• 한국표면공학회지
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• 제36권2호
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• pp.116-121
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• 2003

Ti-Si-N coating layers were deposited onto WC-Co substrates by a hybrid system of arc ion plating (AIP) and sputtering techniques. The tribological behaviors of Ti-Si-N coating layers with various Si contents were investigated by the dry sliding wear experiments, which were conducted at three different sliding speeds, 0.1, 0.3, 0.5 m/s, against the steel and alumina balls. In the case of steel ball, the average friction coefficient slightly decreased with increasing the sliding speed regardless of Si content due to adhesive wear behavior between coating layer and steel ball. At constant sliding speed, the average friction coefficient decreased with increase of Si content. On the contrary, in the case of alumina ball, the average friction coefficient increased with increasing the sliding speed regardless of Si content, indicating that the abrasive wear behavior was more dominant when the coating layers slide against alumina ball. Through these experimental results, it was found that the tribological behaviors of Ti-Si-N coating layers were effected by factors such as Si content, sliding speed, and kinds of counterpart materials rather than the hardness of coating layer.

• 한국해양공학회지
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• 제32권6호
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• pp.502-510
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• 2018

In order to accumulate data to lower the friction coefficient of a press mold, tribological tests were performed before and after coating SM45C with a PVC/PO film and plasma coating (CrN, concept). The ultrasonic nanocrystal surface modification (UNSM)-treated material had a nano-size surface texture, high surface hardness, and large and deep compressive residual stress formation. Even when the load was doubled, the small amount of abrasion, small weight of the abrasion, and width and depth of the abrasion did not increase as much as those of untreated materials. A comparison of the weight change before and after the tribological test with the CrN and the concept coating material and that of the untreated material showed that the wear loss of the concept coating material and P-UNSM treated material (that is, the UNSM treated material treated with the concept coating) showed a tendency to decrease by approximately 55-75%. Concept 100N had a lower friction coefficient of about 0.6, and P-UNSM-30-100N showed almost the same curve as concept 100N and had a low coefficient of friction of about 0.6. The concept multilayer coating had a thickness of $5.32{\mu}m$. In the beginning, the coefficient of friction decreased because of the plasma coating, but it started to increase from about 250-300 s. After about 350 s, the coefficient of friction tended to approach the friction coefficient of the SM45C base metal. The SGV-280F film-attached test specimen was slightly pushed back and forth, but the SM45C base material was not exposed due to abrasion. The friction coefficient was 0.22, which was the lowest, and the tribological property was the best in this study.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.161-162
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• 2002

This study concerns the tribological behaviors of ultra-thin DLC coating with 3 nm thickness deposited in a mixed gas of argon + 20 % hydrogen as a function of humidity. Reciprocating wear tests employing a micro wear tester were performed under various normal loads and relative humidity in air environment. The chemical composition of the original and worn surfaces were studied by Auger electron spectroscopy (AES). It showed that the ultra-thin DLC coating exhibited low friction with enough wear stability at low normal load (0.18 N) and its tribological behavior was strongly dependent on the humidity. The sample surfaces before and after the test were examined using atomic force microscopy (AFM). Capillary force and meniscus areas were discussed in order to explain the influence of humidity on the friction force.

• Journal of Mechanical Science and Technology
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• 제16권7호
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• pp.911-918
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• 2002

The tribological performance of A1$_2$O$_3$/NiCr coating deposited on steel (SH45C) was investigated under lubrication. The parameters of sliding wear consist of normal load and coating thickness. Test result showed that there was no evidence of an improved bonding strength in the coating. However, the wear resistance of the A1$_2$O$_3$/NiCr coaling was significantly greater than that of the Al$_2$O$_3$ coating. It was eviclent that the residual stress for the A1$_2$O$_3$coating was higher than that of the A1$_2$O$_3$/NiCr coating from the Scratch test failure of coating. The bond coating played an important role in decreasing the residual stress. Also, it was found that the residual stress had d notable influence on the wear mechanism.

• 한국산학기술학회논문지
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• 제8권3호
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• pp.432-436
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• 2007

자동차 구조용 재료에 대하여 물리적 증착 코팅방법에 의한 트라이볼로지 특성을 연구 하였다. 코팅 재료는 탄화티탄(TiC)과 질화티탄(TiN)이다. 실험은 펠렉스 마찰 마모시험기를 이용하여 하중과 온도에 다양한 조건을 적용하여 마찰과 마모 거동에 대하여 트라이볼로지 특성을 결정하고 평가하였다. 연구결과 코팅하지 않았을 때보다 코팅하였을 때가 윤활 특성이 향상 되었고, 특히 내마모성 및 극압성 그리고 열 안정성이 훌륭하였다.

