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Synthesis mechanism of amorphous Si2BC3N powders: Structural evolution of 2Si‐BN‐3C mixtures during mechanical alloying
Journal of the American Ceramic Society ( IF 3.5 ) Pub Date : 2020-04-18 , DOI: 10.1111/jace.17168
Bin Liang 1 , Xingqi Liao 2 , Qishuai Zhu 2 , Zhihua Yang 2, 3 , Dechang Jia 2, 3 , Yu Zhou 2, 3
Affiliation  

A detailed knowledge of structural evolution during mechanical alloying (MA) is of interest and critical for understanding of synthesis mechanism, optimization of milling process, and control of milling products. The structural evolution of the 2Si‐BN‐3C mixture with a molar ratio of Si:BN:C = 2:1:3 during MA was studied by investigating the changes of phases, morphologies, elemental distributions, microstructures, and chemical bond states using XRD, SEM‐EDS, TEM, XPS, and Raman. With the increases in milling time, the particle sizes of the milled 2Si‐BN‐3C powders first decrease to submicrometers (~1 hour), slightly increase afterward (~3 hours), and eventually decrease to nanoscales gradually reaching equilibrium (≥10 hours). Depending on the intrinsic crystal structures of themselves, h ‐BN and graphite are almost amorphized after milling of 10 hours, while amorphization of c ‐Si takes at least 20 hours. The same milling parameters can provide amorphous Si2BC3N powders, but incompletely amorphous (partially crystalline) SiC powders, which is mainly due to the dilution effect of B and N atoms on the atomic concentration of Si and C hindering the microdiffusion and subsequent mechanochemical reaction of Si and C. Crystallite refinement–induced amorphization is the major synthesis mechanism of amorphous Si2BC3N powders. This work would offer more insight into the MA synthesis of multiple component materials, especially Si‐based brittle systems.

中文翻译:

非晶态Si2BC3N粉末的合成机理:机械合金化过程中2Si-BN-3C混合物的结构演变

机械合金化(MA)过程中结构演变的详细知识对于理解合成机理,优化铣削工艺和控制铣削产品至关重要,并且至关重要。通过研究相的变化,形态,元素分布,微观结构和化学键态的变化,研究了MA期间Si:BN:C = 2:1:3摩尔比为2:Si-BN-3C混合物的结构演变。 XRD,SEM-EDS,TEM,XPS和拉曼 随着研磨时间的增加,研磨后的2Si-BN-3C粉末的粒径首先减小至亚微米(〜1小时),其后略微增加(〜3小时),最终减小至纳米级,逐渐达到平衡(≥10小时)。 )。根据自身的固有晶体结构,h研磨10小时后,BN和石墨几乎非晶化,而c- Si的非晶化至少需要20小时。相同的研磨参数可以提供无定形的Si 2 BC 3 N粉末,但不完全的无定形(部分结晶)SiC粉末,这主要是由于B和N原子对Si和C原子浓度的稀释作用而阻碍了微扩散和随后的扩散。 Si和C的机械化学反应。微晶细化诱导的非晶化是非晶Si 2 BC 3 N粉末的主要合成机理。这项工作将为多组分材料的MA合成,尤其是基于Si的脆性系统的MA合成提供更多的见识。
更新日期:2020-06-27
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