Effects of rare earth treatment on tribological properties of self-lubricating spherical plain bearings

The effects of the rare earth treatment on the friction, wear, and bonding behavior of polymeric, self-lubricating spherical plain bearing materials were investigated. The materials of interest consisted of woven Kevlar (TM) and poly-tetrafluoroethylene (PTFE) fibers. An oscillating wear tester, operating at angles of ±10°, four different frequencies, and a constant load, was used to test assembled bearings at room temperature. Worn surface morphologies of the liners were investigated by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Compared with bearings without rare earth treatment, the bonding qualities between the binder and the surrounding steel housing, and the wear resistance of the treated bearings were both greatly improved. Contact surface morphology indicates that the treated bearing liners experienced only slight amounts of adhesive wear while those without the treatment seemed to wear more by abrasion. Overall, rare earth treatments served both to improve bonding quality of the bearing liner and improve their tribological properties.