• Tribology and Lubricants
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• 제14권1호
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• pp.1-6
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• 1998

An experimental study was performed to discover the tribological behaviors of pure tin and zinc coated 52100 bearing steel. Pure tin coatings ranging from 30 nm to 30,000 nm and pure zinc coatings ranging from 500 nm to 52,000 nm were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed for the investigations of the effect of coating thickness on the tribological rolling behavior. Results showed that the existence of optimum film thickness which revealed minimum rolling resistance was discovered for tin and zinc coating. The compatibility of coating material to iron showed no significant effect on the rolling resistance behavior. The hardness of coating material revealed significant influence to the rolling resistance behavior.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.51-58
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• 1997

An experimental study was performed to discover the tribological behaviors of pure tin and zinc coated 52100 bearing steel. Pure tin coatings ranging from 30 nm to 30,000 nm and pure zinc coatings ranging from 500 nm to 52,000 nm were produced by a thermal evaporation coating method. Experiments using a thrust ball bearing-typed rolling test-rig were performed for the investigations of the effect of coating thickness on the tribological rolling behavior. Results showed that the existence of optimum film thickness which revealed minimum rolling resistance was discovered for tin and zinc coating. The compatibility of coating matehal to iron showed no significant effect on the rolling resistance behavior. The hardness of coating material revealed significant influence to the rolling resistance behavior.

• Tribology and Lubricants
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• 제20권5호
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• pp.237-244
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• 2004

Micro/nano tribological characteristics of PTFE coating films were experimentally studied. PTFE (polytetrafluoroethylene) modified polyethylene and low molecular weight PTFE were used as a coating materials. These films were deposited on Si-wafer (100) by IBAD (ion beam assisted deposition) method. The Ar ion beam sputtering was performed to change the surface topography of films using a hollow cathode ion gun under different Ar ion dose conditions in a vacuum chamber. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribotester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. The durability of the films were measured with macro tribotester. Results showed that the PTFE coating surfaces were converted to hydrophobic. The water contact angle of coated surfaces and surface roughness increased with the coating thickness. Adhesion and friction in micro and nano scale were governed by magnitude of normal load in soft material such as PTFE films. As the increase of sputtering time on low molecular weight PTFE films, the surface roughness was increased and nano adhesion and friction were decreased. The nano tribological characteristics of surfaces are mainly improved by chemical modification such as PTFE coating and given a synergy effect by the physical modification such as topographic modification.

• KSTLE International Journal
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• 제6권2호
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• pp.45-50
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• 2005

Plasma ceramic spray that is applied on a machine part under severe work conditions has been investigated for tribological behavior. The application of ceramic coatings by plasma spray has become essential in tribosystems to produce wear resistance and long life in severe conditions. The purpose of this study was to investigate the wear characteristics of $8\%Y_{2}O_3-ZrO_2$ coating, in view of the effect of post-spay heat treatment. The plasma-sprayed $8\%Y_{2}O_3-ZrO_2$ coating was studied to know the relationship between phase transformations and wear behavior related to post-spray heat treatment. Wear test was carried out with ball on disk type on normal loads of 50N,70N and 90N under room temperature. The phase transformation of phase and the value of residual stress were measured by X-ray diffraction method(XRD). Tribological characteristics and wear mechanisms of coatings were observed by SEM. The tribological wear performance was discussed in the focusing of residual stress. Consequently, post-spray heat treatment plays an important role in decreasing residual stress. Residual stress in the coating system has a significant influence on the wear mechanism of coating.

• 정보저장시스템학회논문집
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• 제6권2호
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• pp.68-73
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• 2010

The interest in acquiring high efficiency solar cells has been steadily increasing due to various advantages such as low-cost installation, pollution free and everlasting energy generation. In order to raise the cell efficiency, there has been a lot of effort to develop effective anti-reflection coatings. In this work, the main objective was to investigate the effects of particle size and annealing temperature of silica anti-reflection coatings to maximize the cell efficiency as well as reliability. It was shown that the light transmittance could be increased by a few percent over a certain range of wavelength using the silica coating. Also, the tribological properties of the coating could be improved through the annealing process, which led to better reliability of the coating.