【作者】 赵满秀；

【导师】 苏旭平；

【作者基本信息】 湘潭大学 ， 材料科学与工程， 2006， 硕士

【摘要】 钢铁腐蚀给国民经济造成巨大的损失，热镀锌作为最基本的防护手段之一，对减少这种损失发挥着重要作用。近年来，热镀锌件在汽车制造、建筑、家用电器等方面得到了越来越广泛的应用。但是，由于在液态锌中的磨蚀，在热镀锌生产线上工作的零件，如锌锅、沉没辊、支承辊、轴承等失效严重，严重阻碍了热镀锌业的进一步发展。针对这一问题，本文对耐锌液腐蚀材料进行了研究。本文首先分析了液锌对钢铁材料的腐蚀机理，在此基础上，通过比较已有的成果和查阅有关相图进行了耐液锌腐蚀材料的选择，最终确定以Fe-Al-B和Fe-Al-Si作为研究对象。本文采用扫描电镜（SEM）观察合金基体和腐蚀界面的显微组织、能谱仪（EDS）分析各相的化学成分；用失重法并结合能谱仪分析腐蚀界面的化学成分以评定合金的耐蚀性；用显微压痕法评定耐蚀性较好合金的力学性能。对Fe-Al-B合金进行实验研究，结果表明：当含Al（wt．％，下同）＜18％时，Fe-B-Al合金的耐液锌腐蚀性主要由B含量所决定，随着Al含量增加，B含量减少，材料的耐液锌腐蚀性变差：当Al＞18％时，主要由Al含量决定，18％＜Al＜27％时，随着Al含量增加，硼含量减少，材料耐蚀性增大；但Al＞27％时随着铝含量增加，耐液锌腐蚀性反而下降；同时，本研究发现，当Al＞24％时，合金中未发现硼化物，合金韧性较好。通过以上研究分析表明：合金Fe-24Al-4.2B和Fe-27Al-2.8B在锌液中既具有良好的耐蚀性，又具有较好的韧性，它们不仅适合于常规热浸镀锌，也适合于高温热浸镀锌，因此在镀锌工业中具有一定的实际应用价值。合金退火后的耐液锌腐蚀性能优于铸态。对Fe-Al-Si合金进行实验研究，结果表明：当Fe-Al-Si合金系的Al（wt．％）为7％-22％、Si（wt．％）为22％-41％时，合金在500℃时主要形成FeSi、（Al，Si）₂Fe₁、（Al，Si）₃Fe₁、（Al，Si）₅Fe₁和（Al，Si，Nd）₂Fe₁等金属间化合物，与锌液不湿润，但合金的脆性较大，并且随着Si含量的增加，合金的脆性增大。当在Fe-Al-Si合金系中加入少量的稀土元素以后，合金的组织更致密，更细小，韧性得到了较大的改善，硬度略有升高。研制出的合金在锌液中具有良好的耐蚀性，同时该研究为进一步开发出韧性较好的耐锌蚀材料提供了理论基础。更多还原

【Abstract】 Steel corrosion causes huge losses to the national economy. Hot-dip galvanizing as one of the most basic protection plays an important role in reducing such losses. In recent years, hot-dip galvanizing devices have been widely used in automobile manufacturing, construction, household appliances. However, due to corrosion in liquid zinc, apparatuses useed in the Hot-dip galvanizing line （such as Zinc pot, Submerged roll, Support roll and Bearing） are often failure in work, which hinder the further development of the hot-dip galvanizing seriously.The mechanism of liquid zinc corrosion of the steel material was investigated in the first part. On this basis, by comparing the available information in literature and phase diagrams, Fe-Al-B and Fe-Al-Si alloys were choosen as candidates for liquid zinc corrosion-resistant materials.By scanning electron microscopy （SEM） attached with energy dispersive X-ray spectroscopy （EDS）, the microstructures and chemical compositions of alloy matrix and corrosion interface were investigated. The corrosion rate was determined by the weight-loss measuring and the mechanical properties of the alloys with good corrosion resistance were also tested by means of micro-pressing mark.The experimental study of Fe-Al-B alloy shows that: when Al content is less than 18 wt.%, liquid zinc corrosion-resistant of Fe-Al-B alloy change with content of B. With the increase of Al content and reducing boron content, liquid zinc corrosion resistant deteriorates. When Al content is more than 18wt.%, Al content plays the key role. When Al content lies in the range of 18wt%～27wt.%, with the increase of Al content and reducing boron content, liquid zinc corrosion-resistant increases. When Al content is more than 27wt.%, with increase of Al content, liquid zinc corrosion-resistant declines instead. When Al content is more than 24wt.%, no Borides was found in the alloys. Meanwhile, the alloys, Fe-24Al-4.2B and Fe-27Al-2.8B, both with the excellent corrosion-resistance to zinc-liquid and good toughness, can be used widely in galvanizing industry. Alloy after annealing is superior to cast alloys in liquid zinc corrosion-resistant.Results of the experimental study of Fe-Al-Si shows that: when Al content is 7%-22%wt.%, Si content is 22%-41% wt.%; the microstructure is mainly composed of FeSi、（Al,Si）₂Fe₁、（Al.,Si）₃Fe₁、（Al,Si）₅Fe₁ and （Al,Si,Nd）₂Fe₁. They have no wetting to liquid zinc, but the alloys are very brittle. With increasing silicon content in the alloy, the brittleness increases. When a small amount of the rare-earth element is added to Fe-Al-Si alloy system, the microstructure of alloy is more compact and small, toughness is greatly improved and hardness is slightly higher. The developed alloy shows good corrosion-resistance in the liquid zinc, and this work provides a theoretical basis for the further development of zinc corrosion-resistant material with better toughness.更多还原