Features of Composite Layers Created Using an Aqueous Suspension of a Fluoropolymer

Organic-Inorganic Biocompatible Coatings for Temporary and Permanent Metal Implants

The general trend of increasing life expectancy will consistently drive the demand for orthopedic prostheses. In addition to the elderly, the younger population is also in urgent need of orthopedic devices, as bone fractures are a relatively common injury type; it is important to treat the patient quickly, painlessly, and eliminate further health complications. In the field of traumatology and orthopedics, metals and their alloys are currently the most commonly used materials. In this context, numerous scientists are engaged in the search for new implant materials and coatings. Among the various coating techniques, plasma electrolytic oxidation (PEO) (or micro-arc oxidation-MAO) occupy a distinct position. This method offers a cost-effective and environmentally friendly approach to modification of metal surfaces. PEO can effectively form porous, corrosion-resistant, and bioactive coatings on light alloys. The porous oxide surface structure welcomes organic molecules that can significantly enhance the corrosion resistance of the implant and improve the biological response of the body. The review considers the most crucial aspects of new combined PEO-organic coatings on metal implants, in terms of their potential for implantation, corrosion resistance, and biological activity in vitro and in vivo.

The effect of silica NPs incorporation on protective properties of oxide layers formed by PEO on Mg97Y2Zn1 alloy with LPSO-phase

The inherited chemical inhomogeneity in oxide layers obtained by plasma electrolytic oxidation (PEO) on the magnesium alloy Mg97Y2Zn1 is associated to long-period stacking-ordered (LPSO) phase present in the treated alloy. This heterogeneity results in decrease of corrosion resistance and adhesion strength. The problem was solved by adding silica nanoparticles (NPs) into the electrolyte under PEO. According to the model developed, NPs which are harder than the oxide layer and being electrically charged, can be accelerated by an electric field and penetrate deep into the layer. The near-surface incorporation of NPs results in branching of the local breakdowns of vapor-gas bubbles that leads to an increase of the volumes of oxide layer and improvement of its properties.

Morphological analysis of plasma electrolytic oxidation coatings formed on Ti6Al4V alloys manufactured by electron beam powder bed fusion

This study investigates and compares plasma electrolytic oxidation (PEO) coatings produced on wrought Ti6Al4V alloy substrates with those resulting from electron beam powder bed fusion (PBF-EB). For a duration of 1000 s, a phosphate/silicate electrolyte with a current density of 50 A/cm2 was employed to fabricate the coatings. Surface and polished cross-sections of the coated specimens underwent SEM and X-ray diffraction (XRD) analyses. The obtained coatings exhibit differences of up to approximately 18% in thickness and formation, as well as in their anatase phase. The anatase phase is present at a level of 54.09% in the substrates processed by PBF-EB and 38.54% in wrought substrates. After 1000 s of PEO, the coatings formed on the wrought substrates exhibited higher porosity and larger pores (>1 μm) compared to those produced on the PBF-EB specimens. The PBF-EB coatings had lower porosity because they contained fewer pores larger than 1 μm. The findings imply that the unique microstructural arrangement of PBF-EB-produced additively made Ti6Al4V materials plays a significant impact in the development and morphological properties of PEO oxide coatings.