Effects of the Nano-Diamond Additives on the Tribological Performance Improvement of Lubricating Grease

Ball screw is a very important element in precision machine industry. It has a lot of superior characteristics such as low friction coefficient, long life, high positioning accuracy and as well as converting rotational motion to linear motion. Therefore, the lubricant used in the ball screw should be low friction and wear in order to meet the aims of the above mentioned properties. The ultra-dispersed nanodiamond (UDD) is dispersed in the dispersant. The UDD is served as an extreme pressure additive in the test grease that is applied to the ball screw. Four-ball extreme pressure tests and bearing life tests were conducted in this study to evaluate the extreme pressure performance and durability enhancement of the test grease. The four-ball test results showed that the optimum selection of the dispersant category, UDD mean particle diameter and concentration added to the test grease provided by the cooperated ball screw manufacturer in this study are OLA, 200 nm and 100 ppm, respectively.