Erosion-corrosion behavior and electrochemical performance of Hastelloy C22 coatings under impingement
Abstract
The erosion-corrosion behavior of Hastelloy C22 coating prepared by multilayer laser cladding technology is investigated under impingement by solid-liquid flow. Three external factors are taken into consideration including fluid flow velocity, impact angle and erosion time. The total weight loss and corrosion current density increase with the increase in flow velocity. But the passive current density reduces when velocity is over 4 m/s. The combination effect of shear and normal stress leads to the maximum of total weight loss at 60°, but electrochemical measurements show lowest corrosion resistance at 30° due to dominant shear stress and highest value at 60° because of stronger protection of passive film. As expected, both weight loss and corrosion rate increase with erosion time extending. The microhardness of coating surface increases after impingement. The impact of solid particles on surface produces typical craters with different shapes and sizes. The low annual corrosion rate of Hastelloy C22 coating shows the efficacity of multilayer laser cladding technology.
- Publication:
-
Applied Surface Science
- Pub Date:
- October 2018
- DOI:
- 10.1016/j.apsusc.2018.06.209
- Bibcode:
- 2018ApSS..456..985C
- Keywords:
-
- Erosion-corrosion;
- Hastelloy C22 coating;
- Electrochemistry;
- Weight loss