• Elastomers and Composites
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• v.49 no.1
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• pp.73-81
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• 2014

Friction and wear behaviors of natural rubber(NR) compounds were investigated using a blade-type abrader. The effects of temperature, normal load, and rotation speed on wear rate were studied, and wear behaviors of deteriorated compounds were also evaluated. As the rotation speed of specimen and the normal load to specimen increased, the wear rate increased. However, as the experimental temperature increased, the frictional coefficient decreased and the wear rate decreased accordingly. It was found from the wear studies that a power-law relation works between the frictional work input and the wear rate. It was observed that the wear rate dramatically increased by the degradation of the rubber specimen. The wear pattern was developed and the bigger ridge space of the pattern was observed usually in the higher normal load applied. In determining the wear rate of rubber compound, the continuous measurements of wear distance using the blade-type abrader could be successfully used instead of intermittent measurements of wear-loss weight.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1990.11a
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• pp.1-15
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• 1990

엔진 성능의 향상에 맞추고 에너지 절약을 위한 방법으로써 엔진 오일의 마찰 마모 특성등 오일의 성능을 높이려는 노력이 꾸준히 시도되고 있다. 특히 마찰력 손실을 감소기키기 위해서 낮은 마찰특성을 갖도록 몰리브데늄(Mo)을 유용성인 금속 착화합물로 만든 Mo-DTP를 제조하여 현재 첨가제로 널리 사용되는 Zn-DTP와 대체시키려는 연구가 활발하고 최근엠 많은 논문이 발표되고 있다. 또 일부 윤활유 제조 회사에서는 몰리브레늄을 첨가 시키는 등 제품 기술을 향상시켜 오일 교환의 기간이나 자동차 주행 거리를 대폭적으로 늘려줄 수 있는 상품도 생산되고 있다. 윤활 첨가제로써 Mo-DTP를 Zn-DTP와 대체시켜 기유에 혼합한 경우에는 마찰 감소 기능이 매우 향상 되었고 내 마모성도 비교적 좋으나 산화 억제 능력이 부족하고 온도의 상승에 따른 점도 지수의 증가도 비교적 크다는 단점을 갖고 있음이 발표된바 있다. 따라서 Mo-DTP의 단점을 보완하려는 연구가 필요되고 그의 한 방법으로써 현재 첨가제로 가장 많이 사용되는 Zn-DTP와 혼합하여 첨가 하였을 경우에 대한 연구를 하였다. 이때 기본 윤활유에 Mo-DTP와 Zn-DTP를 적당한 혼합 비율로 첨가하고 하중, 온도를 변화 시키면서 마찰, 마모등의 성질고 산화 안정성 및 마모 입자 분석 등 전반적인 윤활유로써의 특성을 살펴 보았다.

• The Korean Journal of Rheology
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• v.7 no.1
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• pp.50-59
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• 1995

겨울용 타이어인 '발포고무 타이어'의 트레드에 적용되는 발포고무의 물성과 마찰 및 마모특성을 조사하였다. 천연고무인 SMR-CV60과 합성고무인 BR-01(Cis-1, 4 Polybutadiene)을 70:30 비율로 혼합하였고 발포제로는 개질화된 azodicarbonamide (상품 명:UNICELL AD#2)을 변량 첨가하여 다양한 발포도의 발포고무를 준비하였다. 발포도의 증 가로 발포고무의 Young's modulus와 파괴에너지는 점진적으로 감소하였으나 Tan $\delta$ 는 일정한 값을 유지하였다. 매끄러운 유리표면위에서 높은 마찰계수를 보인 발포고무는 발포 도의 증가로 크게 감소하였고 거친 표면일수록 마찰계수는 상승하였다. 이같은 마찰계수의 증감경향이 교차되는 발포도는 30~40%이었다. $0^{\circ}C$에서의 마찰계수도 유리 표면에서감소하 고 거친표면에서 상승하는 경향을 보였으며 증감경향이 교차하는 발포도는 20%로 낮아졌 다. 마찰표면을 마그네시아 분말로 처리하면 전반적으로 마찰계수는 감소하였고 발포도의 크기에 관계없이 마찰표면이 거칠수록 큰 마찰계수를 나타내었다. 발포고무의 발포도가 커 지면 마모손실량도 비례하여 증가하였으며 발포도가 낮은 고무에서는 비교적 규칙적인 융기 간격이 보였으나 발포도가 30%이상으로 되면 불규칙적인 마모표면과 더불어 많은 마모 부 스러기가 관찰되었다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.561-568
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• 2021

In this study, in order to observe the change in the amount of Tire and Road Wear Particles and the ratio of tire components in it according to the tire wear resistance performance, carried out the evaluation by varying the vulcanization reaction design of the tire tread rubber. In addition, in order to improve the reliability of the evaluation of Tire and Road Wear Particles, the evaluation was performed indoor laboratory test equipment that simulates the condition on real driving to exclude various environmental influences including minerals, driver's habits, road surface, weather, tire structure and pattern designs. After the evaluation in closed space, it is estimated that the amount of collected Tire and Road Wear Particles is 84% compared to 100% of the tire and road wear loss weight, of which 96.4~97.7% was around the road and 2.3~3.6% was in the air. As a result of analy sis of the collected Tire and Road Wear particles, the tire component existed 63~75% in the Tire and Road Wear Particles depending on the wear resistance performance of the tire.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.410-418
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• 2015

