N_(4)、β-Si_(3)N_(4)作为稀释剂的燃烧合成过程的最高温度均高于1700℃,制得的产物中,新生成的α-Si_(3)N_(4)均低于40%(质量分数);以3μm的BN作为稀释剂燃烧合成过程的最高温度略高于1500℃,制得的产物中,新生成的α-Si_(3)N_(4)含量高于90%(质量分数)。产物中的α-Si_(3)N_(4)粉体为爪状或菜花状形貌,β-Si_(3)N_(4)粉体为棱柱状形貌,不同相Si_(3)N_(4)粉体粒径分布较为均匀。最终,相比较于以Si_(3)N_(4)粉体作为稀释剂,以BN粉体作为稀释剂可以降低燃烧合成的最高反应温度并有效隔离硅熔体,从而提高Si_(3)N_(4)产物的α相含量。
Si_(3)N_(4)powders were prepared by combustion synthesis in N_(2)with silicon powder as reaction raw material.A certain amount of diluent was added in order to obtain highα-phase Si_(3)N_(4)powders with good sintering activity.The silicon powder,diluents and NH_(4)Cl were uniformly mixed in the certain mass ratio(46∶49∶5)and used to prepare Si_(3)N_(4)powders by combustion synthesis under 6 MPa N_(2)pressure,in which the diluents wereα-Si_(3)N_(4),β-Si_(3)N_(4)and BN powders with the particle size of 3μm.The phase composition and microstructure of the products were studied by X-ray diffractometer,scanning electron microscope and X-ray energy spectrum,and the effect of diluent on Si_(3)N_(4)powders by combustion synthesis was analyzed.The results showed that the highest temperatures of samples withα-Si_(3)N_(4)andβ-Si_(3)N_(4)as diluents were higher than 1700℃,and the contents of newly formedα-Si_(3)N_(4)were less than 40%(mass fraction)in the prepared products.With 3μm BN as diluent,the highest temperature of combustion synthesis was slightly higher than 1500℃,and the content of newly formedα-Si_(3)N_(4)in the prepared product was higher than 90%(mass fraction).α-Si_(3)N_(4)particle in the product was in the shape of claw or cauliflower,andβ-Si_(3)N_(4)particle was in the shape of prismatic.The particle size distribution of Si_(3)N_(4)powders with different phases were more uniform.Finally,compared with Si_(3)N_(4)powder as diluent,BN powder as diluent can reduce the maximum reaction temperature of combustion synthesis and effectively isolate silicon melt,thus increasing theαphase content of Si_(3)N_(4)product.
作者
李飞
崔巍
田兆波
张杰
杜松墨
陈张霖
刘光华
LI Fei;CUI Wei;TIAN Zhaobo;ZHANG Jie;DU Songmo;CHEN Zhanglin;LIU Guanghua(School of Materials Science and Engineering,Tsinghua University,Beijing 100084,China;Foshan(Southern China)Institute for New Materials,Foshan 528000,Guangdong,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第10期36-39,共4页
Materials Reports
基金
中国博士后科学基金(2018M641344,2020T130335)。
关键词
燃烧合成
稀释剂
氮化硅
combustion synthesis
diluent
silicon nitride
