We investigated the corrosion susceptibility of Boron phosphide (BP) films deposited on stainless steel substrates by the plasma enhanced chemical vapour deposition (PECVD) process, when exposed to concentrated brine solution. The BP films were characterized with the scanning electron microscope (SEM), atomic force microscope (AFM), x-ray photoelectron spectroscopy (XPS) and Fourier transform Infra-red measurements (FTIR). The corrosion investigation involved open circuit potential (OCP) measurements for 20 hours, Potentiodynamic polarization and electrochemical impedance Spectroscopy (EIS) measurements. We also evaluated the role of the polar/dispersive components of the surface energy of the films on the corrosion process. The relationship between the polar component of the surface energy, the electric surface potential., obtained through the Poisson-Boltzmann equation using the Debye-Huckel approximation and the double layer capacitance, all related through the Zeta potential is used to explain the improved corrosion resistance of the BP films. This creates an opportunity to prepare tailor-made corrosion resistant films during plasma processing. The results of our investigation indicates that the BP coatings could provide substantial additional corrosion protection for stainless steels, when used in extreme application areas like hazardous radioactive waste containers and geothermal brine containing environments against chloride attack.
|Journal||International Journal of Electrochemical Science|
|Publication status||Published - Dec 2014|
- Boron Phosphide
- Thin films
- Surface energy
- Radioactive waste