| 摘要: |
| 针对马氏体沉淀硬化不锈钢 15-5PH（0Cr15Ni5Cu4Nb）在海水环境中易腐蚀磨损的问题，采用直流磁控溅射的方法在 15-5PH 钢样片上制备调制周期分别为 940、375 和 234 nm 的掺杂 Cr 的类石墨碳基多层膜（分别标记为 Cr / GLC-S1、 Cr / GLC-S2 和 Cr / GLC-S3），采用扫描电子显微镜（SEM）、拉曼光谱仪（Raman）、MFT-5000 多功能摩擦磨损试验机等仪器设备系统考察三种类石墨碳基多层薄膜的结构及摩擦学性能。研究结果表明：不同调制周期的类石墨多层膜表面均呈现“菜花状”形貌，随着调制周期的减小，“菜花状”颗粒逐渐减小，膜层变得致密；sp2 键含量逐渐增大，石墨化程度加剧，机械性能更加优异。在干摩擦条件下，调制周期适中的 Cr / GLC-S2 薄膜具有良好的减摩耐磨性能，磨损形式以磨粒磨损为主， 而调制周期较大的 Cr / GLC-S1 和调制周期较小的 Cr / GLC-S3 薄膜，在高载荷下均发生不同程度的脆性剥落，导致其摩擦学性能劣化。在人工海水环境中，Cr / GLC-S1 和 Cr / GLC-S2 薄膜在中低载荷下的摩擦学性能较好，磨损形式仍以磨粒磨损为主，在高载荷下三种多层膜均发生不同程度的脆性剥落，特别是调制周期较小的 Cr / GLC-S3 薄膜已失效。针对不同的工况， 设计合理的调制周期是提高 GLC 薄膜摩擦学性能的关键，结果可为类石墨碳基薄膜在海洋防护中的实际应用提供一定参考。 |
| 关键词: 磁控溅射 类石墨多层膜 调制周期 摩擦磨损 15-5PH 不锈钢 |
| DOI：10.11933/j.issn.1007?9289.20221203002 |
| 分类号:TH117 |
| 基金项目:外专局引智（HNGD2020003）；国家自然科学基金（52275186）资助项目 |
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| Structural Design and Tribological Behavior of Graphite-like Carbon Multilayer Films on 15-5PH Stainless Steel |
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LI Yingchun1,2, YANG Gengsheng1, NIE Aonan1, QIU Ming1,2, FAN Henghua1
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1.School of Mechanical and Electrical Engineering,Henan University of Science and Technology, Luoyang 471003 , China;2.Collaborative Innovation Center of Machinery Equipment Advanced Manufacturing of Henan Province,Henan University of Science and Technology, Luoyang 471003 , China
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| Abstract: |
| Martensitic precipitation-hardened stainless steel 15-5PH (0Cr15Ni5Cu4Nb) is used for some critical mechanical moving parts in marine equipment, including connecting rods and shafts, which function in the seawater environment for a long time, and are subjected to the dual effects of friction and corrosion. The tribological properties of these moving parts in seawater environment significantly affect the safety and durability of marine engineering equipment. An effective way to improve their tribological properties involves preparing a protective layer of antifriction and wear-resistant coatings on the surface of the friction pair. However, conventional organic protective coatings can not meet the corresponding requirements because seawater is a strong corrosive medium. In this study, to address the problem of corrosion-wear of 15-5PH in seawater environment, Cr / GLC multilayer films with modulation periods of 940, 375, and 234 nm (marked as Cr / GLC-S1, Cr / GLC-S2, and Cr / GLC-S3, respectively) were deposited on 15-5PH stainless steel using DC magnetron sputtering. The structure and tribological properties of the graphite-like carbon films were investigated using scanning electron microscopy, Raman spectroscopy, and an MFT-5000 multifunctional tribometer, among other instruments. From the results, the surfaces of the graphite-like carbon multilayer films with different modulation periods present obvious cauliflower-like particle morphology. As the modulation period decreased, the size of the cauliflower-like particles gradually decreased, the film became denser, and the surface roughness of the multilayer films increased. With a decrease in the modulation period, the content of sp2 bond increased gradually, the degree of graphitization intensified; and the adhesion, hardness, and elastic modulus of the graphite-like carbon films increased gradually, resulting in excellent mechanical properties. Under dry friction, the Cr / GLC-S2 film with a moderate modulation period exhibited better tribological properties, and its wear form was abrasive. However, the Cr / GLC-S1 film with larger modulation period and Cr / GLC-S3 film with smaller modulation period exhibited different degrees of brittle spalling at high loads, resulting in direct contact between the substrate and the couple ball, which resulted in a higher wear rate and poor tribological properties. Under an artificial seawater environment, owing to the lubrication of seawater and the formation of transfer film, the friction coefficients of the three types of graphite-like multilayer films were significantly lower than those of dry friction. The tribological properties of Cr / GLC-S1 and Cr / GLC-S2 were better at medium and low loads. In addition, the wear form remained predominantly abrasive wear because the thicker GLC surface layer produced a good solid lubrication effect, and the formation of penetrating corrosion channels in the film was delayed, resulting in slight wear. However, the three types of multilayer films exhibited different degrees of brittle spalling at high loads. The Cr / GLC-S3 film with a small modulation period was worn out, a large area of the substrate was exposed, and the film was seriously damaged, losing its protective effect on the substrate. Because of the thinner depth of the GLC and Cr sublayers, the longitudinal growth gap formed in the deposition process quickly developed into longitudinal cracks under the interaction of the reciprocating load and corrosion of seawater. Longitudinal cracks quickly penetrated the entire film into the substrate, forming penetrating corrosion channels. Seawater along these etching channels penetrate through the entire film to the matrix, and the combination of the substrate and interlayer is weakened, resulting in serious spalling. Therefore, the design of a reasonable modulation period is the key to improving the tribological properties of GLC films under different working conditions. These results provide a reference for the practical application of graphite-like carbon films in marine protection. |
| Key words: magnetron sputtering graphite-like carbon multilayer films modulation period friction and wear 15-5PH stainless steel |
