CORROSION RESISTANCE OF AS-PLATED AND HEAT-TREATED ELECTROLESS DUBLEX Ni-P/Ni-B-W COATINGS


Yuksel B., Erdogan G., Bastan F. E. , Yildiz R. A.

MATERIALI IN TEHNOLOGIJE, vol.51, no.5, pp.837-842, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 51 Issue: 5
  • Publication Date: 2017
  • Doi Number: 10.17222/mit.2016.304
  • Title of Journal : MATERIALI IN TEHNOLOGIJE
  • Page Numbers: pp.837-842

Abstract

In this study, Ni-P/Ni-B-W dublex coatings were deposited on carbon steel substrates (AISI 1020) using the electroless plating process and their microstructure and corrosion properties were systematically evaluated based on different heat-treatment temperatures. Both, the surface morphology and cross-sectional morphology of the Ni-P/Ni-B-W coatings were studied using a scanning electron microscope (SEM), while X-ray diffraction (XRD) was applied for examining the structural modifications. The amorphous coating began to crystallize at a heat-treatment temperature of 350 °C. Potentiodynamic polarization measurements were carried out in an aqueous medium containing 3.5 % NaCl for evaluating the corrosion resistance of as-plated and heat-treated dublex coatings. The corrosion potentials of dublex coatings were observed to shift toward more positive values with increased heat-treatment temperatures. Depending on the heat-treatment temperature, it was identified that the crystallized dublex coatings generally had better corrosion resistance than the amorphous coating.

In this study, Ni-P/Ni-B-W dublex coatings were deposited on carbon steel substrates (AISI 1020) using the electroless plating process and their microstructure and corrosion properties were systematically evaluated based on different heat-treatment temperatures. Both, the surface morphology and cross-sectional morphology of the Ni-P/Ni-B-W coatings were studied using a scanning electron microscope (SEM), while X-ray diffraction (XRD) was applied for examining the structural modifications. The amorphous coating began to crystallize at a heat-treatment temperature of 350 degrees C. Potentiodynamic polarization measurements were carried out in an aqueous medium containing 3.5 % NaCl for evaluating the corrosion resistance of as-plated and heat-treated dublex coatings. The corrosion potentials of dublex coatings were observed to shift toward more positive values with increased heat-treatment temperatures. Depending on the heat-treatment temperature, it was identified that the crystallized dublex coatings generally had better corrosion resistance than the amorphous coating.