• 한국표면공학회지
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• 제43권6호
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• pp.283-288
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• 2010

Ni-$TiO_2$ nano composite coatings were fabricated using pulse current electrodeposition technique at 100 Hz pulse frequency with a constant 50% pulse duty cycles and reference was taken with respect to the direct current (dc) electrodeposition. The properties of the composite coatings were investigated by using SEM, XRD, Wear test and Vicker's microhardness test. Pulse electrodeposited composite has exhibited enhancement of (111), (220), and (311) diffraction lines with an attenuation of (200) line. The results demonstrated that the microhardness of composite coatings under pulse condition was significantly improved than that of pure nickel coating as well as dc electrodeposited Ni-$TiO_2$ composite coatings. Wear tracks have shown the less plastic deformation in pulse plated composite. Coefficient of friction was also found to be lower in pulse plated composite coatings as compared to dc plated composite coatings.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.153-153
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• 2011

Ni $TiO_2$ nano composite coatings were fabricated by using pulse current electrodeposition technique at 100 Hz pulse frequency with a constant 50% pulse duty cycles and reference was taken with respect to the direct current electrodeposition. The properties of the composite coatings were investigated by using SEM, XRD, Wear test and Vicker's microhardness test. XRD patterns of pulse deposited composite coatings were found to be changed from preferred (100) orientation to the random mixed orientations. The results demonstrated that the Vickers microhardness of composite coatings under pulse condition was significantly improved than that of pure nickel coating as well as direct current electrodeposited Ni-$TiO_2$ composite coatings. Wear tracks have shown the less plastic deformation at pulse condition with reduced coefficient of friction. Nickel matrix grain size was also found to be lower in pulse plated composite coatings as compared to direct current electrodeposited composite coatings.

• 한국표면공학회지
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• 제43권5호
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• pp.224-229
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• 2010

$Ni-Si_3N_4$ nano-composite coatings were prepared by pulse current (PC) electrodeposition and direct current (DC) electrodeposition techniques. The micro-structure of the coatings was characterized by scanning electron microscopy (SEM), vickers microhardness, X-Ray Diffraction (XRD) and wear-friction tests. The results showed that the micro-structure and wear performance of the coatings were affected by the electrodeposition techniques. Pulse current electrodeposited $Ni-Si_3N_4$ composite coatings exhibited higher microhardness, smooth surface, and better wear resistance properties as compared to coatings prepared under DC condition. The $Ni-Si_3N_4$ composite coatings prepared at 50 Hz pulse frequency with 10% duty cycles has shown higher codeposition of nano-particles. Consequently, increased microhardness and less plastic deformations occurred in coatings during sliding wear test. The XRD patterns revealed that the increased pulse frequencies changed the preferred (100) nickel crystallite orientations into mixed (111) and (100) orientations.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.58-58
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• 2011

Nickel-ceramics nanocomposite coatings can be applied as the wear resistance coating, corrosion protection of underlying materials, and decorative coatings. Hence, Nickel based nanocomposite coatings, especially Ni-SiC, have been extensively studied in recent years. However, more often agglomeration problem of the nanoparticles in the nickel matrix can cause deterioration of the mechanical properties rather than improvement. The homogeneous distribution of the nanoparticles in the matrix coating is still being challenging. In this experiment, electrochemical deposition of Ni-SiC composite coating was done in presence of ultrasound. The effects of different ultrasonic powers and frequencies on the nanoparticle dispersion were studied. The electrodeposition was carried out in nickel sulfamate bath by applying pulse current technique. Compared to the conventional mechanical stirring technique to prevent nanoparticles agglomeration and sedimentation during composite electrodeposition, the aid of ultrasonic dispersion along with mechanical stirring has been found to be more effective not only for the nanoparticles dispersion, but also for the mechanical properties of the electrodeposited coatings. Nanoparticles were found to be distributed homogeneously with reduced agglomeration. The microstructure of the composite coating has also been changed, allowing some random orientations of the nickel crystallite grain growths, smooth surface, and finer grains. As a consequence, better mechanical properties of the composites were observed.

• 전기화학회지
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• 제9권2호
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• pp.59-63
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• 2006

전해코팅 법과 dip-coating 법을 이용해 산화주석(IV)을 티타늄 지지체에 코팅하여, 코팅 방법에 따른 코팅 전극의 물성과 전기화학적 특성에 대해여 연구하였다. HCl 로 전극 에칭 후, nitrate 용액에 $SnCl_2{\cdot}2H_2O$을 용해시켜 pulse technique를 이용하여 전해코팅 하였으며, dip-coating 법 또한 $SnCl_2{\cdot}2H_2O$를 사용하여 1:1V% HCl 용액에 용해시켜 코팅 소결 후 산화주석(IV)코팅 전극을 제작하였다. 두 가지 코팅 방법을 통해 제작된 산화주석(IV)코팅 전극은 전극의 물성을 비교하기 위해 x-ray diffraction (XRD), scanning election microscopy (SEM)를 관찰해보았고, 전기화학적 특성을 평가하기 위해 cyclic voltammetry (CV)를 측정하여 전위창을 비교해 보았다.