• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.332-338
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• 1999

Surface hardening of plain carbon steel (SM$%C) by Laser are usually much finer and stronger than those of the base metals. The present study was undertaken to investigate the wear resistance and a processing parameters such as, power density, pulse width, defocusing distance, and molten depth for surface modification of plain carbon steel. The wear test was carried out under experimental condition using the wear test device, and in which the annular surfaces of wear test specimens as well as mating specimen of alumina ceramics(Al2O3) was rubbed in dry sliding condition. It is shown that molten depth and width depend on defocusing distance. The wear loss on variation of sliding speed was much in lower speed range below 0.2m/sec and in higher speed range above 0.7m/sec, but wear loss was little in intermediate speed range. It depends on oxidation speed and wear speed.

• Tribology and Lubricants
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• 제15권2호
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• pp.141-149
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• 1999

Fracture, fatigue and wear characteristics of Al-Si alloy used for compressor are experimentally studied. Plane strain fracture toughness test is carried out using three point bending specimen. Fatigue test is performed under constant loading condition and wear test is carried out as a function of sliding velocity and applied load. To obtain the crack propagation characteristics and wear mechanism of Al-Si alloy, fracture and worn surfaces are investigated using SEM. It is verified that fracture and fatigue strength of Al-Si alloy are improved by the fine microstructure of alloy. The wear behavior and specific wear amount of Al-Si alloy are not dependent on the microstructure but on a function of the silicon content. Anodizing on the surface of Al-Si alloy, surface hardness and wear characteristics are improved.

• 열처리공학회지
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• 제13권2호
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• pp.71-84
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• 2000

A study on adhesion and wear resistance of VC(vanadium carbide) coating on die steels, STD11 and STD61, has been carried out. The VC coating on the die steels was made by immersing them in molten borax bath, a kind of TRD(thermo-reactive deposition and diffusion). Adhesion strength and wear resistance were investigated using scratch test, indentation test and plate-disc test(Ogoshi type) respectively. The influence of sliding distance on the amount of wear has been determined and dominant wear mechanisms has been characterized using optical microscopy, scanning electron microscopy and EDS spectroscopy. The critical adhesion strength($L_c$) between VC coating layer and substrate(STD11) was increased to 60N($L_c$) in the scratch test. In the case of STD61, the strength increased to 24N. The wear resistance of VC coated die steels was excellent because the diffusion layer formed just below the coating layer. The dominant wear mechanism was identified as adhesive wear for VC coating die steels which were worn by combination of cracking and plucking of VC fragments and disc.

• 패션비즈니스
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• 제11권3호
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• pp.15-34
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• 2007

This study was designed to collect a precise information concerning to the preference and evaluations after usage of pregnant Korean woman for the maternity wear bysurvey and wear tests. Through the survey, 212 respondents were asked to answer what type of maternity wear they prefer and what requirements for maternity wear design are important. According to the results of survey, the mostly preferred maternity wear items were pants and one-piece dress. Korean customers for maternity wear usually pay more for the one-piece dress than other items and they also usually put on medium price pants and low-price blouse. Concerning to the purchase criteria, it may be said that design and movability, fit factors are the buying decision criteria of great weight for Korean pregnant women. Special function most desired was thermal insulation, followed by buffer action, electromagnetic shield and quickly water-absorbent and dry property. Preferred maternity wear design details were flat collar, slightly fitted waist and empire style, gather skirt, rubber band waist. Wear test was performed for two kinds of blouse (BL) and one-piece dress (OP), and threekinds of pants (PT), which have different design details respectively. According to the wear test for ready-to-wear maternity garments, the garment which considers well the characteristics of Korean pregnant women body shape earned much higher score no matter of brands or prices. Generally, high-priced national brands received an excellent evaluation in design aspect, but not satisfied with comfort to move.

• Tribology and Lubricants
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• 제39권6호
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• pp.256-261
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• 2023

This study is conducted to evaluate the durability of superhydrophobic surfaces, with a focus on two aspects: contact angle measurement and self-cleaning-performance analysis. Superhydrophobic copper and aluminum surfaces are fabricated using the immersion method and subjected to a rolling wear test, in which a 2 kg weight is placed on a rolling tester, under loaded conditions. To evaluate their durability, the contact angles of the specimens are measured for each cycle. In addition, the surface deformation of the specimens before and after the test is analyzed through SEM imaging and EDS mapping. The degradation of the self-cleaning performance is evaluated before and after the wear test. The results show that superhydrophobic aluminum is approximately 4.5 times more durable than superhydrophobic copper; the copper and aluminum specimens could endure 21,000 and 4,300 cycles of wear, respectively. The results of the self-cleaning test demonstrate that superhydrophobic aluminum is superior to superhydrophobic copper. After the wear test, the self-cleaning rates of the copper and aluminum specimens decrease to 72.7% and 83.4%, respectively. The relatively minor decrease in the self-cleaning rate of the aluminum specimen, despite the large number of wear cycles, confirms that the superhydrophobic aluminum specimen is more durable than its copper counterpart. This study is expected to aid in evaluating the durability of superhydrophobic surfaces in the future owing to the advantage of performing wear tests on superhydrophobic surfaces without damaging the surface coating.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.304-309
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• 2002

