• Tribology and Lubricants
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• 제11권5호
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• pp.184-189
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• 1995

The antiwear performance of dialkyl 3, 5-di-t-butyl 4-hydroxy benzyl phosphonates was investigated using a four ball wear test machine. Diethyl 3, 5-di-t-butyl 4-hydroxy benzyl phosphonate (DEP) and dibutyl 3,5-di-t-butyl 4-hydroxy benzyl phosponate (DBP) among them showed excellent antiwear performances compared with conventional additives, ZDDP and TCP as the bulk oil temperature and the sliding velocity increased. The surface analysis through an optical microscopy was conducted for tribological studies.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.189-194
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• 1999

The antiwear performance of several organic phosphates ,such as tricrecylphosphate(TCP), tributylphosphate(TBP), diphenylhydrogenphosphate(DPHP) ,dissolved in polyol ester based oils is studied. These organic phosphates are well known for antiwear additive for lubricating oil that produce reacted surface protective film. These antiwear additives can drastically reduce wear with their concentration increasing, because the amount of additive adsorbed on metal sur(ace increases. But in the higher concentration region, the wear is increased by excessive and corrosive reaction of the metal surface with these additives. That is to say, there is an optimum concentration for minimum wear. The optimum concentration was different with the kinds of base oils and additives. Different polyolesters showed different optimum concentrations of the additive. The order of optimum concentration among the polyolesters was different with different phosphates. The order of the optimum concentration is shown that the effect of the concentration of additives on the antiwear performance. It can be explained by the interaction between additives and base oils using the solubility parameter.

• Tribology and Lubricants
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• 제4권1호
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• pp.43-55
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• 1988

A Study on the effect of the additives in lubricating oil was investigated on the basis of the thermal activated wear theory in terms of their wear behaviours, using four ballwear machine. The sample oils, which included diethyl-3, 5-di-t-butyi-4-hydroxy-benzyl phosphonate (DEP), ZDDP and TCP additives respectively, showed distinct wear characteristics depending upon the bulk oil temperature and the sliding velocity. The newly synthesized additive, viz., DEP showed excellent antiwear performance cornpared with the conventional additives, ZDDP and TCP. On the basis of the experimental results, it is reduced that the wear mechanism of the conventional additives, viz., ZDDP and TCP is the protective film formation and their antiwear capability is depending upon the shearing strength of the film formed. On the other hand, the new additive, DEP showed that the secondary activation energy was much eliminated and so, the thermal instability was reduced by the hydrogen scavenging reaction of the new additive, which was virtually an endothermic reaction process.In conclusion, a new concept of antiwear mechanism is estabilished and testified. And new chemical, which showed the function of hydrogen and free radical scavenging role, is synthesized and introduced as the new, highly antiwear effective lubricating oil additive.

• Tribology and Lubricants
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• 제10권4호
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• pp.59-68
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• 1994

This study is concerned with the change of physical and chemical properties of the used oil in gasoline and LPG engine. The used oils of engine were sampled from dynamometer and cars. The field tests of car were done in city and on highway. The properties of oil were TAN, TBN, visocity, oxidation, ZDTP depletion factor and etc. Also the relation between the chemical change and antiwear property was studied. From the study, it was shown that the decrease of antiwear property of used oil was depended on the changes of ZDTP depletion factor as well as TAN (total acid number). Also, it was found that the oil used by LPG car was deteriorated within the shortest distance among the other gasoline cars. The antiwear property of oil decreased as the running distance increased. The gasoline engine oil drove mainly on highway was the least deteriorate of properities for the same running distance.

