Modification of TiAlV Alloys with Hybrid Layers Containing Metallic Nanoparticles Obtained by the Sol–Gel Method: Surface and Structural Properties

The aim of the work was to obtain hybrid coatings containing silver, copper, and zinc nanoparticles on the TiAlV medical alloy via a sol–gel process. The developed layers were designed to bring about a bactericidal and fungicidal effect, as well as for protection against surgical scratches during the implantation of implants used in veterinary medicine. In this work, the authors focused on evaluating the microstructure (SEM + EDS); the structure (XRD, FTIR); and the surface properties, such as wettability, free surface energy, and roughness of layers with various concentrations of metallic nanoparticles (2 and 5 mol %). Our results confirmed that the sol–gel method enables the easy manufacturing of hybrid layers endowed with different porosity values as well as various shapes and sizes of metallic nanoparticles. A higher concentration of nanoparticles was observed on the surface containing 5 mol % of metallic salts. The highest degree of homogeneity was obtained for the layers containing silver nanoparticles. In addition, the silver nanoparticles were round and had the smallest dimensions, even below 20 nm. The FTIR and XRD structural studies confirmed the presence of an organosilicon matrix containing all three types of the metallic particles. We conclude that the higher concentration of nanoparticles influenced the alloy surface parameters.     

Excellent tribological behavior of hexadecylphosphonic acid films formed on titanium alloy

Titanium alloy(Ti6Al4V)surfaces are generally modified to achieve some specific surface properties to satisfy requirements of clinical medicine.In our work,hexadecylphosphonic acid(HDPA)films were successfully formed on Ti6Al4V and subsequently confirmed by X-ray photoelectron spectroscopy(XPS)and atomic force microscopy(AFM)measurements.The tribological properties of the HDPA-modified Ti6Al4V were investigated using a ball-on-disk tribometer with a linear reciprocating movement.Experimental results indicate that the HDPA-modified Ti6Al4V can maintain a low friction coefficient(approximately 0.06)for 4 h when sliding against polytetrafluoroethylene(PTFE)balls under a load of 0.8 N in comparison to bare Ti6Al4V(approximately 0.2);the friction coefficient of the HDPA-modified Ti6Al4V shows a 70%decline.In addition,the wear rate of PTFE balls sliding against bare Ti6Al4V was almost twenty times that of PTFE balls sliding against the HDPA-modified Ti6Al4V.Moreover,results of tribological experiments for different speeds(from 3 to 24 mm/s)and loads(from 0.8 to 3.2 N)proved that the HDPA-modified Ti6Al4V was not sensitive to both velocity and load.The friction coefficients were still low and stable even under a high load of 3.2 N or at a high speed of 24 mm/s.This indicates that this soft modification is an optional method of improving tribological properties of Ti6Al4V.