• Tribology and Lubricants
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• 제24권6호
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• pp.297-301
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• 2008

In many dynamic seals such as lip seal and compression packings, it is well known that wear occur at the surface of heat treated steel shaft as results of the intervened wear particle. It is widely understood that the dominant wear mechanism related in sealing surfaces is abrasive wear. However, little analytical and experimental studies about this problems have been done until now. In this paper, a contact analysis is carried out using MARC to investigate the wear mechanism in contact seal applications considering elastomeric seal, a elastic perfect-plastic micro-spherical particle and steel surface. Deformed seal shapes, contact and von-Mises stress distributions for various particle sizes and interference are showed. The maximum von-Mises stress within steel shaft was exceeded its yield strength and plastic deformation occurred at steel surface. Therefore, the sealing surface can be also worn by sub-surface fatigue due to wear particles together with well known abrasion. The numerical methods and models used in this paper can be applied in design of dynamic sealing systems, and further intensive studies are required.

• 열처리공학회지
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• 제20권2호
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• pp.72-77
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• 2007

Abrasive wear between piston ring face and cylinder liner is an extremely unpredictable and hard-to-reproduce phenomenon that significantly decreases engine performance. Wear by abrasion are forms of wear caused by contact between a particle and solid material. Abrasive wear is the loss of material by the passage of hard particles over a surface. From the pin-on-disk test, particle dent test and scuffing test, abrasive wear characteristics of diesel engine cylinder liner-piston ring have been investigated. Pin-on-disk test results indicate that abrasive wear resistance is not simply related to the hardness of materials, but is influenced also by the microstructure, temperature, lubricity and micro- fracture properties. In particle dent test, dent resistance stress decreases with increasing temperature. From the scuffing test by using pin-on-disk tester, scuffing mechanisms for the soft coating and hard coating were proposed and experimentally confirmed.

• 동력기계공학회지
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• 제18권6호
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• pp.58-63
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• 2014

This paper deals with the effects of counterpart materials on the wear behavior of thermally sprayed STS316 coatings. STS316 powders were flame-sprayed onto a carbon steel substrate. Dry sliding wear tests were performed using the applied loads of 15 N. AISI52100, $Al_2O_3$, $ZrO_2$ and $Si_3N_4$ balls were used as counterpart materials. Wear behavior of STS316 coatings against different counterpart materials were studied using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that the wear behavior of thermally sprayed STS316 coatings strongly depends on the type of counterpart material. Dominant wear mechanism was similar for all studied materials as failure of adhesion film except for Si3N4 used as counterpart material. In the case of Si3N4 used as counterpart material, dominant wear mechanism was abrasion.

• 대한치과보철학회지
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• 제33권2호
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• pp.210-230
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• 1995

