VARIATION WITH TEMPERATURE OF SURFACE TENSlON OF LUBRICATING OILS

摘要

Surface-tension measurements from room temperature to l8o C of a series of aeronautical lubricating oils and a few liquids of associated interest are reported. The measurements were obtained from a Du Nouy tensiometer and corrected according to the theory of Harkins and Jordan. The critical temperatures of the liquids are calculated and thus a general classification of existing oils into three groups is provided. The effect of use or exposure to high temperatures is to leave the relation between surface tension and temperature virtually unchanged, unless the use has been excessively prolonged, when decompo-sition begins and the surface tension is lowered.