Toward low friction in water for Mo2N/Ag coatings by tailoring the wettability
Toward low friction in water for Mo2N/Ag coatings by tailoring the wettability
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通过调整润湿性来实现 Mo2N/Ag 涂层在水中的低摩擦
DOI：
10.1016/j.apsusc.2018.04.041
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发表时间：
2018
影响因子：
6.7
通讯作者：
Zhang Kan
中科院分区：
文献类型：
--
作者：
Dai Xuan;Wen Mao;Huang Keke;Wang Xin;Yang Lina;Wang Jia;Zhang Kan
在腐蚀、磨损和海水等恶劣条件下对坚固表面的需求不断增加，刺激了自润滑保护涂层的发展。与此同时，由于石油危机，水润滑的研究再次引起了学术界和工程界的广泛关注。通过提高Ag含量，Mo 2N/Ag涂层具有较高的亲水性，同时在水环境中的摩擦系数显著下降。为此，通过共溅射沉积具有不同Ag含量的Mo 2N/Ag涂层，其表现出由嵌入Mo 2N基体中的沉淀Ag组成的纳米复合结构。高亲水性可归因于Mo 2N的部分氧化和Ag沉淀的高极性的组合贡献。胶体摩擦产物和双电层模式说明摩擦系数的降低。其中，增强的亲水性将导致在配对物与涂层之间形成薄的“水膜”层。Mo_2N/Ag在水中滑动时水解生成的MoOx/Ag_2Mo_4O_（13）可作为润滑相。同时，这些带负电荷的MoOx/Ag 2 Mo 4 O 13胶体粒子诱导“水膜”中正离子重排，形成双电层，也有助于摩擦系数的降低。
Increasing demands for robust surfaces in harsh conditions, such as erosion, abrasion and sea-water, has stimulated the development of self-lubricated protective coatings. Meanwhile, due to the oil crisis, research in water lubrication again attracts much attention from both academics and practical engineers. Here, a higher hydrophilicity accompanying with a remarkable drop of friction coefficient in water environment was achieved successfully in Mo2N/Ag coatings by increasing Ag content. To do these, the Mo2N/Ag coatings with different Ag content were deposited by co-sputtering, which exhibit a nanocomposite structure consisting of precipitate Ag embedded in the Mo2N matrix. The high hydrophilicity can be ascribed to the combined contributions of the partial oxidation of Mo2N and high polarity of Ag precipitates. The decrease of friction coefficient is illustrated by the colloidal friction products and a mode with electric double layer. In which, enhanced hydrophilicity will result in forming a thin “water film” layer between the interface of counterpart and the coatings. And the MoOx/Ag2Mo4O13derived from the hydrolysis action of Mo2N/Ag sliding in water could function as lubricant phase. Meanwhile, these negative charged MoOx/Ag2Mo4O13colloidal particles induce the rearrangement of positive ions in the “water film” and form an electric double layer, which also contributes to the decrease of friction coefficient.