Self-ion irradiation on hydrogenated amorphous carbon films at depth of adhesion interlayer: Radiation-induced atomic intermixing and degraded film properties |
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Authors: | Jiao Xu Li Qiao Zewen Duan Dengji Guo Liqiang Chai Xiaoyu Zhao Peng Wang Weimin Liu |
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Institution: | 1. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, China;2. Institute of Semiconductor Manufacturing Research, Shenzhen University, Shenzhen, China |
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Abstract: | Hydrogenated amorphous carbon (a-C:H) films consisting of a top a-C:H layer, a gradient transient a-C:H:Ti layer, and a bottom Ti layer were irradiated by 1.1-MeV C+ ions, resulting in a maximum displacement damage of 1.0 dpa and a projected range inside the Ti layer. Time-of-flight secondary ion mass spectrometry, electron energy loss spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy analyses were performed to investigate the compositional and structural transitions of a-C:H films after self-ion irradiation. The results revealed that C+ ions passing through the top a-C:H layer induced C–H fracture and hydrogen diffusion in this layer and then resulted in atomic intermixing in the multilayered adhesion interlayer. After local energy deposition of C+ ions, the initial sharp interfaces in the a-C:H:Ti layer became ambiguous due to interfacial mixing. In addition, titanium carbides formed in the Ti layer, with a gradual phase transition from TiCx to TiC with a diffusion depth of 200 nm. The broken compositional gradients of the adhesion interlayer resulted in a significant decrease in the adhesion strength of the films, which eventually resulted in degraded antiwear properties of the irradiated film in dry sliding tribotests. |
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Keywords: | adhesion strengths atomic intermixing properties degradations self-ion irradiation structural transitions |
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