稀有金属

针对传统超双疏表面耐磨性差及凹角结构制备复杂等问题，本文提出了一种结合激光氮化织构与阳极氧化的两步策略，用于制备钛合金超双疏表面。采用金相显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、 X射线衍射(XRD)及X射线光电子能谱(XPS)对其微观组织进行了表征分析。结果表明：利用激光氮化织构复合阳极氧化技术制备的超双疏表面，其水接触角达165°，花生油接触角达156°。超双疏表面微结构顶端主要由Ti O₂组成，并含有少量的TiON和TiN。阳极氧化生成的TiO₂并破坏激光原有TiN形貌，其表面的凹角结构由腐蚀性F~-对TiO₂的蚀刻溶解形成。磨损主要影响顶层结构，但因TiN的高硬度和氧化层的保护，以及氧化层的保护作用，超双疏表面在10次摩擦循环后，水接触角仍保持在146°，油接触角为130°。本文研究成果为优化超双疏表面制备工艺、提升其应用性能与可靠性提供了参考。

Titanium alloy has been widely used in many fields such as shipbuilding, aviation, military, and the petroleum industry due to its low density, high toughness, and excellent corrosion resistance. However, the wear resistance of TC4 titanium alloy have been insufficient, which limites its service life. With the advancement of surface modification technology, researchers have developed surfaces with multiple functions by manufacturing micro-nano structures on metal surfaces. In particular, superamphiphobic surfaces with superhydrophobic and superoleophobic properties have attracted much attention due to their ability to repel liquids with low surface energy. The superamphiphobic surface is characterized by a droplet contact angle greater than 150°, which keeps the droplets spherical and left no traces when the surface rolled or slid. It has shown potential application value in improving corrosion resistance, preventing icing, and self-cleaning. The formation of a superamphiphobic surface on titanium alloy have not only expanded its application range but also solved the problem that the super-hydrophobic surface is easy to lose its performance when contacting oily liquids. However, the wear resistance of the superamphiphobic surface obtained by traditional preparation methods have remained insufficient, and it is easily destroyed under external forces such as friction. Additionally, the preparation technology of titanium alloy superamphiphobic surfaces, such as lithography and chemical/electrochemical etching, has suffered from high cost and difficult morphology control. Laser nitriding technology has been able to generate a hard nitriding layer, which could effectively improve the wear resistance of the surface. Anodic oxidation technology has been used to prepare concave corner structures on titanium alloy surfaces. However, the structures prepared by this method are shallow, their growth direction cannot be controlled, and their wear resistance is poor. This paper adopted a two-step design strategy. First, a regular micron-scale array structure had been prepared on the titanium alloy surface by laser nitriding texture technology. Then, a concave angle structure was further fabricated through composite anodic oxidation technology, ultimately obtaining a superamphiphobic surface on titanium alloy. In this study, the formation mechanism and wettability transformation mechanism of the concave corner structure were studied, and its wear resistance was discussed through friction and wear experiments. The formation state, thickness, and cross-section changes of the nitrided layer after laser nitriding, texture, and composite anodizing treatment had been analyzed by metallographic microscopy. Scanning electron microscopy(SEM) had been employed to analyze the surface and cross-section of the sample accurately, while the post-wear surface morphology had been recorded and characterized. The elemental distribution and content of the superamphiphobic surface had been tested and analyzed by energy dispersive spectroscopy(EDS). The phase composition of the sample surface had been determined by X-ray diffraction(XRD), and the elemental composition had been identified by X-ray photoelectron spectroscopy(XPS). The static contact angle of the sample surface had been measured by a contact angle goniometer, and the surface wear resistance had been evaluated using a self-built friction and wear testing device. The superhydrophobic surface with a contact angle of 160° was prepared by laser nitriding texture technology. The cross-sectional microstructure of the nitrided layer exhibited a cellular crystal morphology, which was characterized by a gradual decrease in the size of the cellular crystal as the depth of the nitrided layer increased. Furthermore, the superamphiphobic surfaces with a water contact angle of 165° and a peanut oil contact angle of 156° were prepared by anodic oxidation. The concave corner structure was mainly composed of TiO₂, and the anodic oxidation treatment did not change the original microstructure of TiN. The formation of this structure was mainly attributed to the selective erosion of the oxide layer by corrosive fluoride ions. The silane group in the fluorosilane molecule reacted with the hydroxyl group on the surface of the material to form a stable silicon-oxygen bond, so that it was firmly fixed on the surface of the material, while the low surface energy-CF₃ and-CF₂ groups inside the fluorosilane were oriented outside the surface of the material, forming an orderly molecular arrangement, thereby reducing the surface energy of the material. XRD results showed that after laser nitriding texture treatment, obvious TiN characteristic peaks appeared on the surface of the sample, which confirmed the successful formation of TiN structure on the surface. After anodic oxidation treatment, the surface of the sample retained the characteristic peak of TiN crystal structure, indicating that anodic oxidation mainly affected the surface layer, had little effect on the internal crystal structure, and maintained the integrity of the micro-texture. The superhydrophobic surface lost its superhydrophobicity after 6 friction cycles, and the contact angle decreased to 140° after 10 friction cycles. The superamphiphobic surface lost superhydrophobicity after 9 friction cycles. After 10 friction cycles, the water contact angle was 146°, and the oil contact angle was 130°. The micro-nano composite hierarchical structure enhanced the wear resistance of the titanium alloy. This study provided a theoretical basis for optimizing the preparation process of superamphiphobic surfaces and helped to enhance their performance stability and reliability in engineering applications.