摘要: |
铝在钢表面的润湿行为及润湿性直接关系到热浸铝工艺所制备涂层的质量。采用座滴法在高真空条件下研究了熔融4043和6061铝合金分别在Q235钢表面的润湿行为及界面结构。结果表明:4043/6061铝-Q235钢为典型的反应润湿体系,且润湿性随着温度的升高而改善。反应过程中生成的金属间化合物替代基板表面的氧化膜,形成洁净的界面进而促进熔滴铺展。铝合金化学成分不同导致界面结构不同,进一步导致铺展动力学规律不同,其中6061和4043铝合金在Q235钢表面润湿的活化能分别为86 kJ/mol和8 kJ/mol。6061铝合金中Mg的挥发可以还原钢表面的氧化膜,使铝熔滴更容易润湿钢板并形成前驱膜,其形成机制为“皮下渗透机制”。4043铝合金中的Si在固-液界面有较高的亲和力,因此在反应层出现了明显的Si富集。 |
关键词: 界面 反应润湿 毛细力 表面改性 前驱膜 |
DOI:10.11933/j.issn.1007-9289.2016.05.015 |
分类号: |
基金项目:国家自然科学基金(51665031) |
|
Reactive Wetting Behavior of Q235 Steel by Molten 4043/6061 Al Alloys and Formation Mechanism of Precursor Film |
JIN Peng, LIN Qiao-li, CAO Rui, CHEN Jian-hong
|
State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050
|
Abstract: |
Wetting behavior and final wettability of steel by molten Al directly determine the quality of the coating in the hot dip aluminizing process. In this study, wetting of Q235 steel by two industrial grades Al alloys (4043 and 6061) was investigated by the modified sessile drop method at temperatures between 600 and 750℃ under high vacuum. Al alloys (4063 and 6061)-Q235 steel is typical reactive wetting, and the wettability was improved with the increase of the temperature. The formation of intermetallics leads to the replacement of the oxidized surface by a clean surface, and further induces the spreading. Different chemical compositions in Al alloys also lead to the different interfacial structures and spreading dynamics, and the activation energies for wetting of Q235 steel by molten 6061 and 4043 Al alloys are 86 kJ/mol and 8 kJ/mol, respectively. The Mg in 6061 Al alloy reduces the oxide film and then makes molten Al infiltrate into the steel substrate easily, as a subcutaneous infiltration mechanism. The high affinity of the Si in 4043 Al alloy at Al-steel interface induces the segregation of Si in the reaction layer. |
Key words: interface reactive wetting capillarity surface modification precursor film |