冷轧薄钢板/无锡钢板表面覆膜机理与关键控制技术研究

Laminated steel with high efficiency, low energy consumption, green environmental protection and excellent corrosion resistance is widely used in the packaging materials field of DRD cans, DI cans, stamping and easy cupping. However, the low recognition of binding mechanism between the surface organic membrane and the substrate and its key control technology are the key problems to restrict the development and application of laminated steel.. Based on the intrinsic physical properties evolution for cold rolled steel sheet and controlling organization structure, and compositions ration of hydrous oxide on tin free steel, the impact mechanism of surface energy for tin free steel are studied using the static water contact angle / surface tension method analysis. According to the surface structural change of chromium hydrous oxide for heating zone as well as surface roughness degree Ra, Rz, Rsm and Rpc and other physical properties change of different cold-rolled steel sheet, surface internal stress evolution of PET membrane and its influencing factors are researched by means of modern research methods combined with TEM, ATM, XPS, Raman spectroscopy and drilling methods. After the analysis of attenuation of the surface stress of the PET film and the surface chromium chemical bond evolution in the typical environment, the influence on aging mechanism of PET film is to be revealed. The above research will provide theoretical support for understanding the mechanism of film mulching and promoting the development of laminated steel.

覆膜铁具有高效、低能耗、绿色环保和优异的耐腐蚀性能，在DRD冲压罐、DI冲拔罐、易开盖等包装材料领域有着广泛应用。但对冷轧薄钢板/无锡钢板表面覆膜机理与关键控制技术认知度低成为限制覆膜铁发展的瓶颈问题。. 本项目通过冷轧薄钢板表面的本征物理特性演变和无锡钢表面铬水合氧化物组织结构、成分比例调控，采用静滴接触角/表面张力法分析无锡钢板表面能的影响机制。结合TEM、ATM、XPS、拉曼光谱和钻孔方法等现代研究手段，针对不同冷轧薄钢板表面粗糙度Ra、Rz、Rsm和Rpc等物理特性差异以及覆膜加热区的无锡钢板表面铬水合氧化物结构转变，研究PET膜表面内应力演变及其影响因素。在分析典型环境中无锡钢板表面PET膜的表面内应力衰减和化学键演变的基础上，揭示不同铬水合氧化物结构对PET膜老化机制的影响规律。以上研究，将为掌握覆膜机理、推进覆膜铁的发展，提供理论支撑。

覆膜铁具有高效、低能耗、绿色环保和优异的耐腐蚀性能，在DRD冲压罐、DI冲拔罐、易开盖等包装材料领域有着广泛应用。但对冷轧薄钢板/无锡钢板表面覆膜机理与关键控制技术认知度低成为限制覆膜铁发展的瓶颈问题。. 本项目通过冷轧薄钢板表面的本征物理特性演变，明确了冷轧基板耐蚀性与峰值数（Rpc）和还原谷深（Rvk）与冷轧基板耐蚀性有较好的相关性。指出了镀铬铁表面氧化膜中2Cr(OH)3·H2O、Cr(OH)3、Cr2O3、CrOOH和金属铬等各成分比例变化影响因素。首次提出了镀铬层致密性评价指标：优-孔隙率<1.0mg/dm2；良-孔隙率1.0～1.5mg/dm2；差-孔隙率1.5～2.5mg/dm2；劣-孔隙率>2.5mg/dm2，其可快速对镀铬板表面致密性做出准确的评价。首次确定了镀液pH是影响容纳离子能力的关键因素。随着pH的增加，离子生成沉淀反应的吉布斯自由能逐渐减小，镀液容纳杂质离子能力大幅度降低。电镀条件下，更容易使Fe3+、Al3+、Ti3+生成相应的沉淀。电流密度是离子产生沉淀的重要因素，随着电流密度的增加，含有Fe3+、Al3+、Ti3+的镀液pH逐渐降低，各离子生成沉淀反应的吉布斯自由能变大，对自身结晶产生沉淀有抑制作用。. 开发了冷轧基板表面活性表征方法，以化学浸蚀法为依据，以溶液组成NH4SCN，CH3COOH，H2O2和H2O可表征基板表面的化学活性。建立了镀铬铁表面能与PET膜表面内应力之间关系。对于NH4F体系，镀铬板表面镀层中Cr(OH)3含量占比33.94%，H2O占比25.79%；对于H2SiF6体系，镀铬板表面镀层中Cr(OH)3含量占比49.28%，H2O占比18.74%；对于Na2SiF6体系，镀铬板表面镀层中Cr(OH)3含量占比38.16%，H2O占比21.63%。镀层中的H2O对其表面的结合力不利，Cr(OH)3对镀铬板与有机膜的结合有利。随着电流密度的升高，结晶水含量降低。. 掌握了镀铬铁表面功能化PET膜的老化机制。随着环境温度的提高，镀铬板表面的Cr(OH)3转变为Cr2O3，使得Cr(OH)3的含量减小，Cr2O3的含量增加导致镀铬板与有机膜的结合能力较差。. 以上研究，将为掌握覆膜机理、推进覆膜铁的发展，提供理论支撑。