Synthesis and Characterization of Silica-Titanium Oxide Nano-Coating on NiTi Alloy

To functionalize the surface of the NiTi alloy, hybrid layers comprising nanometric silica and titanium oxides were synthesized. The TiO2–SiO2 nanosystem was chemically prepared and utilized for electrophoretic deposition (EPD) to create multifunctional layers on the alloy surface. The impact of pH on Zeta potential and ceramic particle size was explored to ensure a stable colloidal suspension for EPD, with optimal parameters established at a pH of approximately 6. A uniform layer was formed by applying a voltage of 40 V for 3 min, appearing as a thin film interspersed with regularly spaced larger agglomerates. The thin film primarily consisted of a minor fraction of defective rutile nanoparticles, accompanied by silica and carbon agglomerates from the nanosystem synthesis process. Heat treatment at 800 °C for 2 h induced significant structural changes, developing a novel-generation material with a different structure. An interlayer with strong Si–O–Ti connections was formed. Moreover, the mechanism of layer formation was extensively discussed.