Tribotechnical Diagnostics of Used Oils II. Methods of Assessment of Physicochemical Properties of Oils
Faculty of Production Technologies, Technical University, Košice, Slovak Republic
Methods used in tribotechnical diagnostics of military airplane engines based on evaluation of physicochemical characteristics of the used oils are reviewed. Their kinematic viscosity was determined at 40 °C and 100 °C using an automatic viscometer. An increase in viscosity may indicate contamination of oil with impurities or water due to degradation or vaporization of volatiles. A decrease in viscosity indicates contamination of oil with fuel. The total acid number of oil was determined by titration with KOH. Water was determined by Karl Fischer titration. The flash point was determined by the Cleveland open cup method. Applications of the described methods are shown on two examples.
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