Improved corrosion resistance of selective laser melted NiTi alloys via nanosecond pulsed laser annealing treatment for biomedical application

Abstract

NiTi alloys, known for their excellent biocompatibility, have broad application prospects in the biomedical field, making surface quality and corrosion resistance critical for practical applications. This study employs nanosecond pulsed laser annealing to improve the surface properties of NiTi alloys fabricated by selective laser melting (SLM). The results show that laser annealing significantly reduces surface roughness, with the average roughness (Ra) decreasing from 8.76 µm to 1.42 µm. Meanwhile, potential dynamic polarization analysis conducted at 37 °C in Hank’s solution indicates that laser annealing effectively enhances corrosion resistance, with the corrosion potential shifting positively from -0.68 V to -0.23 V and the corrosion current density decreasing from 3.580 μA·cm⁻² to 0.151 μA·cm⁻². This improvement is attributed to the reduction in surface roughness, grain refinement, and the formation of a more stable oxide layer through laser annealing. This study not only validates the potential of laser annealing for surface modification of SLMed NiTi alloys but also provides valuable insights for their further optimization in biomedical applications.