کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1604317 | 1516001 | 2010 | 8 صفحه PDF | دانلود رایگان |
The electrochemical behaviour of AlCrSiN coatings deposited on WC–Co substrates has been studied using potentiodynamic and potentiostatic polarization techniques in solutions consisting of 0.5 M H2SO4 and different concentrations of oxalic and citric acids. Polarization curves show that coatings are efficiently removed by applying current densities around 70 mA/cm2 for 5 to 10 min. Both oxalic and citric acids act as corrosion inhibitors protecting the hardmetal substrate after the coating removal. In both cases the maximum inhibition efficiency is obtained for concentrations around 0.1 M. Corrosion protection can be associated to the adsorption of carboxylic groups onto the hardmetal substrate. The free energies calculated by applying the Langmuir equation to the corrosion currents are in the range of those found for physisorption phenomena. Electrolytes based on citric additions lead to higher adsorption constants (Kads), which could explain their higher inhibition efficiency.
Journal: International Journal of Refractory Metals and Hard Materials - Volume 28, Issue 2, March 2010, Pages 155–162