钡铁氧体前驱体高能球磨过程的红外拟合光谱分析

高能球磨法是材料制备过程中常用的方法，通过物料在高速运转的过程中进行磨合而产生晶体空位缺陷，实现元素的掺杂，进而发生化学吸附或化学反应，合成产生新的物相，对于后续合成材料的性能有很大影响。钡铁氧体具有良好的磁性能，被用于功能材料制备的诸多领域。采用高能球磨法制备钡铁氧体前驱体，利用XRD，SEM和FTIR检测方法考察不同高能球磨时间下钡铁氧体前驱体物相、微观形貌及官能团的变化规律，并通过红外二阶导数光谱、拟合平滑光谱计算法，定量分析高能球磨过程中物相的变化规律。XRD及SEM检测结果表明，随球磨时间增加，钡铁氧体前驱体各物相的衍射峰宽度变宽，粉末细化，晶格逐渐发生畸变，产生晶体空位缺陷，从而使Ba溶入Fe₂O₃晶格中生成Ba_xFe_2-xO₃的固溶体，且产生吸附“团聚”现象；当球磨时间大于40 h时，发生“纳米尺寸效应”，生成有磁性的Fe₃O₄及Ba_xFe_3-xO₄固溶体。红外光谱分析结果显示，随着球磨时间的增加，BaCO₃和α-Fe₂O₃的特征峰均存在峰强减小、峰位发生明显移动的规律，表明随着球磨时间增加，BaCO₃和α-Fe₂O₃颗粒粒度变小，且发生化学吸附。通过红外光谱的平滑拟合光谱和二阶导数光谱计算可知，随球磨时间的增加，各吸收峰面积均明显减小。相对于球磨0 h，在球磨10，20和40 h后，波数473 cm-1的Fe—O键振动吸收峰的峰面积分别减少48.84%，65.97%和93.54%；而在波数540 cm-1处的Fe—O键吸收峰的峰面积则分别减少37.11%，51.76%和82.85%；同理，在波数856 cm-1处的O—C—O键的面内弯曲振动吸收峰的峰面积分别减少30.62%，44.71%和67.10%；在波数1 446 cm-1处的C—O键不对称伸缩振动峰的峰面积则分别减少0.03%，27.63%和57.90%。从定量分析的角度考察了钡铁氧体前驱体高能球磨过程中物相的变化规律并精准确定反应产物含量变化的百分比，对于后续材料的合成与性能随钡铁氧体前驱体物相不同而发生变化的研究有重要的指导意义。

Infrared Spectral Fitting Analysis of Barium Ferrite Precursor in High Energy Ball Milling Process

High energy ball milling method was a common method in the process of material preparation, which produced crystal vacancy defects through the material running with high speed to achieve the doping of elements, so the chemical adsorption or chemical reaction has occurred. New phase formed, and it has a great impact on the performance of subsequent synthetic materials. Barium ferrite has been used in many functional materials because of its good magnetic properties. In the paper, barium ferrite precursor was prepared by the high energy ball mill method. Using XRD, SEM and FTIR methods, the changes in phase, microstructure and functional groups of barium ferrite precursor with different high energy ball milling times were investigated. By the second derivative infrared spectroscopy and smooth fitting calculation method, the phase changes were quantitatively analyzed in the process of high-energy ball mill of materiel. XRD and SEM results show that with the increase of ball milling time, the diffraction peak width of each phase of the barium ferrite precursor becomes wider, the powder is refined, the crystal lattice is gradually distorted, and crystal vacancy defects are produced, so that Ba dissolves into the Fe₂O₃ lattice to produce the solid solution of Ba_xFe_2-xO₃, and the adsorption “agglomeration” is produced phenomenon. When the milling time was longer than 40 h, the “nano-size effect” occurred, and magnetic Fe₃O₄ and Ba_xFe_3-xO₄ solid solutions were generated. The results of infrared spectrum analysis showed that the characteristic peaks of BaCO₃ and α-Fe₂O₃ decreased and shifted significantly with the increase of ball milling time, indicating that the particle size of decreased and chemical reactions occurred with the increase of ball milling time. The smooth fitting spectrum and the second derivative spectrum of the infrared spectrum showed that the area of each absorption peak decreased obviously with the increase of the milling time. Compared with that of ball milling under 0h, after ball milling for 10, 20 and 40 h, the vibration absorption peak area of Fe—O bond at 473 cm-1 decreased by 48.84%, 65.97% and 93.54%, respectively, and at 540 cm-1, the absorption peak area of the Fe—O bond decreased by 37.11%, 51.76% and 82.85%, respectively. Similarly, the absorption peak area of in-plane bending vibration of the O—C—O bond at 856 cm-1 was 30.62%, 44.71% and 67.10%, respectively, and the peak area of C—O bond asymmetric stretching vibration at the wavenumber of 1 446 cm-1 decreased by 0.03%, 27.63% and 57.90%, respectively, compared with that of ball milling at 0 h. In this way, the phase changes of barium ferrite precursors during high energy ball milling were investigated, and the percentage changes of reaction product content were accurately determined based on quantitative analysis, which has important guiding significance for the research on the changes in subsequent materials synthesis and properties with the phase changes of barium ferrite precursor.