刘汉麟,徐前刚,林浩.铝硅熔体与镀覆Q235钢的润湿行为[J].表面技术,2023,52(2):352-359, 368.
LIU Han-lin,XU Qian-gang,LIN Hao.Wetting Behavior of Al-Si Melt and Coated Q235 Steel[J].Surface Technology,2023,52(2):352-359, 368 |
| 铝硅熔体与镀覆Q235钢的润湿行为 |
| Wetting Behavior of Al-Si Melt and Coated Q235 Steel |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.02.033 |
| 中文关键词: Q235钢 铝硅熔体 锡锌合金镀层 润湿性 接触角 铺展 |
| 英文关键词:Q235 steel Al-Si melt tin-zinc alloy coating wettability contact angle spreading |
| 基金项目:国家自然科学基金(50704001) |
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| 中文摘要: |
| 目的 探究锡锌合金镀层对铝硅熔体与Q235钢润湿行为的影响。方法 通过磁控溅射法和热浸镀法在Q235钢基底表面镀覆不同厚度(190~5 500 nm)的锡锌合金镀层。采用改良座滴法测试700 ℃下铝硅熔体与不同表面处理的Q235钢基底的润湿行为。利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)对凝固润湿试样截面和表面组织及成分进行表征分析。结果 700 ℃时铝硅熔体与未镀覆基底为部分润湿，初始接触角和终态接触角分别为88°和66°。施加190 nm锡锌合金镀层后，初始铺展速率明显增大，终态接触角约为13°，并在铺展前沿形成前驱膜;随着镀层厚度的增加，终态接触角减小，熔体铺展速率及前驱膜宽度增大，1 680 nm时趋于完全润湿(终态接触角约为2°)。铝硅熔体与未镀覆钢基底界面反应产物为Fe2Al5相和Al8Fe2Si相，反应层垂直界面向熔体侧快速生长而隔离熔体铺展前沿与基底的接触。施加镀层会促进反应层(Fe2Al5相和Al8Fe2Si相)沿铺展前沿快速生长，前驱膜表层主要为Al8Fe2Si相。镀层过厚(5 500 nm)的凝固润湿试样界面附近存在分离的低熔点锡相。结论 锡锌合金镀层主要通过改变界面反应层生长及润湿三相线组态而影响铝硅熔体与Q235钢的润湿行为。锡锌合金镀层能有效改善铝硅熔体与Q235钢的润湿性，有助于铺展前沿前驱膜的形成。随着镀层厚度的增加，熔体铺展速率增大，终态接触角减小。趋于完全润湿(1 680 nm镀层)后继续增大镀层厚度对润湿行为无明显影响，但过厚的镀层会促进低熔点锡相在凝固界面附近形成，这会弱化界面结合。 |
| 英文摘要: |
| To explore the effect of Sn-Zn alloy coating on the wetting behavior of Al-Si melt and Q235 steel, in this paper, an improved sessile drop method was used to study the wetting of Al-Si melt on uncoated Q235 steel substrate and coated Q235 steel substrates with different coating thickness at 700 ℃. Various thicknesses (190-5 500 nm) of Sn-Zn alloy coatings were deposited on the surface of Q235 steel substrate by magnetron sputtering and hot-dip plating. Scanning electron microscope (SEM) and energy dispersive X-ray (EDS) were used to characterize and analyze the composition and microstructures at the cross-section and surface of the solidified wetting sample. Experimental results showed that the Al-Si melt and the uncoated substrate were partially wetted at 700 ℃, and the initial and final contact angles were 88° and 66°, respectively. By applying 190 nm Sn-Zn alloy coating on the steel substrate, the initial spreading rate increased significantly and the final contact angle was about 13°, and a precursor film was formed at the spreading front of molten Al-Si alloy on the coated Q235 steel substrate. With the increase of the coating thickness, in the wetting of Al-Si alloy melt on coated Q235 steel substrate, the final contact angle decreased, the melt spreading rate and the width of the precursor film increased, and it tended to be completely wetted at 1 680 nm coated substrate(the final contact angle was about 2°). The interfacial reaction products between Al-Si melt and uncoated steel substrate were Fe2Al5 phase adhering to the substrate side and Al8Fe2Si phase close to the melt side. The reactive layer grew rapidly towards the melt side perpendicular to the interface, which isolated the contact of the melt spreading front with the substrate and inhibited the melt spreading. The application of the Sn-Zn alloy coating promoted the rapid growth of the reaction layers (Fe2Al5 phase and Al8Fe2Si phase) along the spreading direction on the coated substrate surface. The surface layer of the precursor film was mainly composed of Al8Fe2Si phase. Some isolated low-melting tin phases exist near the interface of the solidified Al-Si/coated Q235 wetting specimen with an excessively thick coating (5 500 nm). The effect mechanism of Sn-Zn alloy coating on the wetting behavior of Al-Si melt and Q235 steel was analyzed based on interfacial reaction, wetting triple line configuration and wetting driving force. The Sn-Zn coating affects the wetting behavior of Al-Si melt and Q235 steel mainly by changing the growth of the interface reaction layer and the configuration of the triple wetting line. The tin-zinc alloy coating can effectively improve the wettability of Al-Si melt and Q235 steel, and contribute to the formation of the precursor film at the spreading front. As the coating thickness increases, the melt spreading rate increases and the final contact angle decreases. Continuing to increase the coating thickness after tending to complete wetting (Al-Si/1 680 nm coated steel substrate) has no significant effect on the wetting behavior, but an excessively thick coating will promote the formation of a low melting point tin phase near the solidification interface, which will weaken the interface bonding. |
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