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To achieve an efficient lubricated interface on titanium alloy (Ti6Al4V) alloy, polyelectrolyte multilayer (PEM) polymer coatings, based on poly(ethyleneimine)/poly(acrylic acid) (PEI/PAA), were fabricated on the surface of Ti6Al4V alloy substrates using the layer‐by‐layer (LbL) assembly technique. Their composition and morphology were confirmed by Fourier‐transform infrared/attenuated total reflectance (FTIR/ATR) spectroscopy, X‐ray photoelectron spectroscopy, and scanning electron microscopy. The tribological properties were investigated by a ball‐on‐disk rotating tribometer using deionized water, saline, and calf serum. The results exhibit that (PEI/PAA)*n coatings have the internal cross‐linked network and porous structure on the surface. The surface of PEI/PAA coatings‐modified Ti6Al4V shows the sufficient wettability. The polymer‐bearing interface of (PEI/PAA)*10 exhibits a low friction coefficient, 0.059, for 2 hr, and represents an 88% decline compared with bare Ti6Al4V. Moreover, the wear track on the polymer‐bearing interface is superlow. There is no obvious wear volume, which indicates effective wear resistance. The hydrated layer, the cross‐linked network structure, and the porous structure of PEM coatings are the main factors for efficient tribological properties. The multilayer PEI/PAA coating shows the potential uses of developing the lubricated‐bearing interface on Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]

With the purpose of achieving ultra-lubricated surface on Ti6Al4V alloy, porous TiO 2 layer, ultra-high molecular weight polyethylene (UHMWPE) film and hydrophilic 3-dimethyl(3-( N -methacrylamido)propyl)ammonium propane sulfonate (DMMPPS) polymer brushes were sequentially fabricated to form a composite coating. The change of surface morphology was investigated by Scanning Electron Microscope (SEM) during the preparation of composite coating. The composition and structure of modified surface were characterized by Energy Dispersive Spectrometry (EDS), X-ray Diffraction (XRD) and Fourier-transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR/ATR). The surface wettability was also studied to evaluate the hydrophilicity. Friction and wear properties of modified alloys sliding against stainless steel were preliminarily tested by a ball-on-disc tribometer in physiological saline. The results revealed that the composite coating with well hydrophilicity on Ti6Al4V alloy was successfully prepared. The modified surface presented an ultra-low friction coefficient at 0.02, and simultaneously indicated favorable wear resistance. This newly developed composite coating possessed potential to improve the tribological properties of Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the tribological properties of UHMWPE sliding against Ti6Al4V alloy, three different methods were applied to modified the alloys surface, namely two-step plasma immersion ion implantation, thermal oxidation (TO) and laser surface texturing (LST). Structure and wettability of surface modified titanium alloy were investigated. Friction and wear properties of UHMWPE sliding against modified alloys were tested by a pin-on-disc tribometer under distilled water and bovine serum respectively. The results showed that a graded titanium oxide–titanium nitride film and a titanium oxide film formed separately after being treated by ion implantation and TO, thus contributing to the improvement of wettability of alloy surfaces. The friction coefficients of modified Ti6Al4V alloys decreased obviously, especially for the TO-treated one, which reached as low as 0.015. The wear rate of UHMWPE was reduced and the lowest wear rate was obtained when sliding against the ion implanted one. Almost no notable wear features presented on the titanium alloy treated by ion implantation. [Copyright &y& Elsevier]