• 한국자동차공학회논문집
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• 제4권1호
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• pp.1-15
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• 1996

This study is concerned with the property changes(chemical and mechanical) of the used oil in diesel engine, which were sampled from a test engine with dynamometer and various cars. The properties of oil are TAN, viscosity, oxidation, ZDTP depletion factor and etc. Also the relation between the change of chemical and antiwear property of used oil was strongly related to ZDTP depletion factor as wall as the change of TAN(total acid number), sulfation and pentan unsoluble contents which were reated to the formation of protect film in sliding area. The oil used in pick-up(small) truck engine was deteriorated within the shortest distance than that of other cars. The antiwear property of used oil was decreased sharply as the running distance were over 5,000km. The oil used to mini bus was the least to deteriorate of properities for the funning distance.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.341-342
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• 2002

Although vegetable oils provide good lubricity, they still need optimization by certain additive technology for practical applications. ZDTP improve antiwear properties of vegetable oils. However the additive performance depends on quality of the base Oil. Antioxidants were applied to prevent the auto-oxidation of vegetable oils. Good synergistic effect of anti-wear and antioxidant additives was confirmed.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.269-270
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• 2002

Antiwear(AW) properties of phoshphonic acid derivatives for trimethylolpropane (TMP) esters were investigated under boundary conditions. AW effect of dialkyl phosphonates depends on polarity of base fluid. They provide good AW performance in less polar TMP esters, whereas their AW effect is not sufficient in polar TMP esters. Amine salts of phosphonic acid were developed as new AW additiνe system for TMP esters. They provide excellent AW performance even in polar TMP esters.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.152-160
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• 1997

A diesel engine oil which was formulated and a commercial diesel engine oil (API CG4) made from same base oil were tested by car and analyzed of their physical, chemical and mechanical properties. The tested oil to be analyzed were sampled from engine every 1000 km until 8000 km and determined the kinematic viscosity, TAN, TBN, metal content in oil, additive depletion, antiwear property and IR analysis. From the study, both the tested oils were almost same properties for the change of TAN and TBN, but the change of kinematic viscosity of formulated oil was slightly higher than that of commercial oil. But the concentration of metal in the formulated oil, especially iron, were increased much less during test. The iron content of the commercial oil was increase rapidly from 7000 km while the formulated oil was still low. These results were conformed by the antiwear test by 4-ball wear test machine for the samples. Also for the commercial oil, the depletion factor of the Zn-DTP which was added as an antiwear property was not change any more after 7000 km. But the formulated oil was change continuously until 8000 km, which mean that the ability of wear protection of the sliding parts exists for the formulated oil. With the results which were analyzed of the properties of oils by field test, it was found that the commercial oil could be used only within 7000 km, but the formulated oil can use more than 8000 km without severe wear of the sliding parts in the diesel engine.

• 대한화학회지
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• 제23권1호
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• pp.52-58
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• 1979

금속 디알킬디티오인산염은 윤활유의 산화방지 및 내마모 첨가제로 널리 사용되고 있다. 특히 아연 DDTP가 윤활유 첨가제로서 가장 많이 사용되고 있다. 1차 및 2차 알킬기를 가진 아연, 납, 주석 및 코발트 디알킬디티오인산염을 각각 합성하였다. 합성된 각각의 금속 디알킬디티오인산염에 대하여 윤활유에서의 산화안정성, 열안정성, 금속부식성 및 내마모성을 실험검토하였다. 실험결과, 코발트 DDTP가 크롬합금강에 미치는 내마모성은 다른 화합물에 비하여 극히 우수하였으며 또한 코발트 DDTP는 일정온도 이상에서는 다갈색으로부터 청색으로 변하며 온도의 환원과 더불어 색상도 환원되는 특이한 색상의 온도 감도변화 성질이 있는 것을 알았다. 또한 모든 금속 디알킬디티오인산염은 일정 유효산 농도에 도달되어야만 윤활유의 산화 방지작용을 개시한다는 결과를 얻었다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.267-268
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• 2002

Engine testing of new low-sulfur, low-phosphorus anti wear components is expensive and time consuming so bench testing of potential candidates is highly desirable as a first step evaluation. Electrical contact resistance (ECR) has been shown to be a convenient method to assess antiwear film formation in a ball-on-flat bench wear test. Correlation of the bench test to fired engines was demonstrated for lubricants varying only in the type of detergent. Previous papers have examined film formation by one and two component formulations of zinc dialkyldithiophosphate (ZnDTP) and detergents. In this study, the ECR technique is systematically extended to formulations including ZnDTP, detergent, and dispersant. Both type and level of components are considered and the implications for engine performance are discussed.