Filters

2019 - 201912020 - 20232

More filters

2021 - 20243
Reset filters

Settings

Author: Calin, Mariana × End date: 2023 × DDC: 660 × Has files: Yes × WGL Institute: IFWD ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    The influence of partial replacement of Cu with Ga on the corrosion behavior of Ti40Zr10Cu36PD14 metallic glasses
    (Bristol : IOP Publishing, 2019) Wei, Qi; Gostin, Petre Flaviu; Addison, Owen; Reed, Daniel; Calin, Mariana; Bera, Supriya; Ramasamy, Parthiban; Davenport, Alison
    TiZrCuPdGa metallic glasses are under consideration for small dental biomedical implants. There is interest in replacing some of the Cu with Ga to improve the glass-forming ability and biocompatibility. Ti40Zr10Cu36-xPd14Gax (x = 0, 1, 2, 4, 8 and 10 at.%) metallic glasses in rod and ribbon forms were fabricated by mould casting and melt spinning, respectively, and electrochemically tested in a 0.9wt.% NaCl (0.154 M) solution. It has been shown that for both rod and ribbon samples Ga levels up to 8% have no significant effect on passive current density, pitting potential or cathodic reactivity in 0.9% NaCl at 37°C. Different pitting potential and corrosion potential values were found when ribbon and rod samples of the same composition were compared for all compositions apart from the one containing the highest Ga level (10%). This was attributed to structural relaxation occurring as a result of the slower cooling rates during casting rods compared with melt-spinning ribbons. Substitution of Ga for Cu in these metallic glasses therefore expected to have no significant effect on corrosion susceptibility. © The Author(s) 2019.
  • Thumbnail Image
    Item
    Designing Gallium-Containing Hydroxyapatite Coatings on Low Modulus Beta Ti-45Nb Alloy
    (Basel : MDPI, 2023) Vishnu, Jithin; Voss, Andrea; Hoffmann, Volker; Alberta, Ludovico Andrea; Akman, Adnan; Shankar, Balakrishnan; Gebert, Annett; Calin, Mariana
    Low-modulus β-type Ti-45Nb alloy is a promising implant material due to its good mechanical biocompatibility, non-toxicity, and outstanding corrosion resistance. Its excellent chemical stability brings new challenges to chemical surface modification treatments, which are indispensable for both osteogenesis and antibacterial performance. Coatings containing metal ions as anti-microbial agents can be an effective way to reduce implant-associated infections caused by bacterial biofilm. Gallium ion (Ga3+) has the potential to reduce bacterial viability and biofilm formation on implant surfaces. In this study, a novel two-step process has been proposed for Ga3+ incorporation in hydroxyapatite (HAP) to develop bioactive and antibacterial surfaces on Ti-45Nb alloy. For the generation of bioactive surface states, HAP electrodeposition was conducted, followed by wet chemical immersion treatments in gallium nitrate (1 mM). Different buffers such as phosphate, sodium bicarbonate, ammonium acetate, and citrate were added to the solution to maintain a pH value in the range of 6.5–6.9. Coating morphology and HAP phases were retained after treatment with gallium nitrate, and Ga3+ ion presence on the surface up to 1 wt.% was confirmed. Combining Ga and HAP shows great promise to enable the local delivery of Ga3+ ions and consequent antibacterial protection during bone regeneration, without using growth factors or antibiotics.
  • Thumbnail Image
    Item
    Tribocorrosion behavior of β-type Ti-Nb-Ga alloys in a physiological solution
    (Amsterdam [u.a.] : Elsevier Science, 2023) Alberta, Ludovico Andrea; Vishnu, Jithin; Douest, Yohan; Perrin, Kevin; Trunfio-Sfarghiu, Ana-Maria; Courtois, Nicolas; Gebert, Annett; Ter-Ovanessian, Benoit; Calin, Mariana
    Tribo-electrochemical behavior in physiological solution of two β-type (100-x)(Ti-45Nb)-xGa (x = 4, 8 wt%) alloys, alongside β-Ti-45Nb and medical grade Ti-6Al-4V ELI, was investigated. Microstructure and mechanical behavior were evaluated by X-ray diffraction, microhardness and ultrasonic method. Tribocorrosion tests (open circuit potential, anodic potentiostatic tests) were performed using a reciprocating pin-on-disk tribometer under constant load. Degradation mechanisms are similar for the alloys: plastic deformation, delamination, abrasive and adhesive wear. Among the β-Ti-Nb alloys, an improved wear resistance with lower damage was remarked for β-92(Ti-45Nb)-8Ga alloy, attributed to increased microhardness. Content of Ga3+ ions released in the test solutions were found to be in very low amounts (few ppb). Addition of Ga to Ti-45Nb resulted in improved corrosion resistance under mechanical loading.