XI Wei, ZHOU Yangyang, LIU Pengfei, HAN Zhao
(School of Metallurgical Engineering, Anhui University of Technology, Maanshan 243000, China)
Abstract：Silicon nitride (Si3N4) powder is prone to oxidation, and high oxygen content of surface silicon oxide layer have adverse effects on the mechanical and thermal conductivity of Si3N4 ceramics. In the process of refining Si3N4 powder by ball milling, deionized water, anhydrous ethanol and 20% sodium hydroxide (NaOH) solution were selected as ball milling media, respectively. X-ray diffraction analyzer, laser particle size analyzer, field emission scanning electron microscope, high resolution transmission electron microscope, oxygen nitrogen analyzer, Fourier transform infrared spectrometer and X-ray photoelectron spectrometer were used to analyze the phase composition, particle size distribution, morphology, oxygen content of surface silicon oxide layer, chemical group and chemical bond type and concentration of Si3N4 nano powder. The mechanism of preparing Si3N4 powder with low oxygen content of surface silicon oxide layer by alkaline ball milling was explored. The results show that when NaOH solution is used as the ball milling medium, Si3N4 powder first reacts with water to form a surface silicon oxide layer,and then NaOH reacts with the surface silicon oxide layer. The ball milling process accelerates the dissolution and peeling of the amorphous silicon oxide layer on the surface of Si3N4 powder, reduces oxygen content of surface silicon oxide layer and particle size, and achieves the refinement of Si3N4 powder.The mass fraction of oxygen in Si3N4 powder only increase from 1.00% to 1.25%, but the particle size decrease from 3.50 μm to 0.71 μm. The morphology changed from long strip to good dispersive spherical particles. The O—Si—O bond content of ball milled Si3N4 nano powder decreases from 15.06% to 11.24%. Compared with deionized water and anhydrous ethanol, NaOH solution is the optimal milling medium.
Keywords：ball milling medium; silicon nitride power; morphology; surface silicon oxide layer; oxygen content
Get Citation：XI W, ZHOU Y Y, LIU P F, et al. Effect of ball milling medium on morphology and surface silicon oxide layer of silicon nitride powder[J]. China Powder Science and Technology, 2023, 29(6): 82-90.
DOI：10.13732/j.issn.1008-5548.2023.06.008
Received：2023-06-25,Revised：2023-09-12,Online：2023-10-09 09:25。
Funding Project：国家自然科学基金项目,编号:52072381。
First Author：郗威(1998—),男,硕士研究生,研究方向为氨解法制备氮化硅粉体。E-mail: 1478913946@qq.com。
Corresponding Author：韩召(1977—),男,副教授,博士,硕士生导师,研究方向为氮化硅粉体制备及应用技术。E-mail: authan@163.com。
CLC No：TQ170; TB44
Type Code：A
Serial No：1008-5548(2023)06-0082-09
