Effect of oxygen on degradation of defects on ta-C coatings deposited by filtered arc deposition

Murashima, Motoyuki; Deng, Xiaomin; Izuoka, Hiroto; Umehara, Noritsugu; Kousaka, Hiroyuki

doi:10.1016/j.surfcoat.2019.01.115

Cited by 29 publications

(15 citation statements)

References 19 publications

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“…It is well known that the deposition using arc discharge produces highly ionized carbon atoms, resulting in a homogeneous and hard carbonaceous coating. − However, arc discharge also produces micro-/nanoscale carbon clusters, which eventually grow into droplets in/on the coating. Because the droplets cause high wear and degradation of the coating, − lapping and polishing are usually used to remove the droplets. , However, these methods cannot completely remove the droplets. Therefore, droplet-filtering methods during arc deposition have been developed. − The FAD method uses an electromagnetic field to separate ionized carbon atoms from nonionized carbon clusters.…”

Section: Experimental Methodsmentioning

confidence: 99%

Nanotextured Mold Surface with DLC Coating for Reduction in Residual Ceramic Particles

et al. 2021

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In the ceramic industry, ceramic particles remain on a mold surface due to which the mold requires frequent cleaning during press molding, reducing productivity. Surface texturing and tetrahedral amorphous carbon (ta-C) coatings are well-known surface-energy controllable treatments developed for low adhesion, low friction, and high wear resistance. In the present paper, we demonstrate the effect of reducing ceramic residues using nanotexturing, ta-C coatings, and their combination. We compare two surface morphologies (i.e., 770 nm pitch nanotexturing and flat) and five materials (i.e., nonhardened steel, hardened steel, ta-C, and two types of nitrogen-doped ta-C (ta-CNx). Molding test results show that the ta-C coating on flat surfaces with the highest hardness of 30 GPa shows the lowest residual amount of 5.9 μg for Al2O3 ceramic particles. The amount is 82% less than that of the nonhardened steel. The ta-CNx20, made with a nitrogen flow rate of 20 sccm, shows the lowest residual amount of 234 μg for SiO2 ceramic particles, which is 81% less than that of the nontextured ta-CNx20. In conclusion, we provide design guidelines for nanotextured mold surfaces including the texturing pitch should be small enough for ceramic particles; the mold surface should be sufficiently hard; the lower the surface energy per unit area, the less residues of ceramic particles.

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Section: Experimental Methodsmentioning

confidence: 99%

Nanotextured Mold Surface with DLC Coating for Reduction in Residual Ceramic Particles

et al. 2021

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“…In addition, the hydrogen in hydrogenated DLC films causes the hardness to degrade after exposure to elevated temperatures. On the other hand, non-hydrogenated DLC coatings such as tetrahedral amorphous carbon (ta-C) are stable up to 500 °C owing to their high sp 3 phase fraction 5 , 7 , 8 . However, the heat resistance of non-hydrogenated DLC coatings is still too low for moving parts operated in high-temperature environments under external forces.…”

Section: Introductionmentioning

confidence: 99%

Thermal stability of Si/SiC/ta-C composite coatings and improvement of tribological properties through high-temperature annealing

Jang

Kim

et al. 2022

Sci Rep

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We report the structure, mechanical properties, thermal stability, and durability of Si/SiC/ta-C composite (Si–ta-C) coatings fabricated using simultaneous filtered cathodic vacuum arc deposition and direct current unbalanced magnetron sputtering. Si concentration of 1.25–6.04 at.% was achieved by increasing the unbalanced magnetron sputtering power from 25 to 175 W. Si addition provided functionality to the coating, such as heat resistance, while retaining the high hardness of ta-C coatings. The Si–ta-C coatings were stable up to 600 °C regardless of the Si content, while the coating containing 3.85 at.% Si was stable up to 700 °C. The friction behavior and mechanical properties were dependent on the coating film before and after annealing at 100–200 °C; however, annealing at 300–400 °C decreased disk wear and increased counterpart wear due to an increase in film hardness on account of an endothermic reaction that increased the number of Si–C bonds. This indicates that the basic hardness characteristics of the ta-C coating and the high-temperature structural change of the Si–ta-C coating are important for ensuring high-temperature durability. These characteristics were verified through the low coefficient of friction and wear rate of the 1.25 at.% Si–ta-C coating after annealing at 500 °C.

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“…The DLC coatings actively interact with mating materials, resulting in different tribological behavior due to various chemical affinity to carbon atoms [9,10]. Temperature affects both surface morphologies of the DLC coatings [11,12] and their tribological properties [13,14]. Liu et al revealed that a nitrogen contained DLC exhibited excellent tribological characteristics even at lower hardness [15].…”

Section: Introductionmentioning

confidence: 99%

Realization of a Novel Morphing Surface Using Additive Manufacturing and Its Active Control in Friction

Murashima

Imaizumi

Kawaguchi

et al. 2021

Journal of Tribology

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As the need for higher efficiency of engineering components increases, so does the demand for functional surfaces. While various tribosurfaces (e.g., texturing and coatings) have been developed, many researches are aimed at static functionality. On the other hand, due to a wide range of environmental adaptability and active control, active-morphing surfaces can be highly efficient and robust. In this paper, we demonstrate a novel morphing surface and its realization using additive manufacturing (AM). By using a diaphragm structure, morphing performance is achieved even if a hard resin material is used. When air pressure is applied to the backside of the diaphragm, it changes to a convex shape, and vice versa. The concept requires a complex structure for arranging airflow and a solid morphing system. The AM is one great technique to create such complex structure. As a result of actual manufacturing, the created morphing structure realizes a large morphing of 600 µm or more. In addition, the shape changes reversibly depending on the air pressure. The surface also exhibits very interesting tribological characteristics. The surface shows a friction coefficient of 0.5-1.7 with a convexity, and then decreases to about 0.3 with a concavity. A real-contact area measurement reveals that the novel property occurs due to change in the real-contact area depending on surface morphology. In conclusion, the present paper provides a new concept of a novel morphing tribosurface, which selectively performs as a low-friction or break-like surface, created using AM.

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Effect of oxygen on degradation of defects on ta-C coatings deposited by filtered arc deposition

Cited by 29 publications

References 19 publications

Nanotextured Mold Surface with DLC Coating for Reduction in Residual Ceramic Particles

Nanotextured Mold Surface with DLC Coating for Reduction in Residual Ceramic Particles

Thermal stability of Si/SiC/ta-C composite coatings and improvement of tribological properties through high-temperature annealing

Realization of a Novel Morphing Surface Using Additive Manufacturing and Its Active Control in Friction

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