Corrosion resistance of tin coatings deposited by cold spraying

Abstract

This article presents a study of corrosion resistance of tin and tin-based composite (Sn + Al₂O₃ and Sn + SiC) coatings deposited onto aluminium alloy substrates using the low-pressure cold spraying method. The samples were subjected to three different corrosion tests at a room temperature: (i) Kesternich test, (ii) a cyclic salt spray test and (iii) anodic polarisation test. The selected tests allowed extreme environment simulation typical for wide range of urban, industrial and marine service conditions. Evaluation of corrosion was carried out by analysing changes on the coating surface as well as in the microstructure. Additionally, the physicochemical tests were carried out using X-ray diffraction. XRD analysis clearly showed that abhurite Sn₂₁O₆Cl₁₆(OH)₁₄ is the main corrosion product established after the polarisation measurements. Despite extreme corrosive conditions used in experiments all tin coatings showed minor corrosion changes which implies that abhurite serves as a buffer between the metal and the oxidising natural environment.

Keywords:

• Tin coatings
• Cyclic salt spray test
• Kesternich test
• Polarisation measurements
• XRD phase analysis

Acknowledgements

The authors would like to thank Marzena Lachowicz, Ph.D., for her technical support in conducting potentiodynamic measurements, which enabled the whole analysis of corrosion protection of LPCS coatings.

Funding

This paper is based on the research supporterd by the the Foundation for Polish Science (FNP).