To compare the wear resistance of four kinds of commercial acrylic resin teeth [SR-Orthosit PosterioresR(Ivoclar Co., Liechtenstein), Endura PosteriorR(Shofu Inc. Japan), trubyte IPN teethR(Dentsply International Inc., York,), Trubyte BiotoneR(dentsply Inermational Inc. Brazil) by means of the toothbrush abrasion method, the artificial resin teeth were embedded in epoxy resin with the occlusal surfaces aligned in one plane for a total of 40 blocks. There after, each lock was mounted in the arm of the toothbrush abrasion machine(K 236, Japan). Wear measurements were made on the three preconditioned states. Those were as follows : no treatment specimens, thermocycled specimens, and thermocycled specimens which were immeresed applied load of 400g during the buring the brushing cycle. At the end of the 30,000-stroke cycle, each specimen was removed, and weighed. The microhardness of four kinds of commercial resin teeth were determined by means of microhardness tester. Microhardness tests were performed on te no treatment specimens, thermocycled specimens, and thermocycled specimens with immersion in the denture cleansing solution. Finally, the comparison of thermal properties were perfomed using differential scanning calorimeter(DSC-1500). The following results were obtained : 1. In the case of no treatment teeth, the wear amount of endura Posterior(EN) was the greatest among the others(p<0.01), and the wear amount of three kinds of artificial resin teeth was increased in the order of Trubyte IPN teeth(IN), Trubyte Biotone(BN), SR-Orthosit Posteriores(SN) but there was no statistic significance(p>0.01). 2. The wear amount of Trubyte IPN teeth(IT) and Trubyte Biotone(BT), was increased due to thermocycling effect, but that of Endura Posteriores(ET) was decreased conversely(p<0.01). 3. Except for the SR-Orthosit Posteriores(STC), the wear amount of three kinds of artificial resing teeth(that is, ETC, ITC, BTC) was increased due to denture cleansing solution$(Cledent^R)$, but there was no statistic significance(p>0.01). But the wear amount of the SR-Orthosit Posteriores(STC) was the greatest among the others(p<0.01). 4. The wear amount of toothbrush was the greatest in case of contact with occlusal surface of SROrthosit Posteriores resin teeth(p<0.01). 5. the microhardness values(KHN) of the SR-Orthosit Posteriores was the highest among the experimental artificial resin teeth(p<0.01). 6. There was no relationship between microhardness valuse(KHN) and wear amount of four kinds of experimental artificial resin teeth(p<0.01). 7. The differential canning calorimetric property of four kinds of artificial resin teeth did not show endothermal or exothermal peak in the range of $100^{\circ}C$

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.38-48
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• 1998

To apply the high chromium white cast irons for sliding parts of construction equipments, the wear characteristics of these alloys which have three kinds of microstructure(hypoeutectic, near-eutectic, hypereutectic) were investigated by dry sand/rubber wheel tester. Also, the effect of heat treatment was investigated for the same alloys. As result of the test, heat treatment have no effect on the wear characteristics. And, hypereutectic composition alloy has the highest wear resistance against SiO$_2$. Also after test, cracking was observed in eutectic and primary carbides of all materials tested. This phenomenon was important factor in the wear resistance.

• 한국세라믹학회지
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• 제31권5호
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• pp.520-528
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• 1994

An investigation was carried out to understand the effect of the amount of free silicon on the tribological properties of Si-SiC. The specimens of dense Si-SiC composites with various amount of free silicon were fabricated in the temperature of 175$0^{\circ}C$ after molding under various pressure. Wear properties were measured by ball-on-plate wear tester under the constant weight of 4 Kgf at constant sliding speed of 500 mm/sec in water. As the result, the Rockwell hardness and fracture strength of Si-SiC composites remained nearly constant up to 16.62 vol% of free silicon in the Si-SiC microstructure. The Si-SiC composites containing the free silicon of 16.62 vol% was considered to be prominent in the tribological properties, which had the friction coefficient of 0.08 and the specific wear rate of 2.4$\times$10-8$\textrm{mm}^2$Kgf-1. The analysis of the wear surface indicated the complicated processes occuring on the surface such as fine polishing, abrasion, microfracture.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2003년도 추계학술발표대회 요약집
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• pp.418-418
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• 2003

• Elastomers and Composites
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• 제41권3호
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• pp.194-204
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• 2006

본 연구에서는 카본블랙 충전제의 입자크기 및 구조에 따른 고무 배합물의 마찰 마모 특성을 고찰하였다. 카본블랙의 입자크기와 구조에 따라 마모속도 및 형상이 다르게 되며, 최적 마모성능을 설계하기 위해서는 충전제의 입자크기와 구조의 마모 영향도를 사용조건에 따라 고려하여야 한다. 충전제의 입자크기와 구조에 따른 마모속도($W_R$) 영향도를 수준별로 고찰하기 위해 본 연구에서는 구조와 입자크기가 다른 10가지의 카본블랙을 선택하여 동일한 양을 천연고무와 배합하였다. 자체 제작한 칼날형 마찰 마모 시험기를 이용하여 마찰 마모 특성을 평가하였고, 카본블랙의 입자크기와 구조의 영향을 고려한 특성인자(${\psi}=\sqrt{{N_2^2}+{DBP^2}}$)와의 관계를 고찰하였다. 마모속도($W_R$)와 마찰일($W_f$)의 간에는 power-law 관계가 있었으며, 마모속도는 카본블랙의 특성인자에 역비례 관계를 보였다. 이는 카본블랙의 입자 크기가 작고 구조가 잘 발달 될수록 마모 저항특성은 향상된다는 것을 나타낸다.

