Stress relaxation through thermal gradient structure of tetrahedral amorphous carbon thin film deposited on Ge–Se–Sb-based chalcogenide glass

Kim, Jae-Il; Kim, Jong‐Kuk; Jang, Young-Soo

doi:10.1016/j.diamond.2019.107547

Cited by 12 publications

(6 citation statements)

References 15 publications

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“…Therefore, there is an urgent demand for an AR coating with controllable thickness and RI, along with high conformal coverage, low roughness, and good IR transmittance, that could be readily applied directly onto IR lenses. Zinc sulfide (ZnS) and diamond like carbon (DLC) have been widely utilized as AR coating materials in various forms, such as single-layer, multilayer, and gradient structures. − In general, the optimal thickness of a single layer AR coating for a given incident light wavelength (λ) can be calculated using eq , , d AR = λ 4 × n A R where d AR is optimal thickness and n AR is RI at λ of the AR film. From the RI of pSHVDS 170, the required thickness for AR coating was calculated to be between 1100 to 1170 nm.…”

Section: Resultsmentioning

confidence: 99%

Visible, Mid- and Long-Wave Infrared Transparent Sulfur-Rich Polymer with Enhanced Thermal Stability

Jang,

Choi,

Kang

et al. 2023

Chem. Mater.

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High sulfur content polymers (HSCPs) are regarded as promising materials for infrared (IR) optics, especially the long-wave IR range, due to intrinsic properties of sulfur, but the poor thermal stability of HSCPs limits their reliable utilization in wider IR applications. We herein present a new HSCP, poly(sulfur-co-hexavinyl disiloxane) (pSHVDS), prepared directly from elemental sulfur through sulfur vapor chemical deposition (sCVD). By employing hexavinyl disiloxane (HVDS) comonomer with high functionality (f = 12) and weak absorption in the IR range, despite the poor compatibility between sulfur and HVDS, the sCVD process enables the preparation of highly cross-linked HSCP with 68 wt % sulfur. Furthermore, the combination of high refractive index (RI) of 1.842, high glass transition temperature (T g ) of 151 °C, and high transparency in visible, mid- and long-wave IR range is achieved successfully, which is an unprecedentedly unique property compared to HSCPs reported to date. These favorable properties of pSHVDS render the material ideal for antireflection applications in IR optics, and conformal pSHVDS coatings on germanium IR lenses significantly improved the transmittance in mid- and long-wave IR regions. The developed polymer will lead the new possibility for polymer based optical devices, especially in the IR range.

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Section: Resultsmentioning

confidence: 99%

Visible, Mid- and Long-Wave Infrared Transparent Sulfur-Rich Polymer with Enhanced Thermal Stability

Jang,

Choi,

Kang

et al. 2023

Chem. Mater.

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“…The underlying mechanisms of occurrence as well as the strains and stresses are illustrated stepwise in Figure 8a i-iv . The increased energy of the film-forming particles from the laser arc process [133] bombarding the substrate led to the heating of the coating and the polymer substrate. [134,135] Consequently, thermally induced compressive stresses very likely occurred in the coating when considering the different linear thermal expansion coefficients (TEC) of the DLC coating (α DLC ∼ 1.47 × 10 −6 K −1 [136] ) and the PE substrate (α PE ∼ 2.4-3.6 × 10 −4 K −1 [137] ).…”

Section: Discussion On Appearance and Wear Mechanismsmentioning

confidence: 99%

Wear Mechanism of Superhard Tetrahedral Amorphous Carbon (ta‐C) Coatings for Biomedical Applications

Rothammer

Schwendner

Bartz

et al. 2023

Adv Materials Inter

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Tetrahedral amorphous carbon (ta‐C) coatings have the potential to protect biomedical implants from wear and increase their service life. This study elucidates the biocompatibility, mechanical properties, adhesion, and wear resistance of ta‐C coatings fabricated by physical vapor deposition on cobalt‐chromium‐molybdenum (CoCr) and titanium (Ti64) alloys as well as ultrahigh molecular weight polyethylene (UHMWPE). Satisfactory cytocompatibility is verified using contact angle and surface tension measurements as well as indirect and direct cell testing. Scratch testing demonstrates excellent adhesion to the substrates and as confirmed by nanoindentation, the coatings represent an up to 13‐fold and 182‐fold increase in hardness on the hard and soft materials. In metal pin‐on‐UHMWPE disk sliding experiments under simulated body fluid lubrication, the wear rates of the disk are reduced by 48% (against CoCr) and 73% (against Ti64) while the pin wear rates are reduced by factors of 20 (CoCr) and 116 (Ti64) compared to uncoated pairings. From optical and laser scanning microscopy, Raman measurements, and particle analyses, it is shown that the underlying substrates remain well protected. Nonetheless, focused ion beam scanning electron microscopy revealed coating process‐related and thermally driven subductions as well as tribologically induced near‐surface fatigue, which can potentially constitute critical wear mechanisms.

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“…Reverse polarization curve can used to predict the corrosion developing direction in a longitudinal direction (such as pitting corrosion) or in a horizontal direction (plane corrosion, a uniform corrosion). The smaller potential difference (ΔErev corr) is, the more likely the plane corrosion takes place [12]. For S0, ΔErev corr is 0.122V (the former corrosion potential is -1.457V and reverse corrosion potential is -1.579V), in figure 8.…”

Section: Reverse Potentiodynamic Polarization (Rpdp)mentioning

confidence: 95%

“…The nano amorphous film could be used as corrosion resistant layer should it still work when the nano film is in crystalline form? Generally, amorphous film is weakly bonded to Mg alloy substrate for mismatching in thermal expansion coefficient or lattice [12]. Would crystalline film overcome it?…”

Section: Introductionmentioning

confidence: 99%

Corrosion Evolution of AZ31 Mg Alloy with a Nano Crystallized Film

Jia-cheng

Liu

et al. 2022

J. Phys.: Conf. Ser.

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A comprehensive investigation of nano crystallized GaN film synthesized on AZ31 magnesium alloy substrate using atomic layer deposition (ALD) is presented in this paper. The microstructure and mechanical analysis indicate the nano crystallized film is homogeneous, well-adhesive to Mg alloy substrate. The corrosion experimental results demonstrate that the nanometer crystallized film turns Mg alloy corrosion process from longitudinal/non-uniform to horizontal/uniform corrosion, which is deduced from the facts that a great but less fluctuation surface potential mapping, a smaller ∆Erev, corr and a more uniformed corroded morphology. A higher Ecorr , a smaller icorr and a higher Z also mean the film can yield a prominent amelioration in the Mg alloy corrosion resistance. The work proposes that a uniform coverage even in a nano-magnitude and crystallized form could make corrosion more uniform and later.

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Stress relaxation through thermal gradient structure of tetrahedral amorphous carbon thin film deposited on Ge–Se–Sb-based chalcogenide glass

Cited by 12 publications

References 15 publications

Visible, Mid- and Long-Wave Infrared Transparent Sulfur-Rich Polymer with Enhanced Thermal Stability

Visible, Mid- and Long-Wave Infrared Transparent Sulfur-Rich Polymer with Enhanced Thermal Stability

Wear Mechanism of Superhard Tetrahedral Amorphous Carbon (ta‐C) Coatings for Biomedical Applications

Corrosion Evolution of AZ31 Mg Alloy with a Nano Crystallized Film

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