基于铁硅合金微观结构的硅扩散行为研究
发布时间：2018-08-31 10:33
【摘要】：硅钢作为变压器铁芯不可或缺的材料,广泛应用于电力设备中,其拥有良好的软磁性能,特别地,当硅含量达到6.5wt%时,磁致伸缩几乎为零,低铁损、高矫顽力,几乎是完美的电工钢材料。CVD法是目前唯一实现工业化生产高硅钢的方法。本文基于CVD法制备高硅钢的原理,提出了晶界扩散在硅综合扩散中的重要作用,构建了一种硅体扩散和晶界扩散相结合的数值模型用于预测渗硅过程中硅含量的分布,并且分析了基材的前处理对渗硅效率的影响,对实现高硅钢的工业化生产有着重要的参考价值。基于CVD法要求搭建了实验室制备高硅钢的设备,测定了管式炉的低温和高温恒温区,确定了反应气SiCl4浓度与水浴锅温度的数值关系,确定其与载气N2流量无关。介绍了实验的操作以及工艺参数的控制方式,在真空管式炉内进行CVD渗硅实验,利用扫描电子显微镜(SEM)和能谱仪(EDS)沿渗硅深度方向定量测量了样品晶界附近和晶粒内部的硅含量,发现晶界附近的硅浓度以及渗透深度明显高于晶内,说明晶界起到了快速扩散通道的作用。利用SEM和金相分析软件得到了晶界宽度及晶粒大小等微观参数并将其应用于几何建模,基于Voronoi图原理,在Matlab和ABAQUS软件环境下建立了硅扩散模型。采用Boltzmann-Matano求取体扩散系数,并将其代入模型计算;对比实验和模拟的平均硅含量值得到了 1100℃和1200℃下的晶界扩散系数,其比体扩散系数高103～104倍,经过验证,模型很好的预测了硅含量的分布。对基材进行热处理,探究了温度、保温时间和加热方式对晶粒大小的影响;通过对比基材退火前后渗硅的差异发现,冷轧板比热处理后的基材渗硅效率高;建立了基材平均硅含量和渗硅时间的关系式,对构建连续性渗硅装置有着重要的指导意义。
[Abstract]:As an indispensable material for transformer core, silicon steel is widely used in power equipment. It has good soft magnetic properties. In particular, when silicon content reaches 6.5 wt%, magnetostriction is almost zero, low iron loss and high coercivity. Almost perfect electrical steel material. CVD method is the only way to produce high silicon steel. Based on the principle of preparing high silicon steel by CVD method, the important role of grain boundary diffusion in silicon comprehensive diffusion is put forward in this paper. A numerical model combining silicon diffusion and grain boundary diffusion is constructed to predict the distribution of silicon content in siliconizing process. The effect of pretreatment on the efficiency of siliconizing is analyzed, which has important reference value for realizing the industrialized production of high silicon steel. Based on the requirement of CVD method, a laboratory equipment for preparing high silicon steel was built, and the low and high temperature constant temperature regions of the tube furnace were measured. The numerical relationship between the reaction gas SiCl4 concentration and the temperature of the water bath pot was determined, and it was determined that it was independent of the N 2 flow rate of the carrier gas. The operation of the experiment and the control mode of the process parameters are introduced. The CVD siliconizing experiment is carried out in the vacuum tube furnace. The silicon content near and inside the grain boundary was measured quantitatively by scanning electron microscope (SEM) and energy spectrometer (EDS) along the direction of the depth of siliconizing. It was found that the concentration and penetration depth of silicon near the grain boundary was obviously higher than that in the crystal. The results show that the grain boundary acts as a fast diffusion channel. The microcosmic parameters such as grain boundary width and grain size were obtained by SEM and metallographic analysis software, and applied to geometric modeling. Based on the principle of Voronoi diagram, the silicon diffusion model was established under the environment of Matlab and ABAQUS software. The volume diffusion coefficient was calculated by Boltzmann-Matano, and calculated by the model. The average silicon content in the comparison experiment and simulation is worth the grain boundary diffusion coefficient at 1100 鈩，
本文编号：2214721
[Abstract]:As an indispensable material for transformer core, silicon steel is widely used in power equipment. It has good soft magnetic properties. In particular, when silicon content reaches 6.5 wt%, magnetostriction is almost zero, low iron loss and high coercivity. Almost perfect electrical steel material. CVD method is the only way to produce high silicon steel. Based on the principle of preparing high silicon steel by CVD method, the important role of grain boundary diffusion in silicon comprehensive diffusion is put forward in this paper. A numerical model combining silicon diffusion and grain boundary diffusion is constructed to predict the distribution of silicon content in siliconizing process. The effect of pretreatment on the efficiency of siliconizing is analyzed, which has important reference value for realizing the industrialized production of high silicon steel. Based on the requirement of CVD method, a laboratory equipment for preparing high silicon steel was built, and the low and high temperature constant temperature regions of the tube furnace were measured. The numerical relationship between the reaction gas SiCl4 concentration and the temperature of the water bath pot was determined, and it was determined that it was independent of the N 2 flow rate of the carrier gas. The operation of the experiment and the control mode of the process parameters are introduced. The CVD siliconizing experiment is carried out in the vacuum tube furnace. The silicon content near and inside the grain boundary was measured quantitatively by scanning electron microscope (SEM) and energy spectrometer (EDS) along the direction of the depth of siliconizing. It was found that the concentration and penetration depth of silicon near the grain boundary was obviously higher than that in the crystal. The results show that the grain boundary acts as a fast diffusion channel. The microcosmic parameters such as grain boundary width and grain size were obtained by SEM and metallographic analysis software, and applied to geometric modeling. Based on the principle of Voronoi diagram, the silicon diffusion model was established under the environment of Matlab and ABAQUS software. The volume diffusion coefficient was calculated by Boltzmann-Matano, and calculated by the model. The average silicon content in the comparison experiment and simulation is worth the grain boundary diffusion coefficient at 1100 鈩，
本文编号：2214721
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