Biocompatibility is a critical requirement in the selection of materials for biomedical implants. Among the most extensively studied materials, Nitinol (NiTi)—an equiatomic nickel–titanium alloy—has surpassed conventional implant materials such as stainless-steel owing to its unique properties, including the shape memory effect, super elasticity, and excellent corrosion resistance [1,2]. In biomedical applications, NiTi is widely used in devices such as vascular stents, orthopedic implants, and guidewires [3].

The transition from conventional fabrication routes, such as casting and sintering, to additive manufacturing (AM) offers significant advantages, including the production of complex geometries and reduced material waste. However, additive manufacturing of NiTi remains challenging due to rapid solidification rates and the potential formation of brittle secondary intermetallic phases (e.g., TiNi₃ and Ti₂Ni), which can adversely affect mechanical performance and corrosion resistance.

This study investigates the effect of thermal treatment—specifically base-plate preheating—on the corrosion behavior of in-situ alloyed and pre-mixed NiTi fabricated by Laser Direct Metal Deposition (LDMD), with comparisons made to conventionally cast NiTi. Corrosion performance was evaluated using potentiodynamic polarization testing in Hank’s solution to simulate physiological conditions, in accordance with ASTM G59. The results indicate that non-preheated, in-situ alloyed NiTi exhibits superior corrosion resistance compared to preheated samples, pre-mixed NiTi, and as-cast counterparts