• T S Sampath Kumar

      Articles written in Bulletin of Materials Science

    • Synthesis and characterization of bioactive hydroxyapatite/fluoroapatite solid solutions using corals

      T S Sampath Kumar M Sivakumar N Prasanth Kumar K Senthamil Selvi K Panduranga Rao

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      Hydroxyapatite/fluoropatite solid solutions were prepared by two different methods using Indian coast corals. In the ‘low temperature method’ a known volume (50%) of hydrofluoric acid was added to the coral and an exchange reaction with diammonium phosphate was carried out to form apatite at 250°C under hydrothermal conditions. The coralline derived hydroxyapatite by the above method was reacted with 50 mol% sodium fluoride at 900°C in the ‘high temperature method’. The X-ray powder diffraction, infrared spectroscopy and thermal analysis techniques were employed to characterize the fluorination of the hydroxyapatite.In vitro solubility study in phosphate buffer solution of pH 7·2 indicate the stability of the apatites. The low temperature method of fluorination seems to be advantageous due to betterin vitro stability and absence of impurity phases.

    • Phase instabilities during Ti-nitride precipitation in nitrogen implanted Ti-6AI-4V alloy

      N Rajan T S Sampath Kumar K G M Nair K Krishan

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      Grazing incidence X-ray diffraction, performed on a 70 keV nitrogen implanted Ti-6Al-4V system, reveals phase instabilities, during the course of nitride formation. With the build up of unbound N atom concentration, for a dose of 1×1016 ions/cm2, the surface region becomesα-rich, whereas, on precipitation of Ti-nitrides at a high dose of 1×1017 ions/cm2, theβ-Ti phase reappears, at the surface and beyond the implanted zone. The low concentration of V and the strain in the nitrided zone, have led to radiation induced martensitic transformation of theβ-Ti phase.

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    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

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