• Journal of Korean Vacuum Science & Technology
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• v.2 no.2
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• pp.101-106
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• 1998

The poor wear and scratch properties of polycarbonate have limited its application in many fields. In order to improve the wear and scratch properties of polycarbonate we have deposited diamond like carbon (DLC) coatings. The diamond like carbon coatings were made using a high frequency ion beam gun by introducing H2 and CH4 gases. The coatings were characterized with Raman spectroscopy, scanning electron microscope, ellipsometer, microscratch tester and hazemeter. Polymeric hard coating was applied onto the polycarbonate substrate before depositing a DLC coating to investigate the effect of interlayer on the system's failure mode.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.472-483
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• 1999

Hard coatings playa continuously increasing role in the field of tribology as well as for decorative applications. In both areas they are often also exposed to corrosive media. While especially hard nitride coatings show a high corrosion resistance for themselves, hard $coating_strate systems may suffer from a severe corrosion attack due to the defects in the coating structure (pores, pinholes) resulting from the PVD-typical film morphology. While a huge number of investigations cover the tribological properties, only limited studies deal with the corrosion behavjour of coating substrate systems and attempts are made to improve their corrosion resistance. The present paper shortly describes the corrosion mechanisms and repots characteristic examples of the system behaviour. Special emphasis is laid on recent investigations to improve the corrosion resistance by alloying, interlayers or multilayered coating structures.es.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.523-527
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• 2013

Ti-based coatings following laser ablation were studied to compare degradation behaviors by thermomechanical stress. TiN, TiCN, and TiAlN coatings were degraded by a Nd:YAG pulsed laser with an increase in the laser pulses. A decrease in the hardness was identified as the pulses increased, and the hardness levels were in the order of TiAlN > TiCN > TiN. The TiN showed cracks on the surface, and cracks with pores formed along the cracks were observed in the TiCN. The dominant degradation behavior of the TiAlN was surface pore formation. EDS results revealed that diffusion of substrate atoms to the coating surface occurred in the TiN. Delamination occurred in the TiN and TiCN, while the TiAlN which has higher thermal stability than the TiN and TiCN maintained adhesion to the substrate. It was considered that the decrease in the hardness of the Ti-based hard coatings is attributed to surface cracking and the diffusion of substrate atoms.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.51-52
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• 2002

We report results on microtribological studies of chemically grafted nanoscale polymer layers of different architecture with thickness below 30 nm. We have fabricated the molecular lubrication coatings from elastomeric tri-block copolymers and tested two different designs of corresponding nanocomposite coatings. We observed a significant reduction of friction forces and an increase of the wear stability when a minute amount of oil was trapped within the grafted polymer layer. These polymer gel layers exhibited a very steady friction response and a small value of the coefficient of friction as compared to the initial polymer coating. A polymer 'triplex' coating has been formed by a multiple grafting technique. The unique design of this layer Includes a hard-soft-hard architecture with a compliant rubber interlayer mediating localized stresses transferred through the topmost hard layer. This architecture provides a non-linear mechanical response under a normal compression stress and allows additional dissipation of mechanical energy via the elastic rubber interlayer.

• Journal of Adhesion and Interface
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• v.9 no.3
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• pp.1-6
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• 2008

Hard coatings were deposited on a polycarbonate plate as potential substitutes for glass in cars. In this research the copolymers of p-polyphenylene (PPH) and m-phenylene (MPH) were synthesized, and using these copolymers the coatings were conducted on a polycarbonate plate. The hardness of the coating surface was affected with the mole ratio of PPH and MPH in the copolymer. When the mole ratio of PPH : MPH in the copolymer was 20 : 80, the coating showed 2H class of pencil hardness and also showed the best abrasion resistance.

• Polymer(Korea)
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• v.32 no.5
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• pp.427-432
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• 2008

Hard coatings were deposited on a polycarbonate plate as potential substitutes for glass in cars. In this research polyphenylene derivatives were synthesized and the coatings were conducted on a polycarbonate plate. Poly(benzoylphenylene) and its phenylene copolymers were synthesized. Using poly (benzoylphenylene), the coating showed 1H class of pencil hardness. And using its copolymers, the coating showed 2H class of pencil hardness. The copolymer also showed the better abrasion resistance than homopoly (benzoylphenylene).

