• KSTLE International Journal
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• v.1 no.2
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• pp.91-94
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• 2000

The friction and wear behavior of MoS$_2$coatings was investigated using a pin and disk type tester. The experiment was conducted with silicon nitride as the pin material and MoS$_2$-on-bearing steel as the disk material under different operating conditions that included linear sliding velocities within a range of 2266 mm/sec, normal loads varying from 9.829.4 N, corresponding to maximum contact pressures of 1.782.83 Gpa, and high vacuum, medium vacuum, and ambient air atmospheric conditions. The results showed a low friction coefficient far the coating in a high vacuum, plus the friction coefficient and wear volume increased with an increased normal load. Furthermore, under high load conditions, the friction coefficient and wear volume also increased with an increased sliding velocity.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.79-85
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• 2002

Plasma-sprayed Cr$_2$O$_3$-based coatings containing MoO$_3$were studied to gain a better understanding of the influence of MoO$_3$composition in the coatings on their tribological behaviour. A reciprocal type tribo-tester was employed to examine friction and wear behavior of the specimens at room temperature. The physical characteristics of worn surfaces were investigated by scanning electron microscopy and chemical composition of the coating surfaces was analyzed using a X-ray photoelectron spectrometer. The results showed that friction coefficient of the MoO$_3$-added coatings were lower than those without MoO$_3$addition. However pure Cr$_2$O$_3$coating showed the lowest wear loss at the self-mated test. The larger protecting layers were observed at the worn surface of plasma spray coated specimens with MoO$_3$addition. XPS analysis of the protecting layer indicated that MoO$_3$composition was dominantly formed at the surface. MoO$_3$composition in the protecting layer appears to be more favorable in reducing the friction.

• The Korean Journal of Ceramics
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• v.5 no.2
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• pp.115-118
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• 1999

Carbon composites with $MoSi_2$ dispersion were prepared by hot-pressing at $1700^{\circ}C$ under 30 MPa for 1 h using polysilazance as binding material. The composites consisted of C, $Mo_{4.8}Si_3C_{0.6}$ and SiC. Bulk density and porosity of the carbon composites with 10 vol% $MoSi_2$ was 1.8g.$\textrm{cm}^{-3}$ and 34%, respectively. This composite was oxidized about 0.05mm from the surface of the carbon composite after oxidation test at $1500^{\circ}C$ for 10h in air. Formation of the $SiO_2$ glass layer was observed by SEM. When this composite suffered damage in the coating layer, it had hardly farther oxidation because of its self-repairing property. The composite prepared in this study indicated good oxidation resistance.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1989.11a
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• pp.41-58
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• 1989

현재 자동차엔진유를 비롯한 각종윤활유에 마찰마모방지제 및 산화방지제로 사용되고 있는 유용성 몰리부덴계 화합물은 윤활제의 첨가제로서 주목받고 있다. 이와 같은 유용성 몰리부덴계 화합물은 윤활제의 첨가제로서 마찰부분의 고온에 의해 열분해함으 2 유화몰리부덴($MoS_2$)을 생성하기 위해서 합성한 것이다. $MoS_2$는 마찰마모 감소제로서 잘 알려져 있지만 고체이기 때문에 마찰면에 COATING 하거나 윤활유에 분산시켜 사용하고 있다. 그러나 윤활유에 분산시키는 것과 마찰면에 흡착시키는 것과는 계면화학적 반대현상이므로 문제가 발생하게 된다. 그러므로 윤활유중에 안정한 분산계를 만들어 사용시에는 비교적 안정한 COLLOID 계가 파손되지 않아야 한다. 그러나 열가학적으로 불안정한 COLLOID 계를 유지하기는 어려운 문제이다. 그러므로 유용성인 몰리부덴계 화합물을 윤활유에 용해시켜 열적 혹은 TRIBOCHEMICAL 적으로 분해해 줌으로서 마찰표면에 $MoS_2$의 생성이 필요하다. 이와같은 목적으로 개발된 유용성 몰리부덴화합물은 마찰마모감소작용 및 산화방지작용의 메카니즘에 관해서는 불투명한 점이 많다. 본 논문은 유용성 몰리부덴계 화합물중 Molybdenum dialkyl dithiocarbamate (이후 MoDTC로 명함)를 윤활유 첨가제로 사용해 마찰실험을 통하여 마찰감소작용의 메카니즘을 해명하고, 특히 마찰표면에 생성될 $MoS_2$막의 효과에 관해 중점을 두고 분위기의 효과로 부터 MoDTC의 마찰감소작용의 인자에 대한 고찰을 행하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.96-102
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• 2001

plasma-sprayed Cr$_2$O$_3$-based coatings containing MoO$_3$ were studied to gain a better understanding of the influence of MoO$_3$ composition in the coatings on their tribological behaviour. A reciprocal type tribo-tester was employed to examine friction and wear behavior of the specimens at high temperature(450。C). The physical characteristics of worn surfaces were investigated by scanning electron microscopy and chemical composition of the coating surfaces was analyzed using a X-ray photoelectron spectrometer. The results showed that friction coefficient of the MoO$_3$-added coatings were lower than those without MoO$_3$ addition. The larger protecting layers were observed at the worn surface of plasma spray coated specimens with MoO$_3$ addition. XPS analysis of the protecting layer indicated that MoO$_3$ composition was dominantly formed at the surface. MoO$_3$ composition in the protecting layer appears to be more favorable in reducing the friction.

