Enhancing friction and vibration reduction properties of a polymer using h-BN particles

Abstract

The unstable contact state of the water-lubricated bearings can induce severe friction and vibration behavior in extreme conditions, posing a threat to the reliability and stability of ship propulsion systems. Enhancing the self-lubrication and reducing the frictional excitation forces are crucial for eliminating or suppressing the friction-induced vibration behavior during the frictional processes. This study developed a new composite material by incorporating hexagonal boron nitride (h-BN) particles into a thermoplastic polyurethane (TPU) matrix. Frictional vibration experiments were conducted to investigate the influence of h-BN particles on frictional vibration behavior. Comprehensive evaluations were performed on the coefficient of friction (COF), wear mass loss, vibration behavior, morphology, and element distribution to elucidate the influences of h-BN particles. The findings demonstrated that adding h-BN imparted excellent self-lubricating properties to TPU and significantly reduced the deformation on the worn surface. It effectively reduced COF behavior as well as its fluctuation amplitude, thereby enhancing the wear resistance and attenuating the vibration behaviors of the friction system. TPU modified by 6 wt.% h-BN exhibited the lowest COF with minimal fluctuation amplitude and the best vibration reduction properties, particularly at higher frequencies. The knowledge obtained herein will aid in a better understanding of the influences of h-BN on friction and vibration reduction, facilitating the design of water-lubricated TPU matrix composite bearings with promising self-lubrication and frictional vibration reduction performances.