Bi对锌液与X80钢表面润湿性的影响

通过改良静滴法研究Zn-xBi(x=0.5,1.0,1.5,2.0)合金熔体在450℃下与不同基板的润湿行为，对润湿反应之后的表面张力进行计算，并使用扫描电镜能谱仪(SEM-EDS)分析润湿试验后的试样表面及截面的微观形貌和组织结构。结果表明，在450℃下，Zn-Bi合金表面张力随Bi含量增加呈现先减小再增大的规律。Zn-1.0Bi合金熔体与X80钢的接触角最小，表明添加1.0%Bi(质量分数)后的锌液润湿性最好。Zn-Bi合金熔体中Bi的含量对界面反应强度和界面结构产生影响，进而减小表面张力和接触角。润湿初期Bi元素的快速吸附降低锌液表面张力，使接触角减小。中期由界面反应强度控制，此时形成前驱膜且其促进锌合金熔体在钢基板的流动，从而改善润湿性。

Effect of Bi on surface wettability of molten zinc and X80 steel

Wetting behavior of Zn-xBi alloy melts (x=0.5, 1.0, 1.5, 2.0) with different substrates at 450 ℃ was studied by improved sessile drop method, and the surface tensions after wetting reaction were calculated. The morphology and structure of the surface and cross-section of the specimens after the wetting reaction were analyzed by means of scanning electron microscope-energy dispersive spectrometer (SEM-EDS). The results show that the surface tension of Zn-Bi alloy melts at 450 ℃ decreases first and then increases with the increase of Bi content. The contact angle between the Zn-1.0Bi alloy melt and X80 steel is the smallest, indicating that the wettability of molten zinc is the best after adding 1.0%Bi (mass fraction). The content of Bi in the Zn-Bi alloy melt affects the interfacial reaction intensity and interface structure, thereby reducing the surface tension and contact angle. The rapid adsorption of Bi element at the initial stage of wetting reduces the surface tension of molten zinc and reduces the contact angle. In the middle stage, it is controlled by the interfacial reaction intensity, which forms a precursor film and promotes the flow of zinc alloy melt on the steel substrate, thereby improving the wettability.