Surface engineered titanium alloys for biomedical devices

Investigation of hydroxyapatite (HAP) containing coating on grade 2 titanium alloy prepared by plasma electrolytic oxidation (PEO) at low voltage

“…In this second case, specific compounds should be added into the electrolyte, in particular Ca and P compounds as deeply studied by Molaei et al [36]. However, in literature, as reported for example in the comprehensive review work of Pesode et al [37] or in the book [38], PEO coatings on Ti alloys are produced at high voltages, between 500 and 800 V, with very high energy consumption. Studies about the use of lower voltages during PEO process were already performed on Al alloys [39,40], whereas the production of energy efficient PEO coatings on Ti alloys is not yet reported in literature.…”

Plasma Electrolytic Oxidation (PEO) Layers from Silicate/Phosphate Baths on Ti-6Al-4V for Biomedical Components: Influence of Deposition Conditions and Surface Finishing on Dry Sliding Behaviour

“…The abrasive blasting post-treatment mentioned in Table 1 was carried out by using spheroidal glass beads (100 ± 10 µm average diameter, average elemental composition measured by EDS, wt.%: Si 30, O 52, Na 9, Ca 6, Mg 2, Al 1) as abrasive medium in an industrial blasting device used for implantable metallic components. In fact, a low surface roughness is required in tribological contacts, so as to limit the production of hard wear debris which also adversely affect the biological response [3]. Therefore, all the PEO-treated specimens were abrasive-blasted, with the exception of sample B, used only as a reference: by comparing it to sample A, obtained in the same treatment conditions, it is possible to assess the influence of the abrasive blasting process on microstructure and tribological behaviour of PEO layers.…”

“…Therefore, even though Ti-6Al-4V shows low abrasion resistance and undergoes severe adhesive wear, it provides an important alternative to Co-based alloys: Chen and Thouas [1] demonstrated that Co-based alloys are affected by other limitations due to adverse stress shielding effects as well as to toxic metal ions release. From a metal toxicity point of view, also alloying elements such as Al and V in Ti-6Al-4V may be associated to long term health problems and newly developed, Al-and V-free alloys were proposed for the biomedical field (e.g., Ti-13Nb-13Zr) [3], however Ti-6Al-4V still covers a large number of applications, considering also non-permanent components such as intramedullary nails and screws.…”

“…In order to compensate for possible metal release and, most of all, for the unsatisfactory tribological behaviour of Ti-6Al-4V in implantable biomedical devices, Huang et al [3] proposed several surface engineering techniques: oxidation produced by either heat treatment or electrolytic anodizing is one of the most popular but also the vapour-phase deposition of carbon-based films (DLC-type) and thermal spraying of hydroxyapatite have been widely investigated. Among oxidation techniques, Plasma Electrolytic Oxidation (PEO), sometimes also named Anodic Spark Deposition (ASD) or Micro-Arc oxidation (MAO), is attracting a significant research and development interest, due to its ability to enhance tribological substrate properties of light alloy and valve metals, forming an effective ion release barrier.…”

Microstructural Characterization of Pure Titanium Treated by Laser Surface Treatment Under Different Processing Parameters

“…However, the problems in long-term use of Ti alloys as medical implant are the bioinertness and poor adhesion [3,4]. It is worth noting that surface engineering aims to tailor the microstructure and composition of the near-surface region, improving mechanical properties without affecting the substructure of bulk material [5,6]. Thus, surface engineering can offer significant potential for improving near-surface properties of Ti and its alloys.…”