• Tribology and Lubricants
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• v.34 no.6
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• pp.254-261
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• 2018

In order to reduce resistance torque and energy loss, minimizing friction between race surface and rolling elements of a bearing is necessary. Recently, to reduce friction in bearing element, solid lubricant coating for the bearing raceway surface has been receiving much attention. Considering the operating conditions of real bearings, verifying the effect of solid lubricant coatings under extreme conditions of high load that is more than 1 GPa is necessary. In this study, we evaluated the friction and wear characteristics of SUJ2 bearing steels deposited by carbon-based coatings (Si-DLC, ta-C), $MoS_2$ and graphite. In case of $MoS_2$ and graphite coatings, different surface treatments were applied to the coatings to verify the effect of surface treatment. A pin-on-disc type tribotester was used to evaluate the tribological characteristics of the coatings. It was possible to quantitatively estimate the friction and wear characteristics of solid lubricant under dry and lubrication conditions. The carbon-based coatings improved the friction and wear properties of SUJ2 bearing steels under the high load condition, but $MoS_2$ and graphite coatings were not suitable for high load conditions due to its low hardness. Different friction and wear behaviors were found for different substrate surface treatment method. Also, it was confirmed that solid lubricant coatings had a more positive effect than just applying the lubricant for improving the tribological characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.373-373
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• 2011

$Cu(In,Ga)Se_2$(CIGS) 박막 태양전지는 Chalcopyrite계 박막 태양전지로 Cu, In, Ga, Se 각 원소의 조성을 적절히 조절하여 박막을 성장시킨다. 성장시킨 CIGS 박막은 광흡수계수가 105cm-1로 다른 물질 보다 뛰어나고 직접 천이형 반도체로서 얇은 두께로도 고효율의 박막 제작이 가능하다. 얇은 두께로도 충분히 빛의 흡수가 가능하지만, cell 표면 반사에 의한 광 손실은 cell 효율을 떨어뜨리게 된다. 본 연구에서는 CIGS 박막 태양전지의 광 흡수 향상을 위해 굴절률이 1.86인 ITO 위에 ITO보다 굴절률이 작은 $MgF_2$ (n=1.377) [1]를 80, 100, 120, 140 nm로 증착하여 $MgF_2$/Al/Ni/ITO/i-ZnO/CdS/CIGS/Mo/SLG 시료를 제작하고, optical reflectance, Quantum Efficiency를 이용하여 분석하였다. optical reflectance 분석 결과, $MgF_2$ AR coating을 한 경우, 두께가 두꺼워짐에 따라 광 반사도가 감소하는 경향을 보였다. 또한 AR coating 두께가 커짐에 따라 fluctuation이 점점 커지며, 파형이 장파장 쪽으로 shift하는 것을 관찰 할 수 있었다. Quantum efficiency (QE)를 분석한 결과 $MgF_2$ AR coating 할 경우, 측정된 대부분의 파장에서 QE가 향상되는 것을 확인할 수 있었다. 하지만 AR coating 두께에 따른 변화는 뚜렷한 차이를 보이지 않았다. AR coating 결과, JSC가 증가하여 efficiency가 향상되는 것을 확인 할 수 있다. 그러나 $MgF_2$ AR coating 80~140 nm 범위에서 cell 효율 변화의 뚜렷한 차이는 관찰할 수 없었다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.107-110
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• 2005

Tribological behaviors of carbon epoxy composites whose surfaces have many small grooves were compared with respect to coating method under dry sliding and water lubricating conditions. The surface coating materials were epoxy (Ep) and polyethylene (PE) mixed with self-lubricating $MoS_2$ and PTFE powders. The wear morphology of the composites observed with a scanning electron microscopic (SEM) revealed that the surface coating layer mixed with the self-lubricating powder on the grooved surface significantly improved the wear resistance under water lubricating condition because the surface coating layer blocked water to penetrate the composite surface and the self-lubricating powder reduced the wear on the coating by suppressing the generation of blisters.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1992.06a
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• pp.71-76
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• 1992

초고진공중에 있어서의 기계, 기기의 설계에 있어서 마찰의 제어는 가장 중요한 과제의 하나이다. 지금까지 그 마찰면의 윤활을 위해서는 고체 윤활제로서 Au, Ag 등 $MoS_2$ 피막이 많이 쓰여져 왔다. 또한 그것들의 피막 형성법으로서 Plasma Coating, Sputtering 및 Ion-Plating 등의 여러가지 피막형성법이 개발되어 왔다. 그러나 어느 경우도 형성된 $수\mum$의 피막의 마모에 의한 유한의 수명이 존재하고, 마찰게수의 면에서도 아직 충분하다고 말 할수 없는 것이 현상이다. 이것에 대하여 필자들은 우주에 있어서 사용을 목적으로 새로운 피막 형성법으로서 Tribo-Coating법을 개발하여 그 유효성을 나타내어 왔다. 본 연구에서는 초고진공중에 있어서 Tribo-Coating법에 의한 In막의 윤활 특성에 영향을 미치는 지배적 제인자의 역활을 밝히고져한다.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.348-355
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• 2023

Magnesium secondary batteries are attracting much attention due to their potential to replace conventionally used lithium ion batteries. Magnesium secondary battery cathode material Mo₆S₈ were synthesized by molten salt synthesis method and PVC as a carbon materials were added to improve electrochemical properties. Crystal structure, size and surface of the synthesized anode materials were measured through XRD and SEM. Charge-discharge profiles and rate capabilities were measured by battery test system. 2.81 wt% PVC coated sample showed the best rate capabilities of 85.8 mAh/g at 0.125 C-rate, 69.2 mAh/g at 0.5 C-rate, and 60.5 mAh/g at 1 C-rate.