【作者】 尹付成；

【导师】 苏旭平； 张平；

【作者基本信息】 湘潭大学 ， 材料物理与化学， 2004， 博士

【摘要】 锌及锌基合金主要用于热浸镀锌，提高钢制件的耐腐蚀性能。每年超过50％的锌用于该目的，目前国内镀锌业以每年50％的速度增长。镀锌工艺可以分为一般镀锌和连续镀锌两种。尽管镀锌工艺历史悠久，但在理论和技术上仍然存在许多难以解决的难题。在一般镀锌中，含硅钢在镀锌过程中由于硅的反应性，使得镀层质量变差。通过往锌池中加入一定的镍或者提高镀锌温度，可以在一定程度上抑制硅的反应性，但机理不清楚。在连续镀锌过程中，铝是一种重要的添加元素，可以抑制中间相的产生，减少镀层的脆性。但铝含量的高低直接影响镀层质量和镀锌工艺，其含量必须严格控制，企业迫切需要一种精确测定有效铝的系统。锌池中的铝和稀土可以提高镀层的耐蚀性。熔锌具有强烈的腐蚀性，目前用于镀锌的耐磨耐蚀材料的性能不能满足生产需要。 锌池中合金元素对镀层质量起到关键作用，其成分一般都特别复杂。锌池热化学性质的研究对于控制镀锌质量、优化工艺过程和开发新型镀锌合金具有重要的作用。目前对锌池合金体系的热化学性质及耐磨耐蚀合金的了解甚少。本文选取锌池体系中最重要的Si、Al、Ni、RE等元素，围绕Zn-Fe-Si、Zn-Fe-Al、Zn-Fe-Si-Ni、Fe-Mo-Cr-Ni、RE-Al、RE-Ag等体系在热力学分析、相图测试、工艺控制和合金设计等方面展开研究。以期解决镀锌过程中的几个基础和应用问题。 由于Fe-Zn-Si三元系在镀锌工业中的重要性，本工作采用Thermo-Calc软件，利用CALPHAD技术，对该体系进行了热力学计算，根据晶体结构建立了δ，Γ₁，Γ等相的亚点阵模型：（Fe，Zn，Si）₁₀Zn₁₆、（Fe，Zn，Si）₁₄Zn₁₂和（Fe，Zn，Si）₄ Fe₂Zn₂₀，获得了该体系中每个相的热力学模型参数。利用这些参数，可以对热力学数据和相关系进行合理、可靠、自洽地描述及获得准确的相图数据。这些工作对理解硅的反应性有重要的意义。Al、RE是镀锌合金中的重要添加元素，而Ag-Zn是一种重要的焊接材料，作为基础研究，对La-Al，Ce-Al，Pr-Al，Ag-Pr，Ag-Ce等合金体系进行热力学优化和评估，为建立高元体系的热力学分析数据库打下基础。 含硅钢的镀锌涉及到Zn-Fe-Si-Ni四元合金体系。相图和热力学描述有利于对其机理的理解。利用金相显微镜，SEM-EDS和X-射线衍射方法研究了不同合金的显微组织和相组成，获得Zn-Fe-Si-Ni四元系富锌角560℃等温截面。实验发现，在富锌角FeSi基本上与所有相存在平衡，包括T、δ、γ-Ni、NiSi₂和液相。更多还原

【Abstract】 Zinc and Zinc-based alloys are used mainly in hot-dipping galvanizing to improving the corrosion-resistance of steel. More than half of zinc is used for this purpose. In recent years, the Chinese galvanizing industry has expanded at an astonishing speed of 50% annual rats. There are two kinds of galvanizing processing, by batch or continuous galvanizing. Batch galvanizing has a long history, but there are still many technnical challenges for Si-containing steel resulting from Si Reactivity. The adding of Ni into the zinc bath or increasing of the galvanizing temperature can inhibit the reactivity partially. But the mechanism is not well understood. Al is the most important addation element in continuous galvanizing. It can inhibit the formation of Fe-Zn compounds and reduce the brittleness of coating. The content of Al in bath must be controlled precisely for its effects on the quality of coating and galvanizing processes. This results in the need of the measuring system of effective aluminium. Al and Rare Earth in bath can improve the corrosion resistance of coating. Zinc bath can react with most of alloys. The materials used in galvanizing equipment can’t fulfil the need of galvanizing industries.The alloying elements in bath play a key role in controlling of coating quality. The composition of the bath is very complex in general. The researches in thermochemistry properties of alloy systems in zinc bath and the wear- and corrosion- resistent alloy is not systematic, which are most important for optimizing the processing and controlling the coating quality and developing new zinc alloy used in galvanizing, In present work, the thermodynamic properties and phase relations of zinc alloys systems containing Si, Al, Ni, RE were investigated. The results are used in processes controlling and alloy design.The thermodynamic calculation of Fe-Zn-Si system was conducted by CALPHAD technology through Thermo-calc software, which is very important in galvanizing. The sublattice models for δ, Γ₁, Γ phases are proposed as （Fe,Zn,Si）₁₀Zn₁₆、 （Fe, Zn,Si）₁₄Zn₁₂ and （Fe, Zn, Si）₄ Fe₂Zn₂₀, based on the crystal structures. The consistent set of thermodynamic parameters describing thermodynamic properties of phases is obtained. The result can be used in understanding Si Reactivity. Rare Earth and Al are important adding elements, and Ag-Zn alloy is an important welding material. As a kind of fundamental research, the thermodynamic更多还原