• Tribology and Lubricants
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• v.35 no.1
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• pp.1-8
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• 2019

Demand for plastic gears are increasing in many industries due to their low production cost, light weight, applicability without lubricant, corrosion resistance and high resilience. Despite these benefits, utilizing plastic gears is limited due to their poor material properties. In this work, DLC coating was applied to improve the tribological properties of polyamide66 gear. 0 V, 40 V, and 70 V of negative bias voltages were selected as a deposition parameter in DC magnetron sputtering system. Pin-on-disk experiment was performed in order to investigate the wear characteristics of the gears. The results of the pin-on-disk experiment showed that DLC coated polyamide66 with 40 V of negative bias voltage had the lowest friction coefficient value (0.134) and DLC coated PA66 with 0 V of negative bias voltage showed the best wear resistance ($9.83{\times}10^{-10}mm^3/N{\cdot}mm$) among all the specimens. Based on these results, durability tests were conducted for DLC coated polyamide66 gears with 0 V of negative bias voltage. The tests showed that the temperature of the uncoated polyamide66 gear increased to about $37^{\circ}C$ while the DLC coated gear saturated at about $25^{\circ}C$. Also, the power transmission efficiency of the DLC coated gear increased by about 6% compared to those without coating. Weight loss of the polyamide66 gears were reduced by about 73%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.467-470
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• 2004

Diamond-Like Carbon (DLC) thin film is a semiconductor with high mechanical hardness, low friction coefficient, high chemical inertness, and optical transparency. DLC thin films have widespread applications as protective coatings and solid lubricant coatings in areas such as Hard Disk Drive (HDD) and Micro-Electro-Mechanical-Systems (MEMS). In this work, the wear characteristics of DLC thin films deposited on silicon substrates using a DC-magnetron sputtering system were analyzed. The wear tracks were measured with an Atomic Force Microscope (AFM). To identify the sp2 and sp3 hybridization of carbon bonds and other bonds Raman spectroscopy was used. The structural information of DLC thin films was obtained with Fourier transform infrared spectroscopy and wear tests were conducted by using a micro-pin-on-reciprocator tester. Results showed that the wear characteristics were dependent on the sputtering conditions. The wear rate could be correlated with the bonding state of the DLC thin film.

• Journal of Power System Engineering
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• v.6 no.4
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• pp.56-61
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• 2002

This study is to investigate the wear behaviors of thermally sprayed ceramic coating by a pin-on-disk wear testing machine. The test specimens were plasma sprayed TiO2 coating material on carbon steel substrate(S45C) with Ni-4.5%Al alloy bond coating. Wear characteristics, friction coefficient and wear rates, were conducted at the three kinds of loads and velosities. Wear environments were dry and lubrication friction. The friction coefficients of TiO2 coating specimen in dry friction were almost same according to increase the friction velocity. The wear rate increased when the friction force is high. In lubrication friction, the wear hardly occured and friction coefficient was about 0.1. The adhesiveness of TiO2 in lubrication friction is larger than that in dry one.

• KSTLE International Journal
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• v.9 no.1_2
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• pp.17-21
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• 2008

The rolling piston type rotary compressor has been widely used for refrigeration and air-conditioning systems due to its compactness and high-speed operation. The present study is one of studies to maximize the advantages of refrigerant compressors. In addition, because friction characteristics of the critical sliding component is essential in the design of refrigerant compressors, the present study also analyzed the lubrication characteristics of a rotary compressor used for refrigeration and air-conditioning systems. In order to measure the friction force between the vane and the rolling piston, an experimental apparatus known as the Pin-on-Disk was used. Load is applied by the hydraulic servo valve controlling the pressure of the hydraulic cylinder. The results showed that the rotational speed of the shaft, the operating temperature, and the discharge pressure significantly influenced the friction force between the vane and the rolling piston.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.28-28
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• 2003

