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Tudorache F.,Al. I. Cuza University | Petrila I.,Al. I. Cuza University | Popa P.D.,National Institute of Research and Development for Technical Physics IFT | Tascu S.,Al. I. Cuza University
Composites Part B: Engineering | Year: 2013

The purpose of this study was to analyze the methods and effects of introducing tungsten ions in a hexagonal barium ferrite structure by partial substitute of barium with tungsten. For this investigation we prepared a tungsten substitution on the barium hexaferrite Ba0.5W 0.5Fe12O19 using sol-gel self-combustion technology. The powder was treated for 30 min, without atmosphere precautions, at 850 C, 900 C, 950 C, 1000 C and 1050 C. Scanning electron microscopy has revealed the crystallite size and shape, and the X-ray diffraction was provided information related to the phase compositions. The investigation was focused on the variation of permittivity and electrical resistivity, in relation to the treatment temperature, frequency and humidity. We have also investigated the influence of thermal treatment on to Curie temperature and frequency characteristics of the relative permeability. Because barium-tungsten ferrite shows a porous structure, the measurements are strongly influenced by humidity conditions, and in this respect we analyzed the variations with humidity of permittivity and electrical resistivity. © 2013 Elsevier Ltd. Source

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