BLACKENING OF COPPER ALLOY BEARING CAUSED BY LUBRICATING OIL FOR AUTOMOBILE ENGINE
The phenomenon black-ized by the attack to the copper alloy bearing surface by engine oil may be revealed, depending on operation condition. It might be due to the progress of corrosion and deposition. In this study, the immersion examination at the temperature 150-200°C was carried out and the progress of blackening was evaluated through weight change measurement, analysis of the dissolution component in oil, and SEM observation. As a result, it was found that there is relationship between the decomposition temperatures of ZnDTP and blackening of bearing. It also turned out that much detergent additive leads to accelerate blackening of bearing.