고온가압소결(Hot Pressing) 된 다이아몬드 공구용 Co-Fe, Co-Ni계 금속본드의 상온 건식 미끄럼 마멸시험을 행하고, 조성에 따른 각 본드의 마멸 특성을 비교하고 마멸 기구를 규명하였다. 미끄럼 마멸시험은 pin-on-disk 형태의 마멸시험기를 사용하여 각 조성의 성분, 적용하중 그리고 마멸상대재를 변수로 상온, 대기 중에서 실시되었다. 마멸속도는 마멸시험 전후의 시편의 무게 감량을 이론밀도와 거리로 나누어 계산되었다. 마멸기구의 규명을 위하여 시험된 시편의 마멸면과 마멸단면을 SEM과 EDS를 이용하여 분석하였다. 시험 결과 Co-Fe system의 경우 그 마멸속도는 마멸상대재의 영향보다는 Fe 첨가에 따른 시편의 미세조직과 기계적 성질의 차이에 따라 크게 변화하였다. 그러나 Co-Ni system의 마멸속도는 마멸 상대재에 따라 크게 변화하는 것이 관찰되었다. $Al_2$O$_3$를 상대재로 마멸된 경우에는 마멸속도가 시편/상대재 접촉면에서 형성되는 산화층의 영향을 크게 받았고, glass bead(83% SiO$_2$)를 상대재로 한 경우에는 시편의 경도와 마멸속도는 서로 반비례하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.53-60
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• 2000

Organic brake materials are installed in the braking system of korean model combat vehicles. Since the binder resin is decomposed in high temperature region, it may possible to drop the friction force which makes the vehicle stop within the desired distance. This study analyses the braking performance of the brake materials in high temperature region by using the pin-on-disk type friction tester. It is observed radical drop of friction coefficients and rapid increase of wear amounts from the transition temperature. It is due to the formation of oxide layer on the friction surface.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.04b
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• pp.60-67
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• 1996

This paper was undertaken to analyze the morphology of wear debris on operating condition of lubricated machine surfaces. The lubricating wear test was carried out under different experimental conditions using the wear test device was made in our laboritory and wear testing spcimen of the pin on disk type was rubbed in paraffine series base oil, by varying specimen, applied load, sliding distance. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) to describe morphology of wear debris have been developed and are outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology for machine condition monitoring.

• Tribology and Lubricants
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• v.11 no.3
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• pp.24-30
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• 1995

This paper was undertaken to recognize the pattern of the wear debris by neural network as a link for the development of diagnosis system for movable condition of the lubricated machine surface. The wear test was carried out under different experimental conditions using the wear test device was made in laboratory and wear testing specimen of the pin-on-disk type were rubbed in paraffine series base oil, by varying applied load, sliding distance and mating material. The neural network has been used to pattern recognition of four parameter (diameter, elongation, complex and contrast) of the wear debris and learned the friction condition of five values (material 3, applied load 1, sliding distance 1). The three kinds of the wear debris had a different pattern characteristic and recognized the friction condition and materials very well by the neural network. The characteristic parameter of the large wear debris over a few micron size enlarged recognition ability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.19-28
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• 2020

The spacer, which is located between the bucket and the arm of an excavator, has a role in preventing damage to the excavator arm during excavation work. When the durability of the spacer is increased, the lifetime of the arm can be extended and the processing costs can be reduced. To increase the durability of the spacer, tungsten carbide (WC) coating was applied on the surface of a spacer using the plasma transferred arc (PTA) process. The confirm the durability, a wear test using a pin-on disk type of wear testing machine was done under the given conditions and the wear amount on the surface of a tested specimen was measured using reflective digital holography. The results were compared with that of ALPHA-STEP.

• Tribology and Lubricants
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• v.19 no.3
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• pp.146-150
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• 2003

The natural refrigerant $CO_2$has attracted as an alternative refrigerant currently used in air conditioning system, which has high global warming potential. In this study, the tribological characteristics of the sliding surfaces between a fixed scroll and an orbiting scroll of the scroll compressor were investigated in $CO_2$/ POE mixed environment. The pin-on-disk type sliding tests were carried out under the various sliding speeds, normal loads. surface roughness, and pressures. During the test, friction forces, wear amount and surface temperature were monitored.