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- Nano-diamond composite coatings researcherPlease, don't hesitate to contact me for cooperation in research filed of d... moreNano-diamond composite coatings researcherPlease, don't hesitate to contact me for cooperation in research filed of deposition and characterization of nano-diamond composite coatings/films for mechanical and tribological applications. The films characterization includes hardness, elastic modulus, and adhesion, Friction/Wear, EDS/SEM, XPS, HAXPES, XRD.edit
Super-hard nanodiamond composite (NDC) films, synthesized via cathodic arc plasma deposition on unheated WC − Co substrates, offer an eco-friendly solution for cutting tools. A 100 nm-thick Al-interlayer mitigates Co catalytic effects,... more
Super-hard nanodiamond composite (NDC) films, synthesized via cathodic arc plasma deposition on unheated WC − Co substrates, offer an eco-friendly solution for cutting tools. A 100 nm-thick Al-interlayer mitigates Co catalytic effects, improving adhesion and yielding smooth and dense 10 µm-thick films at a deposition rate of 3.3 μm/hr. These grain-boundary-rich nanostructured films, with an impressive 58 GPa hardness attributed to a substantial 70 % C sp 3 fraction, prove optimal for hard coatings. The Al-interlayer effectively suppresses Co catalytic effects, forming a dense Al-oxide layer, enhancing film hardness and adhesion (Lcr = 18.6 N). NDC films present a promising eco-friendly option for high-performance hard coatings.
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Hard amorphous carbon, so-called diamond-like carbon, has attracted attention as a coating material alternative to diamond. In particular, nonhydrogenated amorphous carbon (a-C) films deposited by the filtered cathodic vacuum arc (FCVA)... more
Hard amorphous carbon, so-called diamond-like carbon, has attracted attention as a coating material alternative to diamond. In particular, nonhydrogenated amorphous carbon (a-C) films deposited by the filtered cathodic vacuum arc (FCVA) method and sputtering possess higher hardness than that of hydrogenated amorphous carbon (a-C:H) films prepared by CVD. Hard amorphous carbon films are deposited at low substrate temperatures, and a-C films can be deposited at lower substrate temperatures than a-C:H films prepared by CVD. We have realized the formation of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite (UNCD/a-C) films by coaxial arc plasma deposition (CAPD). UNCD/a-C films comprise a large number of diamond grains with diameters less than 10 nm and an a-C matrix. CAPD is categorized as physical vapor deposition. The deposition of UNCD/a-C films by CAPD has the following distinctive features: i) hydrogen atmospheres are not necessarily required for the growth;...
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Hard X-ray photoemission spectroscopy (HAXPES) was employed for the structural evaluation of ultrananocrystalline diamond/amorphous carbon (UNCD/a-C) composite films deposited on cemented carbide substrates, at substrate temperatures up... more
Hard X-ray photoemission spectroscopy (HAXPES) was employed for the structural evaluation of ultrananocrystalline diamond/amorphous carbon (UNCD/a-C) composite films deposited on cemented carbide substrates, at substrate temperatures up to 550 °C by coaxial arc plasma deposition. The results were compared with those of soft X-ray photoemission spectroscopy (SXPES). Since nanocrystalline diamond grains are easily destroyed by argon ion bombardment, the structural evaluation of UNCD/a-C films, without the argon ion bombardment, is preferable for precise evaluation. For samples that were preserved in a vacuum box after film preparation, the sp3 fraction estimated from HAXPES is in good agreement with that of SXPES. The substrate temperature dependencies also exhibited good correspondence with that of hardness and Young’s modulus of the films. On the other hand, the sp3 fraction estimated from SXPES for samples that were not preserved in the vacuum box had an apparent deviation from tho...
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Abstract Low-temperature fabrication of nanodiamond films on untreated silicon substrates, which are preferred substrates and widely employed in industry, can extend nanodiamond film applications, for instance in biosensing and... more
Abstract Low-temperature fabrication of nanodiamond films on untreated silicon substrates, which are preferred substrates and widely employed in industry, can extend nanodiamond film applications, for instance in biosensing and miniaturization technologies. For its realization, the weak adhesion of nanodiamond films on silicon substrates due to insufficient atomic interdiffusion at the interfaces is a serious issue that needs to be overcome. In the present study, coaxial arc plasma deposition (CAPD) grown nanodiamond films were fabricated at low temperatures on silicon substrates. The effects of the substrate temperature, which is an important parameter in the CAPD nanodiamond film growth process, were structurally and physically investigated. It was found that the films softened with increasing substrate temperature and atomic interdiffusions at interfaces between the films and substrates were activated, which resulted in the formation of SiC at the interfaces. On the other hand, the films fabricated directly on silicon at room temperature were exfoliated due to the poor adhesion and high residual stress. Consequently, intermediate layers that were fabricated at elevated substrate temperatures were employed to improve the adhesion strength of nanodiamond films on silicon substrates. This way, the atomic interdiffusion at the interfaces could be promoted and the residual stress in the films was relieved. In the second stage, the films were fabricated on the intermediate layers at different temperatures. It has shown that the top layer films fabricated at low temperature gained distinctive mechanical and structural properties. By applying this strategy, several micrometres of hard nanodiamond films can be fabricated on Si substrates without easily being peeled off.
