<p>This work explores the environment-induced degradation response of ternary NiTiSi shape memory alloys (SMAs) prepared by vacuum induction melting with silicon content variations of 3, 6, and 9 at.%. High-purity silicon, titanium, and nickel were melted, cast, hot-rolled, homogenized, and water-quenched with subsequent analyses of microstructure and compositional analyses using SEM, TEM, EDS, and CHNOS techniques. Electrochemical properties were assessed from potentiodynamic polarization experiments in Hank’s solution, with physiological conditions, with corrosion rate and current density derived from Tafel plots. Transformation temperatures were obtained from differential scanning calorimetry (DSC), while SEM studies after corrosion experiments gave details of degradation mechanisms on the surface. Results showed that increased silicon content increased transformation temperatures, with maximum temperature stability for the 9 at.% Si alloy, NTS3. CHNOS supported reduced impurity content of NTS3 with fewer TiC and Ti(C,O) inclusions and a stable TiO₂ passive layer. Results from potentiodynamic studies showed a progressive decrease in corrosion rate with increased Si, where NTS3 exhibited minimum current density and enhanced corrosion resistance over that of CpTi and equiatomic NiTi alloy. SEM images verified a transition from local pitting of low-Si to smoother reduced corrosion for NTS3. These results identify NiTiSi alloys, and especially NTS3, to be novel candidates for biomedical implants that demand prolonged electrochemical stability.</p>