| 1. |
- Wu, Zhengtao, et al.
(author)
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Improving oxidation and wear resistance of TiB2 films by nano-multilayering with Cr
- 2022
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In: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 436
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Journal article (peer-reviewed)abstract
- Alternating TiB2-DCMS and Cr-HiPIMS layers are used to fabricate TiB2/Cr multilayer films with varying the Cr-interlayer thickness, 2 and 5 nm, and the substrate bias during growth of Cr interlayers from floating, to -60 V and -200 V. The effects of multilayer structure on mechanical properties, static oxidation, and tribological behavior of the TiB2/Cr multilayers are investigated. The results reveal that TiB2 nanocolumns renucleate at each Cr interface maintaining smooth film surface and film density. Interlaying with Cr with thicknesses of 2-5 nm improves the resistance to oxidation at 500-600 ?& nbsp;as compared to TiB2 monolayer. The increase of the thickness of the Cr interlayers from 2 to 5 nm decreases the hardness of the multilayer slightly but deteriorates the wear rate significantly. The friction coefficients at 500 ?& nbsp;are lower than those at RT due to boric acid liquid lubrication induced by surface oxidation. The TiB2/Cr multilayer films show higher wear resistance than TiB2 monolayer. The multilayer films with 2 nm-thick Cr deposited at -60 V have the lowest recorded wear rates. Irradiation with 200 eV Cr+ leads to interface mixing, resulting in the formation of B-deficient TiBx phase (x < 2) and higher wear rates compared to multilayers grown at -60 V.
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| 2. |
- Wu, Zhengtao, et al.
(author)
-
Investigation on plastic deformation of arc-evaporated AlCrSiN and AlCrSiON nanocomposite films by indentation
- 2022
-
In: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 441
-
Journal article (peer-reviewed)abstract
- Nanoindentation produced plastic deformation of arc-evaporated AlCrSiN and AlCrSiON nanocomposite films deposited on cemented-carbide substrates was investigated. The nanoindentation tests have the maximum penetration depth of 250 nm. Microstructure evolution in the indents was indicated by focused-ion-beam cutting and transmission-electron-microscopy observation. The results indicate that both the AlCrSiN and the AlCrSiON nanocomposite films exhibit excellent plasticity without the occurrence of microcrack initiation and propagation in the indents and grain boundaries. The prominent pile-up phenomenon produced by plastic flow was observed in the indent of the AlCrSiON film. Incorporating O into the AlCrSiN reduces both hardness and toughness of the film. This produces the pile-up in the AlCrSiON film when exposed to a nanoindenter. Rotation of the (Cr, Al)N nanograins and deflection of self-organized multilayer interface contribute to the plastic deformation of the AlCrSiN. However, shear band, interface deflection, and grain rotation contribute to the nanoindentationinduced plastic deformation of the AlCrSiON film.
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| 3. |
- Wu, Zhengtao, et al.
(author)
-
Reprint of: Improving oxidation and wear resistance of TiB2 films by nano-multilayering with Cr*
- 2022
-
In: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 442
-
Journal article (peer-reviewed)abstract
- Alternating TiB2-DCMS and Cr-HiPIMS layers are used to fabricate TiB2/Cr multilayer films with varying the Cr interlayer thickness, 2 and 5 nm, and the substrate bias during growth of Cr interlayers from floating, to -60 V and -200 V. The effects of multilayer structure on mechanical properties, static oxidation, and tribological behavior of the TiB2/Cr multilayers are investigated. The results reveal that TiB2 nanocolumns renucleate at each Cr interface maintaining smooth film surface and film density. Interlaying with Cr with thicknesses of 2-5 nm improves the resistance to oxidation at 500-600 degrees C as compared to TiB2 monolayer. The increase of the thickness of the Cr interlayers from 2 to 5 nm decreases the hardness of the multilayer slightly but deteriorates the wear rate significantly. The friction coefficients at 500 degrees C are lower than those at RT due to boric acid liquid lubrication induced by surface oxidation. The TiB2/Cr multilayer films show higher wear resistance than TiB2 monolayer. The multilayer films with 2 nm-thick Cr deposited at -60 V have the lowest recorded wear rates. Irradiation with 200 eV Cr+ leads to interface mixing, resulting in the formation of B-deficient TiBx phase (x < 2) and higher wear rates compared to multilayers grown at -60 V.
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| 4. |
- Zhao, Mingyue, et al.
(author)
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Advances in Two-Dimensional Materials for Optoelectronics Applications
- 2022
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In: Crystals. - : MDPI. - 2073-4352. ; 12:8
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Research review (peer-reviewed)abstract
- The past one and a half decades have witnessed the tremendous progress of two-dimensional (2D) crystals, including graphene, transition-metal dichalcogenides, black phosphorus, MXenes, hexagonal boron nitride, etc., in a variety of fields. The key to their success is their unique structural, electrical, mechanical and optical properties. Herein, this paper gives a comprehensive summary on the recent advances in 2D materials for optoelectronic approaches with the emphasis on the morphology and structure, optical properties, synthesis methods, as well as detailed optoelectronic applications. Additionally, the challenges and perspectives in the current development of 2D materials are also summarized and indicated. Therefore, this review can provide a reference for further explorations and innovations of 2D material-based optoelectronics devices.
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