• 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.

• 패션비즈니스
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• 제19권2호
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• pp.69-84
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• 2015

The objective of this study is to investigate the intention to adopt smart wear, based on extended UTAUT model. We examined the effects of performance expectancy (PE), effort expectancy (EE), hedonic motivation (HE), social influence (SI), facilitating conditions (FC), and price value (PV) on the intended adoption of smart watch and smart shoes, respectively. In addition, moderating effects of gender, age, and innovation resistance were examined. An online survey was conducted, comprised of 2030 consumers who were aware of smart watch or smart shoes. In total, 393 responses were analyzed. About 50.4% were male, and 44.8% were in their 20's. An exploratory factor analysis generated five factors - PE & HM, EE, SI, FC, and PV- which were employed as independent variables in the multiple regression models. PE & HM, PV, and SI influenced on the intention to use both smart devices. FC showed the significant effect only on the intention to adopt the smart watch. In terms of gender differences, SI and PV were the important predictors of the intention to adopt the smart watch in the female group only. With respect to age difference, SI was very effective in explaining the intention of individuals in their 30's to adopt smart wear. Among the low innovation resistance group, SI was significant predictor, while PE & HE and PV were significant among the high resistance group. The findings provide useful information about the possibility of the adoption of smart wear, and new insight into market segmentation.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.267-268
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• 2002

Engine testing of new low-sulfur, low-phosphorus anti wear components is expensive and time consuming so bench testing of potential candidates is highly desirable as a first step evaluation. Electrical contact resistance (ECR) has been shown to be a convenient method to assess antiwear film formation in a ball-on-flat bench wear test. Correlation of the bench test to fired engines was demonstrated for lubricants varying only in the type of detergent. Previous papers have examined film formation by one and two component formulations of zinc dialkyldithiophosphate (ZnDTP) and detergents. In this study, the ECR technique is systematically extended to formulations including ZnDTP, detergent, and dispersant. Both type and level of components are considered and the implications for engine performance are discussed.

• Tribology and Lubricants
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• 제40권3호
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• pp.84-90
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• 2024

This study investigates the effect of the surface microstructure on the tribological characteristics of glass substrates. Chemical etching using hydrofluoric acid and ammonium hydrogen fluoride was employed to create controlled asperity structures on glass surfaces. By varying the etching time from 10 to 50 min, different surface morphologies were obtained and characterized using optical microscopy, surface roughness measurements, and water contact angle analysis. Friction tests were performed using a stainless steel ball as the counter surface to evaluate the tribological behavior of the etched specimens. The results showed that the specimen etched for 20 min exhibited the lowest and most stable friction coefficient, which was attributed to the formation of a uniform and dense asperity structure that effectively reduced the stress concentration and wear at the contact interface. In contrast, specimens etched for shorter (10 min) or longer (30-50 min) durations displayed higher friction coefficients and accelerated wear owing to nonuniform asperity structures that led to local stress concentration. Optical microscopy of the wear tracks further confirmed the superior wear resistance of the 20-minute etched specimen. These findings highlight the importance of optimizing the etching process parameters to achieve the desired surface morphology for enhanced tribological performance, suggesting the potential of chemical etching as a surface modification technique for various materials in tribological applications.

• 한국분말재료학회지
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• 제15권5호
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• pp.359-364
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• 2008

To satisfy the demand of higher cutting performance, mechanical properties with tungsten carbide (WC-Co) tool materials were investigated. Hardness and transverse rupture strength with WC grain size, Co content and density were measured. Compared to H, K, and S manufacture maker as tungsten carbide (WC-Co) tool materials were used for high-speed machining of end-milling operation. The three tungsten carbide (WC-Co) tool materials were evaluated by cutting of STD 11 cold-worked die steel (HRC25) under high-speed cutting condition. Also, tool life was obtained from measuring flank wear by CCD wear measuring system. Tool dynamometer was used to measure cutting force. The cutting force and tool wear are discussed along with tool material characteristics. Consequently, the end-mill of K, H manufacture maker showed higher wear-resistance due to its higher hardness, while the S maker endmill tool showed better performance for high metal removal.