Fretting wear test in room temperature water was performed to evaluate the wear coefficient of Inconel 600,690 (Pressurized Water Reactor, PWR) and Alloy 800 (CANadian DeuteriumUranium, CANDU) steam generator (SG) tubes against ferritic and martensitic stainless steels. The main focus is to compare the wear behaviors between Alloy 800 and Inconel alloys. Test conditions are $10{\sim}30N$ of normal load, $200{\sim}450{\mu}m$ of sliding amplitude and 30Hz of frequency. The result indicated that the wear rate of Alloy 800 was higher than those of Inconel 690 at various test condition such as normal loads, sliding amplitudes etc. From the results of SEM observation, there was little evidence of plastic deformation layer that were dominantly formed on the worn surfaces of Inconel 690. Also, wear particles in Alloy 800 were released from contacting asperities deformed by severe plastic flow during fretting wear. Main cause of wear rate between Alloy 800 and Inconel 690 may be due to the difference of hardness between martensitic and ferritic stainless steel. The wear rate and wear mechanism of two tubes in room temperature water are discussed.

• 소성∙가공
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• 제31권1호
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• pp.11-16
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• 2022

In this paper, wear characteristics of PVD coatings were compared on the die surface for cold stamping of MART1470 steel sheet with the finite element analysis and the pin-on-disc wear test. Three types of PVD coatings (CrN, TiAlCrN, and MoS2TiCr(W)N) were considered for the tool surface made of STD11 material. The stamping process of an auto-body part was analyzed with the finite element method. Ranges of process variables for the wear test such as contact pressure, relative speed, and sliding distance were predicted from analysis results. In order to quantitatively analyze wear characteristics of each coating, the amount of wear was measured and compared according to process variables with the pin-on-disc wear test. The influence of each process variable was investigated and the wear characteristics of the three coating layers were quantitatively compared. It was confirmed that the wear characteristics of MoS₂TiCr(W)N coating were better than those of CrN and TiAlCrN. It was noted that the proposed prediction approach could predict and respond to the wear phenomenon occurring in the stamping process.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.141-142
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• 2002

In this paper, we propose a slurry jet (water containing $1\;{\mu}m$ alumina particles) impact test in order to quickly evaluate the wear properties of physical vapor deposited (PVD) coatings on commercial cutting tools. Linear wear was obtained for bothe coating and substrate material, and the penetration through the coating into the substrate was signified by a sharp increase in slope of the wear versus time curve. The PVD coatings deposited on the tools showed the same wear rates as those on reference plate specimens produced by the same coating methods. We conclude that our proposed evaluation technique for coatings is considerably useful as a screening test when evaluating coated tools like twist drills, taps, end mills, gear hobs, etc.

• Tribology and Lubricants
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• 제15권1호
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• pp.83-89
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• 1999

The fretting wear behaviour of Zircaloy-4 tube used as the fuel rod cladding in PWR nuclear power plants has been investigated at the different test environment, in light water and in air as a function of slip amplitude, normal load, test duration and frequency. Zircaloy-4 tubes were used for both of oscillating and stationary specimens. A fretting wear tester was designed to be suitable for this fretting test. The wear volume and specific wear rate of Zircaloy-4 tube in water was greater than those in air under various slip amplitude. Delaminates and surface cracks were observed at low slip amplitude and high load of fretting test in water, but the traces of adhesion and plowing were observed at and above 200 Um. The water accelerates the wear of Zircaloy-4 tube at lower slip amplitude in fretting.

• 한국염색가공학회지
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• 제23권1호
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• pp.60-68
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• 2011

The effect of compression wear for sport performance and muscle function was investigated based on the physiological test and electromyograph(EMG). The EMG test was used to study muscle activity after fitting the compression wear during exercise. It showed slight difference between men and women testee groups in the results of anaerobic, aerobic, fatigue, and EMG test due to muscle content in the body. In addition, the exercise performance was increased to some extent even the muscle activity was decreased. It is estimated that the compression effect to muscle by the compression wear decreased the muscle vibration and improved blood circulation which helped the entire sport performance. However, it is necessary to study the effect of compression wear in long-term wearing in the future study.