Corrosion performance of bi-layer Ni/Cr 2 C 3 –NiCr HVAF thermal spray coating

• DOI: 10.1016/j.apsusc.2016.02.002
• Publication Date: 2016-02-03T17:02:01Z
• Authors: E. Sadeghimeresht; N. Markocsan; P. Nylén; S. Björklund
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract The corrosion behavior of three HVAF thermal spray coating systems (A: single-layer Ni, B: single-layer Cr 2 C 3 –NiCr coatings, and C: bi-layer Ni/Cr 2 C 3 –NiCr coating) was comparatively studied using immersion, salt spray, and electrochemical tests. Polarization and EIS results showed that the corrosion behavior of Cr 2 C 3 –NiCr coatings in 3.5 wt.% NaCl solution was significantly improved by adding the intermediate layer of Ni. It was illustrated that the polarization resistance of the bi-layer Ni/Cr 2 C 3 –NiCr and single-layer Cr 2 C 3 –NiCr coatings were around 194 and 38 kΩ cm 2 , respectively. Microstructure analysis revealed that the bond coating successfully prevented the corrosion propagation toward the coating.