Preparation and properties of poly-(p)-oxybenzoyl/aluminum bronze composite coating by atmosphere plasma spraying

Poly-(p)-oxybenzoyl/aluminum bronze (denoted as POB/CuAl) composite coating was deposited as a candidate of lead-free bearing surface on a steel substrate by plasma spraying. The composition, microstructure, and chemical feature of the sprayed POB/CuAl composite coating were analyzed by scanning electron microscopy, energy dispersive spectrometry, and Raman spectroscopy. And the friction and wear behavior of the POB/CuAl composite coating was evaluated and compared with that of pure aluminum bronze coating and AISI-E52100 bearing steel on a ball-on-disc reciprocal tribometer. It was found that plasma sprayed POB/CuAl composite coating possesses a low and stable friction coefficient in combination with greatly reduced wear rate as compared with pure CuAl coating and AISI-E52100 bearing steel. More importantly, the POB/CuAl composite coating causes minimum damage to its frictional counterpart, which is significant for its application as a lead-free bearing surface. This is because, after the short running-in period under dry sliding condition, the POB/CuAl composite coating forms an “adaptive” frictional surface in which the well accommodated POB particles can effectively dissipate the input frictional energy through elastic deformation and recovery and, consequently, greatly alleviate the abrasive wear and splat delamination of the composite coating.