Influence of processing parameters on the corrosion resistance of additively manufactured nitinol parts for biomedical applications

Abstract

The usefulness of additively manufactured (AM) nitinol and Ti6Al4V parts for the aerospace, automotive, machine and tooling, and biomedical industries depends on how well they withstand corrosion. AM is a manufacturing process that makes it possible to create intricate geometries at a reasonable price. Although significant progress has been made in decreasing metal corrosion, not much research has been done on optimizing input processing parameters to lower corrosion rates. Unique phase structures and preferential evaporation of alloying components might arise because of the melting and quick re-solidification that take place during additive manufacturing. This study looks at how processing parameter changes impact the metal parts made by laser-powder bed fusion (L-PBF) in terms of their ability to resist corrosion in a bodily environment. Electrochemical testing was used to conduct the research at a body temperature of 37 °C in both Hanks and Ringers solutions. The findings suggest that an increase in laser power during AM improves the passivation layer of the metal. Furthermore, compared to nitinol, Ti6AL4V exhibits a greater corrosion resistance. When a smaller hatch distance and lower laser beam strength were used, the nitinol sample's susceptibility to corrosion was reduced. This study demonstrates how the corrosion resistance of metal parts made by additive manufacturing can be increased by adjusting the laser powder bed fusion processing parameters in a bodily environment.

Keywords

• Corrosion resistance
• Passivation layer
• EIS
• Cyclic polarisation
• Processing parameters