• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.82-86
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• 1996

This study was performed to elucidate the effect of degree of substitution and degree of polymerization of CMC on the rheological characteristics of coating color which is consisted of calcium carbonate as pigment. The results were as follows: 1. It appeared that DP of CMC rather DS has an effect on the low shear viscosity of coating color. 2. According as shear rate increased, the effect of DP and DS on high shear viscosity of coating color decreased. 3. According to increasing DS and DP, the water retention of coating color increased.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.130-137
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• 2017

PURPOSE. The purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements. MATERIALS AND METHODS. A total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength (P<.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used. RESULTS. Groups treated with the nano-structured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating. CONCLUSION. Nano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.

• Journal of the Korean institute of surface engineering
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• v.52 no.1
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• pp.6-15
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• 2019

Metal-halide perovskite (MHP) solar cell is a promising candidate for next-generation flexible devices and the BIPV (Building-integrated photovoltaics) because it can exhibit high power conversion efficiencies over 23%, good bendability and low processing cost. However, MHP solar cells are commonly fabricated by the spin coating that is not a reliable method to produce large-scale commercial solar cells. A shear coating can be one of the potential candidates for the large-scale deposition method of MHP films. In this work, the influences of the process parameters such as solvents of precursor solution, substrate temperature, concentrations of precursor solution, and annealing time on the thin film growth of MHP were investigated for the shear coating process. This study presents the possibility of the shear coating process for large-scaled perovskite film fabrication and reveals the role of process condition in the thin film growth of perovskites.

• Journal of Welding and Joining
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• v.25 no.4
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• pp.65-71
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• 2007

Laser weldability of the aluminized steel for the full penetration welding will be described in this paper. We focused on the effect of Al coating conditions on weld strength. For these objectives, aluminized steel sheets that have various thickness and coating weight were prepared for laser welding. And then, tensile-shear and hardness test were carried out. At the same time, Al contents in weld after laser welding were analyzed and their correlations with mechanical properties were investigated. Besides, as removing partially coating layer, weldability has been investigated according to the position of coating layer. As a result of this study, tensile-shear strength was decreased with increasing Al contents in weld, and Al of coating layer caused grain growth.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.2 s.146
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• pp.268-274
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• 2006

Analysis has been made of the anti-corrosive property of organic coating under the shear stress of the flow by means of AC impedance method. Marine anti-corrosive painted panels were placed in the water channel with varying flow rate, thereby experiencing varying flow shear stress on the surfaces. The velocities of the salt water were ranged from 1.48 to 5.2 m/s and the coating thickness of from $70{\mu}m\;to\;140{\mu}m$. For all coating thicknesses investigated, the poorer anti-corrosive property and the lower adhesion strength have been found for the higher shear stress. It has been found that the shear stress accelerates the aging of organic marine coatings.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.3
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• pp.121-127
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• 2011

This study used two types of rheology modifiers including an alkali-swellable emulsion (ASE) and an surface-adhesion emulsion (SAE) to elucidate their effects on high shear viscosity and dynamic penetration behavior among the flow properties of high solids coating. Since rheology under high shear and dynamic penetration behavior significantly affect the quality of coated paper in case of high solids coating, it is very important to examine the variations in rheology of high solids coating color by rheology modifier. It was found that the high solids coating color prepared with the SAE type showed superior dynamic penetration behavior and high shear viscosity than that with the ASE type rheology modifier.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.354-363
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• 2016

Purpose: The aim of this study was to investigate whether the application of nano-structured alumina coating to the surface of Y-TZP could enhance the bond strength with resin cement. Materials and methods: A total of 80 zirconia plates were prepared and divided into four groups. : 1) airborne particle abrasion treatment (A) : 2) Rocatec treatment after airborne particle abrasion (R) : 3) nano-structured alumina coating treatment after polishing (PC) and 4) nano-structured alumina coating after airborne particle abrasion (AC). Alumina coating was formed by the hydrolysis of aluminium nitride (AlN) powder and heat treatment at $900^{\circ}C$. Coating patterns were observed with FE-SEM. Resin block was bonded to treated zirconia ceramics using resin cement. The shear bond strengths were measured before and after thermocycling. Results: The FE-SEM images show a dense and uniform nano-structured alumina coating structure, which enhances shear bond strength by increasing micro mechanical interlocking to resin cement. PC and AC groups showed higher shear bond strengths than A and R groups before and after thermocycling. A and R groups displayed significant drops in shear bond strength after thermocycling. However, PC and AC groups did not show any meaningful decreases in shear bond strength after thermocycling. Conclusion: Treatment of Y-TZP ceramics with nano-structured alumina coating could significantly increase their shear bond strength.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.238-243
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• 2007

This paper is designed to estimate the adhesion strength of coating layer on galvannealed steel sheet using lap shear test. The single lap shear test is the most commonly used standard test for determining the strength of medium-strength and high strength bonds. The bond strength of bonded single lap joints on subjecting the substrates to loads is determined by lap shear forces in the direction of the bonded joint. In this study, specimen for adhesion strength test was made to attach coated sheet to cold rolled sheet and were heated in temperature of 180 for 20minutes. After test, detached parts of coatings on coated sheet were observed using SEM and EDX to identify substrate and complete detachment. The tested results showed that adhesive strength of coating is unrelated to anisotropy of sheet and is difficult to be extracted using conventional theory because of fine cracks of coating layers which were created during annealing process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.1 s.24
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• pp.9-14
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• 2006

Analysis has been made of the anti-corrosive property of organic coating under the shear stress of the flow by means of AC impedance method. Marine anti-corrosive painted panels were placed in the water channel with varying flow rate, thereby experiencing varying flow shear stress on the surfaces. The velocities of the salt water were ranged from 1.48 to 5.2 m/s and the coating thickness of from $70{\mu}m\;to\;140{\mu}m$. For all coating thicknesses investigated, the poorer anti-corrosive property and the lower adhesion strength have been found for the higher shear stress. It has been found that the shear stress accelerates the aging of organic marine coatings.

• Journal of the Korean institute of surface engineering
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• v.53 no.4
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• pp.182-189
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• 2020

Indium tin oxide (ITO) used a transparent electrode of a photoelectric device has a low sheet resistance and a high transmittance. However, ITO is disadvantageous in that the process cost is expensive, and the process time is long. Silver nanowires (AgNWs) transparent electrodes are based on a low cost solution process. In addition, it has attracted attention as a next-generation transparent electrode material that replaces ITO because it has similar electrical and optical characteristic to ITO, it is noted as a. AgNW thin films are mainly produced by spin-coating. However, the spin-coating process has a disadvantage of high material loss. In this study, the material loss was reduced by using about 2~10 ㎕ of AgNW solution on a (25 × 25) ㎟ substrate using the shear-coating method. It was also possible to align AgNWs in the drag direction by dragging the meniscus of the solution. The electro-optical properties of the AgNW thin film were adjusted by changing the experimental parameters that the amount of AgNWs suspension, the gap between the substrate and the blade, and the coating speed. As a result, AgNW thin films with a transmittance of 90.7 % at a wavelength of 550 nm and a sheet resistance of 15 Ω/□ was deposited and exhibited similar properties to similar AgNW transparent electrodes studied by other researchers.