Load-dependent high temperature tribological properties of silver tantalate coatings
Load-dependent high temperature tribological properties of silver tantalate coatings
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DOI：
10.1016/j.surfcoat.2014.01.046
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发表时间：
2014-04
影响因子：
5.4
通讯作者：
D. Stone;Hongyu Gao;C. Chantharangsi;Chutima Paksunchai-;M. Bischof;D. Jaeger;A. Martini;T. Scharf;S. Aouadi
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文献类型：
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作者：
D. Stone;Hongyu Gao;C. Chantharangsi;Chutima Paksunchai-;M. Bischof;D. Jaeger;A. Martini;T. Scharf;S. Aouadi
钽酸银涂层是通过反应不平衡磁控溅射从银和钽源生产的，作为潜在的高温固体润滑剂。这些薄膜在 750°C 的温度下在 1、2、5 或 10 N 的正常载荷下针对 Si3N4 配合面进行了磨损测试。这些滑动测试表明，随着载荷的增加，摩擦力单调增加。使用扫描俄歇纳米探针、原子探针断层扫描和横截面透射电子显微镜等技术对磨损轨迹的表面和亚表面区域进行系统研究，揭示了随着负载增加的以下趋势：（1）磨损轨迹表面的银含量减少； (2)由于AgTaO3重构形成Ta2O5和Ag而形成的机械混合层的厚度减小； (3) 由于 Ag 从原始 AgTaO3 基体中分离和迁移，在整个摩擦膜中形成了多孔结构。这些结果得到了分子动力学模拟的补充，证实了摩擦随负载的增加。此外，模拟支持这样的假设：这种趋势可以用滑动表面附近银簇的减少以及相关的孔隙率降低来解释。
Silver tantalate coatings were produced by reactive unbalanced magnetron sputtering from silver and tantalum sources as potential high temperature solid lubricants. The films were wear-tested at 750 °C under normal loads of 1, 2, 5, or 10 N against a Si3N4counterface. These sliding tests revealed that the friction monotonically increased as the load was increased. A systematic investigation of the surface and sub-surface regions of the wear track, using techniques such as Scanning Auger Nanoprobe, Atom Probe Tomography, and cross-sectional transmission electron microscopy, revealed the following trends with increasing load: (1) a decrease in the amount of Ag on the surface of the wear track; (2) a decrease in the thickness of the mechanically mixed layer that forms as a result of the reconstruction of AgTaO3to form Ta2O5and Ag; and (3) the formation of a porous structure throughout the tribofilm as a result of the segregation and migration of Ag from the original AgTaO3matrix. These results were complemented by molecular dynamics simulations, which confirmed the increase of friction with load. Further, the simulations support the hypothesis that this trend can be explained in terms of decreased presence of Ag clusters near the sliding surface and the associated decreased porosity.