目的 改善铝基材料在干摩擦条件下的摩擦磨损性能。 方法 采用两步法在铝表面构筑稳定的超疏水薄膜。 首先采用盐酸溶液刻蚀金属铝,在其表面构筑微纳织构;然后涂覆硬脂酸,降低表面能。利用 SEM、XRD、FTIR、接触角测量仪及摩擦磨损试验机表征铝表面超疏水薄膜的表面形貌、化学组分、润湿性和减摩耐磨特性。 结果 SEM 及 XRD 分析表明,刻蚀后的铝表面呈现多尺度微纳结构。 FTIR 分析表明,脂肪酸以双配位结构与铝表面发生作用。 接触角测试表明,所制备的薄膜呈现出良好的超疏水性能,静态接触角达 150°,滑动角小于 10°。 摩擦学实验结果表明,制备的超疏水薄膜可明显改善铝基底的摩擦学性能,在干摩擦条件下与钢球对磨时,超疏水薄膜的摩擦系数保持在 0. 16 左右,寿命超过 10 000 s,而相同条件下未处理的金属铝摩擦系数超过 0. 6。 结论 采用盐酸溶液刻蚀金属铝,然后涂覆硬脂酸,可在铝表面构筑复合薄膜。 薄膜不仅表现出明显的超疏水特性,同时具有良好的减摩耐磨性能。 该方法技术简单,价格低廉,易于批量化生产,为改善微纳条件下铝及其合金的摩擦学性能提供了一个新的思路。

Objective To improve the friction and wear performance of aluminum in dry sliding contact. Methods The two-step method was used in this paper to fabricate the superhydrophobic film on aluminum. The aluminum substrate was firstly etched by hydrochloric acid to create the micro- and nano-texture, then coated by layer of stearic acid to decrease surface energy. SEM, XRD, FTIR spectroscopy, contact-angle measuring instrument and friction-abrasion testing machine were used to analyze the morphological features, chemical composition, hydrophobicity and tribological performance of superhydrophobic film on aluminum, respectively. Results SEM and XRD analyses showed that the micro- and nano-structure was created on aluminum after chemical etch. FIIR analysis showed stearic acid was chemically absorbed on aluminum surface in a bidentate mode. The film on aluminum showed superhydrophobicity with static water contact angle of 150° and sliding angle of 10°. It was effective to improve tribological performance of aluminum. The friction coefficient kept as low as 0. 16 for 10 000 s sliding time when sliding with steel ball in the unlubricated condition. Conclusion The superhydrophobic film formed on aluminum by using chemical etch by hydrochloric acid and then the surface modified by stearic acid could improve the friction and wear performance of aluminum. The method is simple and can be easily operated at a large scale. It may provide a new method to improve the friction and wear performance of aluminum.