Improving the Precision of Specifications by Evaluating the Influence of Test Parameters on Tribological Results

Mathias Woydt,Hartwig Weber 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.37 No.-

A series of cooperative interlaboratory tests (round robins) was conducted in 1997, 1998, 1999, 2000, 2001, 2002 and 2003 by the DIN 51834 Working Group on Tribological Tests in Translatory Oscillation Apparatus. The statistical analysis of these test results shows the influence of cleaning solvent, machine model and evaluation criteria on the tribological properties of the lubricants tested. Coefficients of friction and wear results are ranked according to the effects of ten different cleaning solvents, where isopropanol gave the lowest values and isoparaffin solvents the highest. The effect of machine model on coefficients of friction varied from about 0.2 % to 0.9 % of the mean. Wear results were not affected. The tests also showed that the seizure criteria and methods of measuring wear required for in the test procedure do not provide a suitable measure of the tribological properties of some lubricants. The precision was improved by introducing a grease apply caliper as well as an increased stroke to 1,5 mm and running-in. The temperature does not affect the precision of the oil test procedure.

초격자 고경도 나노 다층막 소재의 복합경도 해석을 통한 계면 강화 효과 분석

김성훈,이윤희,박종극,백영준,권동일 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.12

Multilayer coatings consisting of very thin layers of nitride materials deposited by magnetron sputtering (sometimes called superlattices) exhibit hardnesses over 50 GPa, much higher than that of single layers. Several explanations for this hardness increase have been proposed, including dislocation blocking by layer interfaces, Hall- Petch strengthening, strain effects at layer interfaces, and the supermodulus effect. Among these, dislocation blocking has been generally accepted as a dominant factor in large hardness enhancement. However, the interface between two materials consisting of multilayers is broadened due to interdiffusion. The magnitude of hardness enhancement by the interface has not yet been quantified for real systems. In this study, the concept of composite hardness is introduced to quantify the interface-related hardness enhancement. We suggest a composite hardness equation and quantifythe magnitude of hardness increase by using an equation based on the interface hardness and the interface thickness derived by comparing results derived from this equation and those determined in nanoindentation tests. Three multilayer systems, such as TiN/VN, TiN/NbN and CrN/NbN were used in the equation.

Tribological Properties of DLC for Die Applications

Lee, Kyu-Yong,Liu, Zhen-Hua Korean Society of DieMold Engineering 2012 한국금형공학회지 Vol.6 No.1

Friction and wear affect all processes involved in the extraction of materials and their conversion into finished products in the die applications such as drawing, extrusion etc. Originating phenomenon from the contact surface between the tool and workpiece, they are usually a hindrance to materials process operations which usually result in damaging the tools, increasing energy consumption, the contamination of processed material by wear particles and also some problems associated with technologies to control friction and wear. The most well established method to control friction and wear is by the application of lubricant such as fluorocarbon. Besides, a surface technique so-called surface modification can be applied to solve the tribology problems of the die applications for both the economical and ecological reasons. In this article, we applied DLC(diamond-like carbon) thin film on alumina ceramic for HT test using the PIID(plasma ion immersion deposition), 4 groups of test specimens were tested up to $200^{\circ}C$ which is a little higher than the normal working temperature of die application. Pin-on-disc tribo-tester was used to test the friction and surfaces were characterized by SEM and EDS and else, the morphology changes of DLC coatings were studied. The present work indicated that the DLC had a great potential to reduce the friction and wear in the alumina die application without lubricants.

Ni-4.5%Al 피복강재의 마모특성

고장권,김성익,오맹종,김귀식 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

The pin-on-disk type wear testing machine was manufactured using a personal computer, load cell and reduction motor. The tribological properties of Ni-4.5%Al coating steel by flame spray were investigated using this test machine. The experimental result has shown that the wear amount of coating steel was remarkably decreased than the S45C material. In the lubrication environment the wear amount was much less. The friction coefficient of S45C and coating material was respectively 0.4, 0.29 in the air, and it has respectively shown 0.18, 0.24 in the lubrication. Increase of load didn't have effect on the change of the friction coefficient at all.

Pattern 형상이 적용된 베어링 강(STB2)의 트라이볼러지 특성

송석웅 ( S. O. Song ),장태환 ( T. H. Jang ),배문기 ( M. K. Bae ),김태규 ( T. G. Kim ) 한국열처리공학회 2021 熱處理工學會誌 Vol.34 No.3

With the development of the industry, bearings that require higher durability and efficiency are required, and various methods to reduce friction and wear of bearings are being studied. In this study, a wear test was conducted for STB2, a bearing steel material, by machining a micro-line pattern on the race surface of the bearing by machining. The pattern pitch of the specimens was processed to 40μm, 80μm, and 150μm, and the coefficient of friction characteristics were investigated for the unpatterned specimen and the specimen with a DLC thin film deposited on the surface. As a result of the wear test, the pattern pitch showed the smallest coefficient of friction at 40μm, and it was confirmed that the smaller the pattern pitch, the better the tribology characteristics. (Received May 6, 2021; Revised May 17, 2021; Accepted May 21, 2021)

기계요소의 가속시험방법에 대한 트라이볼로지적 접근

김현준(Hyun-Joon Kim),김대은(Dae-Eun Kim),김형의(Hyung-Eui Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Reliability is a key concern of all machines that must maintain good operating conditions. There are many mechanisms of damage that lead to the failure of the system. In this presentation, the tribological approach to performing accelerated wear test of mechanical components is discussed. In order to accelerate the wear effect the mechanism of wear must first be understood. The mechanisms of wear for various applications are presented. Also, the use of Stribeck curve and Archard's wear equation in determining the acceleration parameters are proposed. By selecting the proper speed, load, and lubrication condition in the wear test, the failure due to wear can be accelerated.

