Abstract
Lubricating oil and hydraulic fluid deteriorate for the oxidation and contaminations from outside. The oil oxidation products repeat polycondensation and form oil-sludge including contaminations. But, the general oil analysis cannot analyze the situation of oil-sludge generation definitely. In this study, it was clarified that the judging oil-sludge generation was possible by using the separation oil-sludge from base oil by centrifugation and the comparison of laser transmittance before and after centrifugation.