A slider of the pantograph undergoes uneven and abnormal wear due to sliding contact with the catenary. In the case of rain, the loss of lubricant increases the frictional resistance for the reciprocating motion between the catenary and the slider, accelerating local wear. The slider in the winter should have good wear resistance, which can be achieved through alloy design. Uneven and abnormal wear were not observed in the results of a driving test using a wear resistant slider. It was found that the increased density of the slider enhanced the corrosive effects of Fe-Ti, preventing the occurrence of abnormal wear by maintaining the wear and arc resistance in the rainy season. Also, mechanical and electrical wear did not affect the composition of the slider, and this improved the wear resistance. Inaddition, the slider was applied to an entire train and was tested during driving; ananalysis of the correlation of the catenary was performed, including during the rainy season and the winter season.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.202-202
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• 2016

API X-80강재의 수소유기균열(HIC)현상을 비파괴적으로 평가하는 장치를 구축하고 금상학적 평가를 수행하였다. 시편은 열간 압연된 API X-80강재이며 평균입도는 약 $1.76-1.99{\mu}m$ 이었다. 압연재의 금상학적 집합조직은 (110)극점은 ND방향에 평행, (100)극점은 TD방향으로 약 $30^{\circ}$, TD방향으로부터 RD방향으로 약 $45^{\circ}$ 기울어져 있으며, (211)면은 RD방향에 수직인 면으로부터 TD방향으로 약 $35^{\circ}$ 기울어져서 있었다. Pin-on-disk형 마모시험기를 이용한 상온 평균 마찰계수는 0.745였으며 마모손실은 0.0196 mm/min 이었다. 3축 제어 초음파 비파괴 검사 장비는 표면으로부터 약 3mm 깊이의 1 mm 크기의 모의 균열을 탐촉자가 10 mm 접근하면 검출이 가능하였다. HIC시험분위기(NACE-standard TM 0248)에 1일 이상 장입하면 초음파비파괴검사장비로 측정될 수 있는 마이크로미터크기의 균열을 측정할 수 있었다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.467-468
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• 1999

여과집진장치는 기존의 집진장치 중에서 집진효율이 가장 우수하나, 여과집진에서 필연적으로 발생하는 높은 압력손실과 탈진에 따른 여과포의 마모, 그리고 고온조건에서의 성능저하 등은 여과집진장치의 광범위한 적용을 저해하는 요인으로 작용해왔다. 탈진에 따른 여과포의 손상을 막고, 먼지입자의 표면여과를 극대화시키는 방법으로 기존의 여과포에 박막을 입히는 방법이 많은 연구자들에 의해 개발되어 왔다.(중략)

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.3
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• pp.238-244
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• 2017

Pathologic attrition leads to pathologic damage on occlusal plane, functional disorders, occlusal disharmony, esthetic problems, pulpal lesion, temporomandibular joint (TMJ) disorder. In this case, treatment plan should be considered for possibility of vertical dimension loss, occlusal pattern, esthetics, phonetics, amount of vertical dimension increase. This case report was a 71-year-old man who had severely worn dentition. Full mouth rehabilitation was carried out with vertical dimension increase due to limited space for prosthesis. After evaluation of provisional restorations for patient's compliance, final restorations were fabricated and routine clinical assessments were made. This case presents that a satisfactory clinical result was achieved by restoring the worn dentition.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.190-201
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• 2004

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four esthetic restorative materials in an alkaline solution. The brands studied were Charmfil, Charmfil flow(composite resin), Compoglass F and PrimaFlow(compomer). The results were as follows: 1. The mass loss were not significantly different among the materials(p>0.05). 2. The sequence of the degree of degradation layer depth was in descending order by Compoglass F, PrimaFlow, Charmfil, and Charmfil flow. There were significant differences between Compoglass F and the others(p<0.05). 3. The sequence of the Si loss was in descending order by Charmfil flow, Charmfil, PrimaFlow, and Compoglass F. There were significant differences among these materials(p<0.05). 4. When observed with SEM, destruction of bonding between matrix and filler was observed and when observed with CLSM, the depth of degradation layer of specimen surface was observed. 5. The sequence of maximum wear depth was in descending order by Comfoglass, PrimaFlow Charmal, and Charmfil flow. There were significant differences among these materials(p<0.05). 6. The correlation coefficient between Si loss and degradation layer depth (r=0.602, p<0.05) Vicker's hardness number and maximum wear depth (r=0.501, p<0.05) were relatively high. These results indicate that wear and hydrolytic degradation may be considered to be evaluation factors of composite resins and compomers.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1183-1188
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• 2013

The reliability of hydraulic equipment used in power plants is especially important because failures that occur in the power plant can have a great ripple effect on human lives and financial losses. In this study, specimens using the materials used in the spool and sleeve of hydraulic valves of power plants have been produced, heat-treated, and tested under the precipitation conditions of phosphate ester hydraulic fluid with a variety of conditions. 23 full factorial designs have been applied to evaluate the significance of factors that affect the wear loss of the specimen, specifically, the load, velocity, and temperature. The significance evaluation was performed on the main effects and two-way interactions for wear loss based on the experiment results, and the mathematical equations between the wear loss and the three factors were derived from the analysis results.