Improvements in tribological and anticorrosion performance of porous Ti-6Al-4V via PEO coating

Abstract

Medical implants manufactured using biomaterial Ti-6Al-4V exhibit some disadvantages. Its higher elastic modulus than that of natural bone can cause stress shielding problems. This can be avoided using Ti-6Al-4V with pores in the implant structure. However, poor corrosion and tribocorrosion behaviors are yielded because of the large area exposed to the medium. To mitigate both issues, coating technologies can be applied. The plasma electrolytic oxidation (PEO) process is a cost-effective process that has been used successfully in nonporous Ti alloys. In this study, two PEO coatings with different amounts of Ca/P are used. However, reports regarding their application in porous materials are scarce. The effects of PEO treatments on corrosion and tribocorrosion in Ti-6Al-4V powder metallurgy are analyzed herein. The porous materials provide an efficient surface for PEO coatings, as demonstrated via scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the porosity of the substrates improved the adherence of the coatings. The corrosion resistance measured via electrochemical impedance spectroscopy confirmed the beneficial effect of the coatings, particularly for long exposure time. The lower roughness, small pore size, and more compact film observed in the PEO-Ca/P sample resulted in favorable tribological and corrosion properties.

Coatings and Surface Modification of Alloys for Tribo-Corrosion Applications

“…Apart from the comprehensive studies by Alves, other researchers have also explored the techniques of PEO and MAO on Ti-6Al-4V substrates. For example, Garcia-Cabezón in Spain demonstrated that PEO-Ca/P coatings on these substrates offer enhanced performance due to a higher rutile-to-anatase ratio and smoother surface [175]. Similarly, in China, You Zuo's research indicated that increasing the voltage in MAO coatings adjusts the rutile-to-anatase ratio [176] and incorporating graphene oxide particles notably improves tribocorrosion resistance [177].…”

Elevated-temperature wear behavior of Ti6Al4V alloy: microstructural evolution and properties change in subsurfaces and mild-severe wear transition

“…Despite all this, Ti6Al4V alloy is still utilized to make wear components in chemical, aviation and automotive sectors, such as gear, spherical plain bearing, engine valve, and engine connection rod and turbine disk [4]. In recent years, a number of surface coating and modification techniques, including laser surface treatment, carburizing, nitriding, ion implantation and so on, have been employed to improve its wear properties, and some of them have achieved good results [5][6][7][8][9]. These achievements provide Ti6Al4V alloy with a great prospect for wider tribological applications.…”

Synergistic Effect of F−and Persulfate in Efficient Titanium Alloy Chemical Mechanical Polishing

“…1,2 For instance, Ti-6Al-4V (TC4) alloy has been applied in artificial implants, such as prostheses, fracture fixation and cardiovascular devices, due to its superior biocompatibility, strength-weight ratio and corrosion resistance. [3][4][5] Artificial implants require excellent surface quality to enhance the biocompatibility and to extend the service life. 6,7 Conventionally, artificial implants are fabricated by the traditional machining techniques, such as turning, milling and grinding.…”