Cold-Sprayed Cu-Zn-Al2O3 Coating on Magnesium Alloy: Enhanced Microhardness and Corrosion Behavior

• Published in: Journal of materials engineering and performance 2023-07, Vol.32 (14), p.6160-6174
• Main Authors: Mouli, G. Chandra, Chakradhar, R. P. S., Srivastava, Meenu, Barshilia, Harish C.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Materials Science; Quality Control; Reliability; Safety and Risk; Technical Article; Tribology
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-022-07551-4

The present paper is aimed to improve the microhardness and corrosion protection of magnesium (AZ31B) alloy by employing Cu-Zn-Al 2 O 3 coating through cold spray method. A fully dense coating of thickness ~ 877 μm has been achieved due to hammering effect of dense Al 2 O 3 particles. The compositional and microstructural analysis of feedstock powder as well as coatings has been studied and discussed. An enhanced microhardness value of 219 ± 7 HV 0.1 (~ 3 times higher) is obtained for Cu-Zn-Al 2 O 3 coating compared to bare Mg alloy substrate (70 ± 10 HV 0.1 ). The corrosion properties of the coatings were examined by potentiodynamic polarization and long-term immersion tests (24, 48, 96 and 336 h) in a 3.5% NaCl solution. Long-term immersed samples showed a positive shift in potential compared to the as-sprayed coated sample. The polarization resistance ( R p ) measured is well in accordance with the measured I corr . Coated samples after immersion for 336 h in 3.5% chloride medium resulted in the formation of a protective passive layer of ZnO and simonkolleite on the surface, which is responsible for corrosion protection of AZ31B alloy. These results are well supported by FESEM, EDAX and XRD data. This study provides an eco-friendly approach for corrosion protection of AZ31B alloy.