Investigation of bio-corrosion behavior, structural and thermal properties of Ni20Ti50Sn30 high-temperature shape memory alloy

• Published in: Journal of thermal analysis and calorimetry Vol. 149; no. 17; pp. 9085 - 9093
• Main Author: Balci, Esra
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.09.2024; Springer Nature B.V
• Subjects: Alloying elements; Analytical Chemistry; Biocompatibility; Chemistry; Chemistry and Materials Science; Corrosion tests; Crystal structure; Electric arc melting; Electrochemical impedance spectroscopy; Enthalpy; Heat resistant alloys; High temperature; Inorganic Chemistry; Martensite; Martensitic transformations; Measurement Science and Instrumentation; Morphology; Physical Chemistry; Polymer Sciences; Precipitates; Scanning electron microscopy; Shape memory alloys; Thermodynamic properties; Titanium dioxide; Transformation temperature; X ray analysis; Thermal properties; High-temperature shape memory alloys; NiTiSn; Bio-corrosion; EIS
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-024-13376-1

In this study, Ni 20 Ti 50 Sn 30 (atomic %) sample was prepared using the arc melting method. Some thermodynamic parameters (phase transformation temperatures, PTT; enthalpy, Δ H ; and phase transformation hysteresis, H ) obtained from the phase transformations of the alloy were determined using differential scanning calorimetry (DSC). The sample exhibited high-temperature shape memory alloy (HTSMA) properties. X-ray (XRD) analysis was performed to determine the crystal structure properties at the alloy. The presence of B2, B19′, Ti 2 Ni, β-Ti, Ni 3 Sn 4 , TiNiSn and Ti 3 Sn phases was identified through X-ray analysis of the alloy. Scanning electron microscopy (SEM) was used to examine the pre- and post-corrosion surface morphologies of the sample, with EDX analysis being performed to reveal chemical structure determinations (matrix phases, precipitates and weathering zones). The presence of dendritic arms was observed, while martensite plates were absent in all SEM images. Particularly in the SEM image taken after corrosion, it was noted that the TiO 2 layer placed on the surface of the matrix rich in Ti elements altered the surface morphology of the alloy. The presence of Ti and O elements in the post-corrosion EDX analysis confirmed the existence of this layer. Biocompatibility studies of the alloy were conducted using potentiodynamic corrosion tests and electrochemical impedance spectroscopy (EIS) methods. It was determined that the NiTiSn sample was in the excellent stability class according to corrosion standards.