• 한국정밀공학회지
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• 제17권5호
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• pp.186-194
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• 2000

The purpose of this study is to investigate the difference in cutting characteristics of cermet, carbide and coated carbide tools in the similar application range via turning test of various conditions. The cermet and carbide tools in the range of ISO P10 grade were developed using optimum compositions with a view to obtaining a high toughness and hardness by PM process. First mechanical properties were characterized on these tools. Experimental results of wear behaviour and resistance to fracturing were presented and discussed in the turning of gray cast iron and alloy steels by cermet, carbide and coated carbide tools. The coated carbide tool shows similar cutting performance compared to the cermet, while the cermet has better combination of wear resistance and toughness of high speed (V=500m/min) cutting in comparison with carbide and coated carbide tools, and also shows a potentiality for cast iron cutting. Fe adhesive behaviour on the tools and surface roughness of workpieces were explained by chemical affinity between tools and workpieces.

• 한국기계가공학회지
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• 제21권1호
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• pp.81-89
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• 2022

It is necessary to increase the surface hardness and improve the wear resistance and peeling resistance through the surface treatment and performance evaluation of the mold steel. As a result of vacuum heat treatment analysis, residual austenite measurement and surface treatment wear test, retained austenite should be removed by sub-zero treatment, and retained austenite was completely removed by treatment at -196℃. The TiMon film coated on the sub-zero treated STD11 specimen showed the lowest coefficient of friction.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2153-2162
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• 2011

The goal of this Paper is to reduce rail's wear in curved track by applying an additional surface layer material(High hardness and High resistance capacity of wear) on the top of the railhead. In order to evaluate appropriation of a coating material, experimental tests such as the varieties of fundamental properties tests (hardening, wear, tensile, and bending) and RCF(rolling contact fatigue)test were performed to establish fatigue wear and damage mechanism. As a result, wear performance of coating rail is better than heated rail about 6times and normal rail about 8~9times.

• 한국주조공학회지
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• 제14권1호
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• pp.75-81
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• 1994

It is very important to obtain high performance ductile iron by addition a small amount of alloying elements. In this study, to improve the characteristics of small piston ring casted from ductile iron melt a small amount of boron($0{\sim}0.008wt.%$) that is powerful carbide stabilizer was added in ductile iron, and inspected it`s effects on the microstructure, wear resistance, machinability and mechanical properties. The results obtained from this study are as follows. 1. As the amount of boron increased to 0.04wt.%, the machinability of ductile iron is increased, and if the amount is in excess of 0.04wt.% the machinability is decreased conversely. 2. The wear resistance of ductile iron is improved by boron addition. 3. The recommended ladle addition of boron amount ranges from 0.04wt.% to 0.06wt.% for the use of small piston ring.

• Elastomers and Composites
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• 제44권4호
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• pp.401-407
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• 2009

용액중합 스티렌-부타디엔 고무 컴파운드 가교체의 균열저항성 및 마모특성에 미치는 공정오일의 영향을 조사하기 위해 방향족 고리화합물(PCA) 성분을 다량 함유하고 있는 방향족 오일과 저 PCA 오일을 선택하였다. 인장강도 및 인열강도 결과에 의하면 방향족 오일함유 컴파운드가 저 PCA 오일함유 컴파운드에 비해 우수한 물성을 나타내었다. 또한 방향족 오일함유 컴파운드가 균열저항성이 월등히 우수하였고, 특히 인열에너지가 낮은 범위에서 더 우수한 결과를 나타내었다. 마모저항특성은 마찰에너지가 낮은 범위에서는 방향족 오일함유 컴파운드가 우수한 결과를 나타낸 반면, 높은 마찰에너지 범위에서는 저 PCA 오일 함유 컴파운드가 오히려 높은 저항성을 나타내었다.