Syntheses and Tribological Characteristics of Alkanediol Derivatives Containing Dialkyldithiophosphoric Acid

남석현,고경민,조정은,김영운,정노희,강호철 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Zinc dialkyldithiophosphate(ZDDP) is a lubricant additive, which is most widely used due to its economics, performance of antioxidant, prevent of abrasion, and etc. But ZDDP contains heavy metals such as zinc, manganese, increasing the emission of heavy metal contamination of soil and ocean. This study synthesised anti-wear additives without heavy metals in a simple and efficient manner by using alkanediol derivatives. A four-ball wear test was performed to examine tribological performance in relation to the carbon chain length of the alkanediol for the synthesised additives (B8P4, B8P6, B8P9, B8P11, and B8P13), the number of carbons for principal alkyl chain was varied from 4 to 13. The wear scar diameter(WSD) was 0.459 mm for 4 carbons, 0.472 mm for 6, 0.461 mm for 9, 0.480 mm for 11 and 0.468 mm for 13. It was confirmed that there was no significant difference. Among these, a comparison test of the properties of B8P9 and ZDDP was carried out.

Si 함유량에 따른 Si-DLC/DLC 코팅의 건조마찰 특성

안효석(Hyo-Sok Ahn) 한국생산제조학회 2007 한국공작기계학회 춘계학술대회논문집 Vol.2007 No.-

Although DLC coatings have good tribological properties, these are dependant on the deposition method, property of contact surface, and test condition. Si-DLC/DLC coatings with various Si content were deposited on Si substrates and tested using a reciprocating friction tester against steel balls. The results revealed that the tribological behavior of Si-DLC/DLC coatings was dependant on the Si content. The formation of transfer film and wear particles on the contact surface was greatly influenced by the Si content in DLC coatings. In particular, silicon oxide transfer film formed by tribochemical reaction contributed to reduce wear and friction.

상대 마찰재에 따른 DLC 코팅의 트라이볼로지적 특성평가

이동춘(Dong Choon Lee),이진우(Jin-Woo Yi),김석삼(Seock Sam Kim) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.37 No.-

Diamond-like carbon(DLC) films are considerable research interest because of their widespread applications as protective coatings in areas such as optical windows, magnetic storage disks, car parts, biomedical coatings and as micro-electromechanical devices(MEMs). DLC films were deposited on WC-Co by PECVD using Ar, C₂H₄ gas. Tribological tests were conducted using a ball-on-disk type tribometer in dry air. Three kinds of counter-bodies balls were used. The counter-bodies balls are SM45C, SUJ2 and ZrO₂(3.17㎜ in diameter). Wear rate of the samples were calculated afer measuring the worn-out volume of the wear track. As results wear test, the higher hardness of counter-bodies, friction coefficient low. As result of XPS estimation, wear debris generated as an oxide lower the friction coefficient.

Synergistic Effect of a Coating and Nano-Oil Lubricant on the Tribological Properties of Friction Surfaces

Cho, Yong-Il,Park, Jung-Hoon,Ku, Bon-Cheol,Lee, Jae-Keun,Park, Warn-Gyu,Lee, Jae-Yeol,Kim, Soo-Hyung 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.1

In this study, we evaluated the tribological properties of grey cast iron (GC200) surfaces with and without $MoS_2$ coating that were lubricated with either mineral oil or mineral oil in which fullerene nanoparticles were dispersed (i.e., nano-oil), by using a disk-on-disk type tribotester. A series of friction tests were performed using the disk-on-disk type tribotester under various normal forces, and the friction coefficient and friction surface temperature were monitored simultaneously. First, we observed that the friction coefficient of the GC200 surface that has a $MoS_2$ coating and is lubricated with mineral oil was 32% lower than that of the GC200 surface without a $MoS_2$ coating. Second, we found that the friction coefficient of GC200 surfaces lubricated with nano-oil was approximately 74% lower than that of GC200 surfaces lubricated with mineral oil. This suggested that the effectiveness of nano-oil lubrication in reducing the friction between GC200 surfaces is considerably higher than that of $MoS_2$ coating or mineral-oil lubrication. In order to examine the effects of both the coating and nano-oil lubrication, friction tests for $MoS_2$-coated GC200 surfaces under nano-oil lubrication was performed. We observed the following: (i) the friction coefficient of $MoS_2$-coated GC200 surfaces lubricated with nano-oil were approximately 82% lower than that of uncoated GC200 surfaces lubricated with mineral oil; (ii) the nano-oil lubrication even tended to prevent the coating from peeling off, presumably because the fullerene nanoparticles added in the mineral oil acted as ball bearings. These observations suggested that the presence of a coating on friction surfaces and the addition of nanoparticles in mineral oil lubricant have a synergistic effect in significantly reducing the friction between friction surfaces.