Development of Ti-Mo alloys for biomedical applications: Microstructure and electrochemical characterization

Ti-Mo alloys from 4 to 20 Mo wt.% were arc-melted. Their compositions and surfaces were analyzed by EDX, XRF and SEM. The Mo mapping shows a homogeneous distribution for all alloys. The XRD analysis showed that the crystal structure of the alloys is sensitive to the Mo concentration; a mixture of the hexagonal alpha' and orthorhombic alpha '' phases was observed for the Ti-4Mo alloy, and the alpha '' phase is observed almost exclusively when the concentration of Mo added to the Ti reaches 6%. A significant retention of the beta phase is observed for the alloy containing 10% Mo, while at higher Mo concentrations (15% and 20%), retention of phase beta is only verified. Preliminary electrochemical studies have indicated a valve-metal behavior and good corrosion resistance in aerated Ringer solution for all alloys. (c) 2006 Published by Elsevier B.V.45272773

Photo-Electrochemical Investigation of Anodic Oxide Films on cast Ti-Mo Alloys. I. Anodic behaviour and effect of Alloy Composition

The anodic behaviour of cast Ti–Mo alloys, having different Mo contents (6–20 wt.%), was investigated in acidic and neutral aerated aqueous solutions. All sample showed a valve-metal behaviour, owing to formation and thickening of barrier-type anodic oxides displaying interference colours. Growth kinetics of passive films is influenced by both anodizing electrolyte and composition of the starting alloy. This last parameter was found to change also the solid-state properties of the films, explored by photoelectrochemical and impedance spectroscopy experiments. Thicker films (Uf = 8 V/MSE) grown on alloys richer in Mo showed more resistive character and a photocurrent sign inversion under negative bias, that revealed an insulating character, whereas corresponding films grown on alloys with lower Mo content, as well as thinner films, behaved as n-type semiconductors. Results are discussed in terms of formation of a mixed Ti–Mo oxide phase

Hydroxyapatite deposition study through polymeric process on commercially pure Ti surfaces modified by laser beam irradiation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Many techniques have been used to coat metallic substrate with bioceramics. The aim of this study was to study the physical-chemical characteristics of polyvinylidene fluoride (alpha-PVDF)/hydroxyapatite (HA) composite coating, obtained by casting method, on commercially pure titanium (alpha-CP Ti) substrate surface modified by laser beam irradiation. The preparation of coating was done for mixing alpha-PVDF pellets shape dissolved in dimethylacetamide (DMA) with HA/DMA emulsion. The mixture was poured onto the alpha-CP Ti sample and left to dry in an oven. CP Ti plates were coated with alpha-PVDF/HA composite film, in proportions of 100/00 and 60/40 in weight, and characterized by particle size analysis, scanning electron microscopy, energy dispersive spectroscopy (EDS), X-ray diffractometry, thickness measurement and contact angle. Uniform coating with a small thickness variation along the coated surface was successfully obtained.441540564061Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Adhesion strength characterization of PVDF/HA coating on cp Ti surface modified by laser beam irradiation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Up to the moment, there is no standardized test for measuring the adhesion strength of polymeric coatings on titanium substrate modified by laser beam irradiation. The present work aimed to assess the adhesion strength of polyvinylidene fluoride (alpha-PVDF)/hydroxyapatite (HA) composite coating on commercially pure titanium (alpha-cp Ti) substrate surface modified by laser beam irradiation, using the three-point bending test. The preparation of coating was carried out by mixing alpha-PVDF pellets dissolved in dimethylacetamide (DMA) with HA/DMA emulsion. The mixture was poured onto the alpha-cp Ti sample and left to dry in an oven. Commercially pure titanium plates were coated with alpha-PVDF/HA composite film, in proportions of 100/00 (PVDF) and 60/40 (PVDF/HA) in weight. The Ti-PVDF/HA samples were subjected to the three-point bending test and analyzed by scanning electron microscopy. According to the results, PVDF and PVDF/HA coatings showed a good adhesion strength on alpha-cp Ti surface, since no detachment was observed. (C) 2012 Elsevier B.V. All rights reserved.258241011010114Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES