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    • Keywords


      HVOF; TiO2; phase transformation; nanostructure coating.

    • Abstract


      A liquid fuel high velocity oxy-fuel (HVOF) thermal spray process has been used to deposit TiO2 nanostructured coatings utilizing a commercially available nanopowder as the feedstock. The coatings were characterized by means of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM), respectively. Photocatalytic activity was evaluated as a rate constant of decomposition reaction of methylene blue (MB) determined from the changes of relative concentration of MB with UV irradiation time. The results indicate that the sprayed TiO2 coatings were composed of both TiO2 phases viz. anatase and rutile, with different phase contents and crystallite sizes. A high anatase content of 80% by volume was achieved at 0.00015, fuel-to-oxygen ratio with nanostructure coating by grain size smaller than feedstock powder. Photocatalytic activity evaluation results indicated that all the TiO2 coatings are effective to degradation MB under UV radiation and their activities differ in different spray conditions. It is found that fuel flow rate strongly influenced on phase transformation of anatase to rutile and by optimizing the rate which can promote structural transformation and grain coarsening in coating and improving photocatalytic activity.

    • Author Affiliations


      Maryamossadat Bozorgtabar1 Mehdi Salehi2 Mohammadreza Rahimipour3 Mohammadreza Jafarpour4

      1. Islamic Azad University-Majlesi Branch, Majlesi New Town, Isfahan, Iran
      2. Department of Materials Engineering, Isfahan University of Technology, Isfahan 84154, Iran
      3. Materials and Energy Research Centre, P. O. Box 14155-4777, Tehran, Iran
      4. Mobarakeh Steel Company, P. O. Box 84815-161, Isfahan, Iran
    • Dates

  • Bulletin of Materials Science | News

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      Posted on July 25, 2019

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