PVD法制备6.5%Si高硅钢薄板过程Si、Al共渗交互作用机制研究

6.5%Si高硅钢具有磁感高、铁损低等优异软磁性能，是制作低噪音、低铁损铁芯的理想材料。但因B2和DO3有序相析出导致合金硬而脆，难于采用传统轧制工艺制成薄板。项目申请人发明了PVD法在低硅钢薄板双面共沉积富Si层并扩散制备6.5%Si高硅钢薄板的方法。前期研究发现Si渗速低是该技术实用化的技术瓶颈。本项目设计在低硅钢薄板双面PVD法沉积SiAl膜并进行高温真空扩散处理，通过研究膜层成分结构与扩散工艺参数等因素变化对Si、Al渗入低硅钢基体扩散行为的影响规律，弄清低硅钢基体Si、Al共渗交互作用机制和扩散动力学关系，从Al激发基体晶格缺陷如空位浓度、位错密度而降低Si扩散势垒的角度探讨Al助渗Si的可能条件及微观机理。最后通过工艺有效调控制成6.5%Si高硅钢薄板，并研究Al掺量变化与其组织结构及性能的内在联系，确定Al最佳掺比，为PVD法制备6.5%Si高硅钢薄板奠定理论和实践研究基础。

The Fe-6.5 wt.% Si alloy has been regarded as an ideal core material due to its higher permeability, higher saturation magnetization and lower core losses than conventional Fe-3wt.% Si steel sheets especially at high frequencies. However, the high-Si alloys are known to be quite brittle, which brings about difficulty in conventional hot-cold rolling processes. This drawback restricts the application of Fe-6.5 wt.% Si alloy in practice. In the present work, physical vapor deposition (PVD) technique will be applied to deposit SiAl films onto double surfaces of low-Si steel substrates, to investigate effect of the deposition and diffusion variables on Si and Al distribution in the substrates in an attempt to clarify the underlying interaction mechanisms of Si and Al co-penetration into low-Si sheets, and discuss the possibilities of Al atom enhancing Si penetration in the diffusion process from kinetic calculation and the micro-structure analysis such as voids contents and dislocation densities. Finally, by optimizing the parameters and conditions, fabricate Fe-6.5 wt.% Si alloy from a conventional Fe-3 wt.% Si sheet, meanwhile the relationship of Al concentration and the magnetic and mechnical properties of fabricated Fe-6.5 wt.% Si alloy should be investigated to conclude a suitable Al ratio. Based on the better understanding of the the critical technology in the enriching-Si mechanisms, the conclusion is expected to be able to guide the fabrication of Fe-6.5 wt.% Si thin sheets by PVD approach in an industrial scale.