• Corrosion Science and Technology
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• v.5 no.1
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• pp.15-22
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• 2006

The introduction of two-grid inside a conventional process system produces a reactive coating deposition and increases metal ion ratio in the plasma, resulting in denser and smoother films. The corrosion behaviors of TiN coatings were investigated by electrochemical methods, such as potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) in deaerated 3.5% NaCl solution. Electrochemical tests were used to evaluate the effect of microstructure on the corrosion behavior of TiN coatings exposed to a corrosive environment. The crystal structure of the coatings was examined by X-ray diffractometry (XRD) and the microstructure of the coatings was investigated by scanning electron microscopy (SEM) and transmission electron spectroscopy (TEM). In the potentiodynamic polarization test and EIS measurement, the corrosion current density of TiN deposited by two grid-attached magnetron sputtering was lower than TiN deposited by conventional magnetron type and also presented higher Rct values during 240 h immersion time. It is attributed to the formation of a dense microstructure, which promotes the compactness of coatings and yields lower porosity.

• Journal of the Korean institute of surface engineering
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• v.53 no.6
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• pp.360-368
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• 2020

Wear resistance of cutting tools is one of the most important requirements in terms of the durability of cutting tool itself as well as the machining accuracy of the workpiece. Generally, tungsten carbide ball end mills have been processed with hard coatings for high durability and wear resistance such as diamond coating and tetrahedral amorphous carbon(ta-C) coating. In this study, we developed multilayer ta-C coatings whose wear resistance is comparable to that of diamond coating. First, we prepared single layer ta-C coatings according to the substrate bias voltage and Ar gas flow, and the surface microstructure, raman characteristics, hardness and wear characteristics were evaluated. Then, considering the hardness and wear resistance of the single layer ta-C, we fabricated multilayer coatings consisting of hard and soft layers. As a result, it was confirmed that the wear resistance of the multilayer ta-C coating with hardness of 51 GPa, and elastic recovery rate of 85% improved to 97% compared to that of the diamond coated ball end mill.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.170-176
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• 2006

The hard coatings on the polycarbonate plate were performed with the object of substitution the glass in the car to the polycarbonate plate. In this research, (3-glycidoxypropyl)trimethoxysilane (GPTMS), (3-aminopropyl)triethoxysilane (APS), and diethylenetriamine (DETA) were used to prepare the coatings by a sol-gel process. The optimum conditions and formulation to achiere the excellent physical properties of the coating were determined. In the case of using GPTMS and DETA, the smooth coating which had the 2 H class in pencil hardness was formed. In the case of using GPTMS and APS, the coating which had the 2 H class in pencil hardness was also formed. And the coatings with GPTMS and DETA showed an excellent abrasion resistant.

• Journal of the Korean institute of surface engineering
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• v.54 no.3
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• pp.139-143
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• 2021

Cr-Al-N coatings were deposited onto WC-Co substrates using a cathodic arc evaporation (CAE) system. CAE technique is recognized to be a very useful process for hard coatings because it has many advantages such as high packing density and good adhesion to metallic substrates. In this study, the influence of deposition temperature as a key process parameter on film growth behavior and mechanical properties of Cr-Al-N coatings were systematically investigated and correlated with microstructural changes. From various analyses, the Cr-Al-N coatings prepared at deposition temperature of 450℃ in the CAE process showed excellent mechanical properties with higher deposition rate. The Cr-Al-N coatings with deposition temperature around 450℃ exhibited the highest hardness of about 35 GPa and elastic modulus of 442 GPa. The resistance to elastic strain to failure (H/E ratio) and the index of plastic deformation (H³/E² ratio) were also good values of 0.079 and 0.221 GPa, respectively, at the deposition temperature of 450℃. Based on the XRD, SEM and TEM analyses, the Cr-Al-N coatings exhibited a dense columnar structure with f.c.c. (Cr,Al)N multi-oriented phases in which crystallites showed irregular shapes (50~100nm in size) with many edge dislocations and lattice mismatches.