Tribological Characterization of a Novel Ceramic–Epoxy–Kevlar Composite

This work aims to explore the effect of side load and rotational speed on the tribological behavior of a novel ceramic–epoxy composite in Kevlar matrix casing lining that is in contact with a rotating drillpipe tool joint (DP-TJ) coated with the same composite. Three rotational speeds (65, 115, and 154 rpm) and three side loads (500, 700, and 1000 N) were considered under water-based mud (WBM) lubrication. Wear depths, volumes, and specific casing wear rates (K) were determined for each combination of speed and load. The wear depth and K were found to increase with an increasing applied side load. However, the specific casing wear rate at the rotational speed of 115 rpm was found to be the lowest among the three speeds. This is mainly due to a probable lubrication regime change from boundary lubrication at 65 rpm to hydrodynamic lubrication with a thick lubricant film at 115 rpm. The digital microscope images were used to determine the wear mechanism, showing that at low speeds, the main mechanism was abrasive wear, but the increase in the speed brought about more adhesive wear. In contrast, the change in the side load does not affect the wear mechanism of the casing. Scanning electron microscopy and energy-dispersive spectroscopy (EDS) were used to analyze the surface and composition of the novel material before and after the wear tests.