粉末渗锌工艺中锌扩散的数值模拟  

Diffusion Numerical Simulation of Zinc in Sherardizing

作　　者：高海云 李小波[1] 冯文营 彭淀 

机构地区：[1]湘潭大学,湖南湘潭411105

出　　处：《表面技术》2018年第1期135-141,共7页Surface Technology

基　　金：国家自然科学基金(51071181)~~

摘　　要：目的采用数值模拟法预测粉末渗锌的扩散过程。方法通过分析粉末渗锌的机理及渗锌层的形成过程,基于Fick第二定律,采用有限差分法建立了以锌为主扩散元素的渗锌模型。采用该模型模拟计算一定温度范围、一定时间内的渗锌层厚度和Zn含量随时间和温度的变化,并与相同条件下的实验测量值进行对比,验证模型的可靠性。实验制备了在360、375、390℃下分别保温4、6、8 h的渗锌样品,通过扫描电镜-能谱仪以及Smile View软件测定了样品中合金层的各相厚度和Zn含量,并与数值模拟计算结果进行对照。结果实验测定的各相含量变化与计算结果吻合较好,合金层各相厚度及总厚度与计算结果接近。该模型能很好地反映渗锌层Zn含量及厚度随时间和温度的变化规律,可以计算模拟一定温度范围、一定时间内的渗锌层厚度及Zn含量变化。结论该模型能有效预测粉末渗锌的扩散过程,可以用来指导渗锌工艺。The work aims to predict diffusion process of sherardizing in the method of numerical simulation. Based on analysis of sherardizing mechanism and formation process of Fe-Zn coatings as well as the Fick＇s second law, the sherardizing model with zinc as the main diffusion element was established in finite difference method. Variation of thickness and content of Zinc layer as a function of time and temperature in a certain temperature range and time was calculated and compared with the experimental measurements in the same conditions to validate reliability of this model. Firstly, the sherardizing samples were incubated at 360, 375, 390 ~C for 4, 6, 8 hours, respectively. Secondly, phase thickness and Zn content of alloy layer in the sam- ples were measured with scanning electron microscopy/energy-dispersive spectrometer and SmileView software, the measure- ments were compared with the results of numerical simulation. Content variation of various phases measured by the experiments coincided with calculation result. The phase thickness and total thickness of the alloy layer were close to calculation results. The model could favorably reflect the variation of Zinc layer content and thickness as a function of time and temperature, it could also be used to calculate and simulate variation of Zinc layer thickness and content in certain temperature range and certain time.Therefore, this model is of general validity to predict the zinc diffusion during sherardizing and can be used to guide the sherar- dizing process.

关 键 词：粉末渗锌 数值模拟 有限差分 扩散 模型 FICK第二定律 

分 类 号：TG174.445[金属学及工艺—金属表面处理]