Articles written in Bulletin of Materials Science

    • Development of calcium phosphate based bioceramics

      Amit Sinha A Ingle K R Munim S N Vaidya B P Sharma A N Bhisey

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      Two bioceramics (Ca–P–O glass and A–W glass ceramic) were produced using conventional methods of ceramic technology. X-ray powder diffraction patterns were used for identifying the phases and 3-point bend test was carried out for the determination of fracture strength of the bioceramics. Biocompatibility of both ceramics was evaluated using animal model experiments. Histological studies showed that A–W glass ceramic implanted in the tibia of rat formed an intimate contact with newly grown bone and provided enough strength to the bone to bear the animal weight. Implants made of Ca–P–O glass was almost fully resorbed and was replaced by new bone. The implants made of both the bioceramics were biocompatible and did not exhibit any kind of adverse effect to the surrounding tissues.

    • Preparation of silver powder through glycerol process

      Amit Sinha B P Sharma

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      High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a temperature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders prepared through this process were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The powders were well crystalline and contained oxygen, carbon and hydrogen as impurities. Overall purity was better than 99.9%. The yield of silver powder was better than 99%.

    • Effect of processing route on the properties of LSCF-based composite cathode for IT-SOFC


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      A novel processing technique was developed to produce an in-situ nano-composite powder based on La$_{0.6}$Sr$_{0.4}$Co$_{0.2}$Fe$_{0.8}$O$_{3-\delta}$ (LSCF6428) and Gd$_{0.1}$Ce$_{0.9}$O$_{1.95}$ (GDC10) for application as cathode material in intermediate temperature solid oxide fuel cells (IT-SOFC). The nano-composite powder was produced using glycine-nitrate solution combustion technique starting from nitrates of six metal ions. The synthesized powder was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), particle size and BET surface area analyses. XRD analysis of as-produced nano-composite powder confirmed the formation of desired phases right after combustion synthesis. The structural parameters of different phases present in the powders were estimated through Rietveld refinement of XRD data. Tocompare the electrical properties of nano-composite cathode powder produced through the present method, nano-powders of GDC10 and LSCF6428 were individually produced through glycine nitrate process and subsequently mixed through solidstate technique and characterized for functional properties. Using this in-situ nano-composite material, lower polarization resistance was achieved as compared to the LSCF–GDC composite produced from mechanical mixtures of nano-powders of GDC10 and LSCF6428 when used as cathode in GDC10 electrolyte-based symmetrical cell. The effects of cathode layer thickness and electrode firing temperature on the cathodic polarization resistance were studied using in-situ nano-composite cathode powder.

    • Synthesis and characterization of gadolinium-doped ceria and barium cerate-based composite electrolyte material for IT-SOFC


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      A nanocomposite, containing gadolinium-doped ceria (GDC, Ce$_{0.85}$Gd$_{0.15}$O$_{1.925}$) and 10 mol% gadoliniumdopedbarium cerate (BGC, BaCe$_{0.85}$Gd$_{0.15}$O$_{2.925}$), was developed as an electrolyte material for intermediate temperature solid oxide fuel cell. The composite powder was synthesized through an auto-combustion process that yielded the desired phases right after combustion. The powder was characterized using X-ray diffraction, particle size analysis, Brunauer–Emmett–Teller surface area analysis and transmission electron microscopy. The electrical properties of the composite electrolyte were characterized by electrochemical impedance spectroscopy under air as a function of temperature. The effect of second phase on total conductivity and activation energy of the composite material was compared with that of GDC of similar composition. For this, GDC (Ce$_{0.85}$Gd$_{0.15}$O$_{1.925}$) powder was produced using a similar processing technique. The microstructural characterization of GDC and GDC–10BGC composite materials was studied through scanning electron microscopy. The electrochemical properties of planar cell, using GDC–10BGC as electrolyte and employing Ni–(GDC–10BGC) and La$_{0.6}$Sr$_{0.4}$Co$_{0.2}$Fe$_{0.8}$O$_{3-\delta}$-based anode and cathode materials, were investigated.

    • Phase evolution and conductivity study of doped gadolinium-based perovskite oxides


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      The phase evolution and electrical conductivity of strontium-doped gadolinium aluminate (GdAlO$_3$) based perovskite oxides were investigated. The strontium-doped compositions of GdAlO$_3$ were prepared through the citrate gelprocess. Analyses of the phases in the Gd$_{1–x}$Sr$_x$AlO$_{3–{\delta}}$ system were carried out using X-ray diffraction. The morphology of the calcined powders was studied through scanning electron microscopy. The strontium-doped GdAlO$_3$ powdersobtained after calcination at 1000°C was found to be porous agglomerate composed of nanocrystalline grains. The electrical conductivity of Gd$_{1–x}$Sr$_x$AlO$_{3–{\delta}}$ (x = 0.02–0.14) was measured using ac impedance spectroscopy as a function of temperature ranging from 300 to 1000°C under air. The solid solubility of strontium in GdAlO$_3$ was found to be around 8 mol%. The undissolved strontium precipitated in the form of SrGd$_2$Al$_2$O$_7$ phase. The total electrical conductivity of Srdoped GdAlO$_3$ increased with increasing amounts of strontium up to 6 mol% doping.

  • Bulletin of Materials Science | News

    • 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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