Print Email Facebook Twitter Passive film formation and corrosion resistance of laser-powder bed fusion fabricated NiTi shape memory alloys Title Passive film formation and corrosion resistance of laser-powder bed fusion fabricated NiTi shape memory alloys Author Liu, M. (TU Delft Team Arjan Mol) Zhu, Jia-Ning (TU Delft Team Vera Popovich) Popovich, V. (TU Delft Team Vera Popovich) Borisov, E. (Peter the Great Saint-Petersburg Polytechnic University) Mol, J.M.C. (TU Delft Team Arjan Mol) Gonzalez Garcia, Y. (TU Delft Team Yaiza Gonzalez Garcia) Date 2023 Abstract Electrochemical tests and surface analysis measurements were performed to study the corrosion behavior in a 0.9 wt.% NaCl solution at 37 °C of three NiTi shape memory alloys fabricated by laser-powder bed fusion (L-PBF). The passive film characteristics and corrosion resistance of L-PBF NiTi showed different features as a function of their preparation process settings. The passivation rate for L-PBF NiTi surfaces including defects, such as keyhole pores and cracks which showed high electrochemical activity accelerating the passivation reaction process, was higher in the early stages of immersion, but the corrosion resistance provided by such a rapidly formed passive film containing higher defect density is lower than that for an initially defect-free surface. The thickness of the passive film including a higher defect density does not necessarily relate to the corrosion resistance. The L-PBF NiTi prepared at a linear energy density of 0.2 J/m and volumetric energy density of 56 J/mm3 shows the least defects. Also, an outer Ti-rich and inner Ni-rich dense and corrosion protective passive film could be obtained for these L-PBF NiTi samples, which also results in a relatively low Ni ion release rate. A passive film model based on thickness, composition and defect density properties as a function of processing conditions is proposed to explain the difference in corrosion resistance of the various L-PBF NiTi. Subject Auger electron spectroscopyCorrosionLaser-powder bed fusionNiTiPassivationShape memory alloysX-ray photoelectron spectroscopy To reference this document use: http://resolver.tudelft.nl/uuid:a418a84a-5e5b-4849-b288-23ab9f30cbe8 DOI https://doi.org/10.1016/j.jmrt.2023.01.204 ISSN 2238-7854 Source Journal of Materials Research and Technology, 23, 2991-3006 Part of collection Institutional Repository Document type journal article Rights © 2023 M. Liu, Jia-Ning Zhu, V. Popovich, E. Borisov, J.M.C. Mol, Y. Gonzalez Garcia Files PDF 1_s2.0_S2238785423002065_main.pdf 4.83 MB Close viewer /islandora/object/uuid:a418a84a-5e5b-4849-b288-23ab9f30cbe8/datastream/OBJ/view