镀锌30CrMnSi锌铁扩散层生长动力学

Growth kinetics of zinc-iron diffusion layer in galvanized zinc 30CrMnSi

采用控制变量法研究了镀锌30Cr Mn Si在不同保温温度和时间条件下的界面演化行为,并结合扫描电子显微镜和电子探针等技术手段,对界面显微组织演化规律与元素扩散行为特征进行分析。结果表明:锌铁扩散层中金属间化合物生成顺序依次为ζ相、δ相、Γ相;当保温温度在300℃以上时,扩散层中金属间化合物生长主要由扩散速率控制,层厚呈抛物线增长;保温温度在300℃以下时,锌扩散速率较低,金属间化合物生长主要由界面反应控制,层厚呈近线性增长,计算获得锌铁反应激活能为162.37 k J/mol。建立镀锌30Cr Mn Si锌铁扩散层的生长动力学模型,通过此模型可对实验温度下锌铁扩散层厚度进行初步计算。

The galvanized zinc 30 Cr Mn Si was annealed at different temperatures for different time,the diffusion kinetics of zinc and the laws of microstructural evolution at different holding temperatures were studied by means of SEM and EPMA. The results show that intermediate phases appear in the order of ζ、δ、Γ phase; when the holding temperature is above 300 ℃,the growth of intermetallic compounds in zinc-iron diffusion layer is controlled by diffusion rate,thickening as a parabolic growth,and when the holding temperature is below 300 ℃,the diffusion rate of zinc is very low,and the growth of intermetallic compounds is determined mainly by interface reaction rate and the thickening shows an approach linear growth behavior. The growth activation energy for the growth of the compound is 162. 37 k J / mol. The growth kinetics model is obtained,by which the thickness of the diffusion layer can be evaluated at experimental temperature.