ABSTRACTIn the present work, graphite (C) and polymethyl methacrylate (PMMA) were used as solid lubricants dispersed in lithium grease. Their effect on friction and wear of moving surfaces contaminated by solid contaminants in the cement plant is discussed. The tests were carried out at sliding velocity of 0.5 m/s and load of 10 N. The rotating specimens were greased before the test and further greasing was carried out every 30 second during the test. The test time was 5 minutes. The wear scar diameter was measured for the upper stationary pin by using an optical microscope with an accuracy of ± 1.0 µm. Experiments were carried out at 25 °C. Based on the experimental results , it was found that, graphite caused slight increase in friction and significant reduction of wear, while PMMA in most case causes decrease in friction and wear. Besides, wear and friction decreased with increasing oil content in grease, Wear and friction decreased with increasing PMMA. Graphite displayed low wear and The friction coefficient increases gradually when graphite content increased.
Mohamed et al. (Sat,) studied this question.