• Journal of the Korean Ceramic Society
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• v.33 no.3
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• pp.277-284
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• 1996

The water test results indicated that the impurities had detrimetal effect on the wear resistance of silicon nitride and the effects were getting severe as the temperature increased. Especially when Ca existed as an impurity the detrimental effects was the most severe. These results were resulted from the fact that impurities lowered the mechanical properties of the grain boundary phase of silicon nitride. The wear test results of glass/glass-ceramic specimens having a similar composition to the grain boundary phase of silicon nitride revea-led that the specimen containing CaO showed the lowest wear resistance. The existence of Fe and Ca at the grain boundary phase assisted forming a grain boundary phase with relatively low refractoriness. Therefore at a given wear condition the removal of deformed layer would be easier. The results showed that the glass phases could be modified by heat-treatment and this modification improved tribological characteristics of the silicon nitride.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.67-74
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• 2004

Laser heat treatment is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power $CO_2$ lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching action to occur and the formation of matrensitic structure. In this investigation, the microstructrual features occurring in Nd:YAG laser hardening SM45C and $STD_11$ steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimisation of the processing parameters for maximum hardened depth of SM45C and $STD_11$ steel specimens of 10mm thickness by using CW:YAG laser.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.265-271
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• 1998

High temperature wear behavior of plasma sprayed zirconia based coating sealing with zirconia sol were investigated for high temperature wear resistance application. The zirconia powders containing 2.5, 5.0, 7.5, 10.0 mol% of MoS$_2$, $Fe_2O_3$ for plasma spray were made by spray drying method. As-sprayed coating was sealed by zirconia-sol to fill up the pore and crack in coating. wear test were performed at temperature ranges from room temperature to 600$\circ$C. The microstructural changes of before and after sealing process were examined by SEM, XRD and EPMA. After sealing process, the porosity was decreased and micro-hardness was increased. The wear properties of coating after sealing process were improved by sealing of pores and cracks. The behavior of wear amount and coefficient of friction were same tendency to before sealing process.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.760-765
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• 2000

The study deals with the development of a computational procedure for evaluating the temperature rise in dry and lubricated multi-layered contacts of head/disk interface. A transient computational model with a transformed rectangular computational domain is utilized. A model and a computational method for micro-contact with sub-lubricated zone, including friction heat generation, have been presented. The model was applied, taking full account of the changes in contact area and contact load due to frictional heating. The computational distribution of temperature is obtained with the analytical findings for various composition and contact conditions. Especially, a rapid rise ($220^{\circ}C$ or above) in read head temperature lese to a saturation in the influence of a thermal spike on signal performance. This general class of problems can be treated provided that heat generation distribution and layer properties are known.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1898-1904
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• 2003

Laser heat treatment is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power $CO_{2}$ lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching to occur and the formation of matrensitic structure. In this investigation, the microstructrual features occurring in Nd:YAG laser hardening SM45C and $STD_{11}$ steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimisation of the processing parameters for maximum hardened depth of SM45C and $STD_{11}$ steel specimens of 10mm thickness by using CW Nd:YAG laser.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.113-114
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• 2012

본 연구는 segment target을 사용하여 unbalanced magnetron sputtering을 활용하여 고 CrZr-Si-N 박막을 합성하고 박막의 미세구조 및 마모 특성을 연구하는데 그 목적이 있다. 박막의 Si 함량을 조절하기 위하여 각 segment target은 Cr,Zr을 일정vol% 유지하며 Si vol%만 변화하여 설계하였다. Si 함량별로 제작된 마모실험 시편의 미세구조는 XRD, FE-SEM, AFM, TEM을 통하여 분석하였으며, ball on disk type의 마모 시험기를 통해 그 마모 특성을 분석하였으며,

• Journal of the Korean institute of surface engineering
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• v.30 no.6
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• pp.365-373
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• 1997

316L and 420 Stainless steels were deposited onto AZ9ID commercial magnesium alloy by plasma spray process with various gas flow rate of, TEX>$H_2$ secondary gas. And hardness as well as were track volume, coefficient of friction also had been measured. wear and hardness were measured by using reciprocal configuration tribometer and microghardness tester, respectively. Also, the microstructure of the coatings surface the cross sectional area of coating surface and cross sectional area of coaing/Substrate interface had been analyzed with Scanning Electron Microscope(SEM) and Optical microscope(OM). Finally, optimal process parameters for the improvement of coating efficiency such as mechanical property and wear behavior were examined.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.121-121
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• 2013

수소로 희석된 벤젠 가스를 반응 가스로 이용하여 합성된 DLC 박막의 마찰 마모 특성을 평가하기 위하여, 일반 대기 환경 및 수중 환경에서 마모 실험을 수행하였다. 일반 대기 환경에서는 박막의 기계적 특성, 마찰 계수 및 마모 거동이 거의 변화하지 않았다. 반면, 수중 환경에서는 마찰 계수가 대기 환경에서보다 안정적으로 평가되었다. 이는 DI-water가 윤활제(lubricant) 역할을 하기 때문으로 예측된다. 또, 수중 환경에서의 마모 실험 결과, 수소가 희석되지 않은 반응 가스를 이용하여 증착 된 DLC 박막의 경우, delamination wear가 상대적으로 많이 관찰되었다. 하지만, 반응 가스에 희석 된 수소량이 증가함에 따라서, 이런 delamination wear가 현저하게 억제됨을 관찰하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.139-144
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• 2012

In the automobile industry, the various efforts to lower their industrial cost and enhance fuel efficiency have been made through process improvement or weight saving of automobile parts. Gear is one of significant parts of transmission, which is made by cast iron or alloy steel. It is expensive due to complex processing, inferior materials and large machining allowance. In this study, alternative gear cars oil which is based on fluid applications materials is produced by reducing surface induction hardening and carburizing hardened in production. And then, wear characteristic and mechanical properties such as hardness of the sintered alloy which is used as a substitute for small machining allowance is investigated.

• Transactions of the Society of Information Storage Systems
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• v.10 no.2
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• pp.39-44
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• 2014

LCD panels are used widely in all sorts of devices. Since glass is the main material used to make the panels, scratch resistance is an important issue in acquiring high quality LCD panels. In this work the wear behaviors of three types of commercially available LCD panel glasses were investigated. A pin-on-reciprocating tribotester was used to perform the wear tests using the glass specimens against a stainless steel ball. The hardness of the specimens was initially obtained. It was shown that the wear amount varied with respect to the applied load as well as the type of glass. The wear pattern of the glass specimen was also characterized using confocal microscopy. It is expected that the results of this work will aid in improving the tribological properties of LCD panel glass.