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on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition Tsuyoshi Yoshitake, Mohamed Egiza, Kouki Murasawa, Ali M. Ali, Yasuo Fukui, Hidenobu Gonda, and Masatoshi Sakurai 1 Dept. of App. Sci. for Electr. and Mat., Kyushu Univ.,... more
on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition Tsuyoshi Yoshitake, Mohamed Egiza, Kouki Murasawa, Ali M. Ali, Yasuo Fukui, Hidenobu Gonda, and Masatoshi Sakurai 1 Dept. of App. Sci. for Electr. and Mat., Kyushu Univ., Kasuga, Fukuoka 816-8580, Japan. 2 Mechanical Eng. Dept., Kafrelsheikh Univ., Kafrelsheikh, 33516, Egypt 3 OSG Corporation, 2-17 Shirakumo-cho, Toyokawa, Aichi 442-0018, Japan 4 Physics Dept., Faculty of Sci., Al-Azhar University, p.o. 11884, Nasr city, Cairo, Egypt E-mail: tsuyoshi_yoshitake@kyudai.jp
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Diamond/Amorphous Carbon Composite Films Deposited on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition Tsuyoshi Yoshitake, Ali M. Ali, Mohamed Egiza, Kouki Murasawa, Yasuo Fukui, Hidenobu Gonda, and Masatoshi Sakurai 1 Dept.... more
Diamond/Amorphous Carbon Composite Films Deposited on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition Tsuyoshi Yoshitake, Ali M. Ali, Mohamed Egiza, Kouki Murasawa, Yasuo Fukui, Hidenobu Gonda, and Masatoshi Sakurai 1 Dept. of App. Sci. for Electr. and Mat., Kyushu Univ., Kasuga, Fukuoka 816-8580, Japan. 2 Mechanical Eng. Dept., Kafrelsheikh Univ., Kafrelsheikh, 33516, Egypt 3 OSG Corporation, 2-17 Shirakumo-cho, Toyokawa, Aichi 442-0018, Japan 4 Physics Dept., Faculty of Sci., Al-Azhar University, p.o. 11884, Nasr city, Cairo, Egypt E-mail: tsuyoshi_yoshitake@kyudai.jp
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Coaxial arc plasma deposition (CAPD) was employed to manufacture n-type silicon/boron-doped p-type ultrananocrystalline diamond heterojunctions. Measurement and analysis of their dark current density-voltage curve were carried out at room... more
Coaxial arc plasma deposition (CAPD) was employed to manufacture n-type silicon/boron-doped p-type ultrananocrystalline diamond heterojunctions. Measurement and analysis of their dark current density-voltage curve were carried out at room temperature in order to calculate the requisite junction parameters using the Cheung and Norde approaches. For the calculation based on the Cheung approach, the series resistance (Rs), ideality factor (n) and barrier height (Φb) were 4.58 kΩ, 2.82 and 0.75 eV, respectively. The values of Rs and Φb were in agreement with those calculated using the Norde approach. Their characteristics for alternative current impedance at different frequency values were measured and analyzed as a function of the voltage (V) values ranging from 0 V to 0.5 V. Appearance of the real (Z′) and imaginary (Z″) characteristics for all V values presented single semicircles. The centers of the semicircular curves were below the Z′ axis and the diameter of the semicircles decre...
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We report on the structural evolution of diamond-like carbon (DLC) films by the nanosecond pulsed laser annealing process. DLC film is coated on cemented carbide (WC-Co) by cathodic arc ion plating, which is then annealed by ArF laser... more
We report on the structural evolution of diamond-like carbon (DLC) films by the nanosecond pulsed laser annealing process. DLC film is coated on cemented carbide (WC-Co) by cathodic arc ion plating, which is then annealed by ArF laser (193 nm, 20 ns) at different laser flu-ences (0.9-1.7 J/cm 2). Upon laser annealing, Raman spectra divulge higher sp 3 fractions accompanied by a blue shift in the G-peak position, which indicates the changes of sp 2 sites from rings to chains. At higher fluence (>1.2 J/cm 2), the film converts into reduced graphene oxide confirmed by its Raman-active vibrational modes: D, G, and 2D.
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Hard X-ray photoemission spectroscopy (HAXPES) was employed for the structural evaluation of ultrananocrystalline diamond/amorphous carbon (UNCD/a-C) composite films deposited on cemented carbide substrates, at substrate temperatures up... more
Hard X-ray photoemission spectroscopy (HAXPES) was employed for the structural evaluation of ultrananocrystalline diamond/amorphous carbon (UNCD/a-C) composite films deposited on cemented carbide substrates, at substrate temperatures up to 550 • C by coaxial arc plasma deposition. The results were compared with those of soft X-ray photoemission spectroscopy (SXPES). Since nanocrystalline diamond grains are easily destroyed by argon ion bombardment, the structural evaluation of UNCD/a-C films, without the argon ion bombardment, is preferable for precise evaluation. For samples that were preserved in a vacuum box after film preparation, the sp 3 fraction estimated from HAXPES is in good agreement with that of SXPES. The substrate temperature dependencies also exhibited good correspondence with that of hardness and Young's modulus of the films. On the other hand, the sp 3 fraction estimated from SXPES for samples that were not preserved in the vacuum box had an apparent deviation from those of HAXPES. Since it is possible for HAXPES to precisely estimate the sp 3 fraction without the ion bombardment treatment, HAXPES is a feasible method for UNCD/a-C films, comprising nanocrystalline diamond grains.