• 대한치과보철학회지
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• 제37권3호
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• pp.313-327
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• 1999

The aim of this study was to compare wear resistance of resin denture teeth opposing various restorative materials. The wear resistance of conventional acrylic resin teeth(Trubyte Biotone) and three high-strength resin teeth(Bioform IPN, Endura, SR-Orthosit-PE) opposing different restorative materials(gold alloys, dental porcelain, composite resin) was compared. Wear tests were conducted with a sliding-induced wear testing apparatus which applied 100,000 strokes to the specimen in a mesio-distal direction under conditions of 100 stroke/min and constant loading of 1Kgf/tooth. Wear resistance of the resin denture teeth was evaluated by the following criteria : 1) wear depth, 2) weight loss, and 3) SEM observation. Results were as follows. 1. When opposed to gold alloys and composite resin, high-strength resin teeth showed superior wear resistance compared to acrylic resin teeth. But, in cases opposing dental porcelain, differences between the wear of the high-strength and acrylic resin teeth were not statistically significant (p<0.05). 2. When comparing wear resistance among high-strength resin teeth, opposing gold alloys, Endura was slightly more resistant and while in cases opposing dental porcelain, SR-Orthosit-PE was showed to be slightly resistant(p<0.05). 3. The wear of high-strength resin teeth was greater by 5 to 7 times when opposing porcelain and 2 to 3 times when opposing composite resin compared to gold alloys(p<0.05). 4. SEM observations of the wear surface showed that wear of resin teeth opposing gold alloys is a fatigue type of wear and wear of resin teeth opposing dental porcelain is fatigue and abrasion type of wear. Trubyte Biotone showed more severe fatigue type of wear than high-strength resin teeth. In conclusion, the use of dental porcelain should seriously be considered as restorative material in cases opposing resin denture teeth and improvement seems to be needed on resin teeth in the areas of wear resistance.

• 구강회복응용과학지
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• 제21권1호
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• pp.69-81
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• 2005

The objective of this study was to evaluate the toothbrush abrasion characteristics of class V restorations. Thirty extracted human premolars, which were collected from oral surgery clinics were used. We mounted five teeth in a metal ring mold of 50 mm in diameter and 15 mm in height using chemically cured acrylic resin. Class V cavities were prepared in lingual cervical root surfaces and restored using one of following restorative materials : Dentin Conditioner/Fuji II LC (Group FL), All Bond II/Z-250 (Group ZT), One-up Bond F/Palfigue Estelite (Group PE), F2000 Primer/Adhesive (Group FT), and Prime & Bond 2.1/Dyract AP (Group DR). They were stored under distilled water at $37^{\circ}C$ for seven days. The toothbrush abrasion test was conducted using a wear testing machine of pin-on disk type under a load of 1.5 N for 100,000 cycles. We have examined the bonded interfaces, the changes of surface roughness and color of abraded surfaces. From this experiment, the following results were obtained. 1. The change of surface roughness showed high degree: RMGIC>compomer>composite resin (p<0.05). 2. Because of the protrusion and missing of filler particles, SEM observation of abraded surfaces of RMGIC and compomers revealed the increase of surface roughness due to the selective removal of matrix resin. 3. The color change by toothbrush abrasion was affected in large part by the change of $L^*$ and $b^*$ of resin composites (p<0.05). 4. The color change by toothbrush abrasion was so small to detect by human eyes. 5. SEM observation of abraded surfaces revealed the interface bonding was the best in the FT group.