Box-Behnken design for the optimization of the surface protection against corrosion of turbochargers using zirconium doped-titanate nanotubes

The aim of this work was the protection of the turbine blades from corrosion in an acid medium using different nanotubes as surface corrosion protectors. The plan of this article was to study the anticorrosion properties of zirconium doped titanate nanotubes materials. Inhibitors were prepared using hydrothermal method at different zirconium contents (2; 5 and 10 wt%). The obtained powders were characterized using different techniques: X-ray diffraction (XRD), electronic transmission microscopy (TEM), N2 adsorption–desorption, ICP analysis and Raman spectroscopy. The results revealed a hollow tubular structure of nanotubes having lengths around 120 nm. The anticorrosion efficiency results showed a significant inhibitory rates of the titanate nanotubes which increases with the increase in the Zr content. The working conditions were evaluated using the modeling based on ANOVA studies. The results proved that the inhibition rate is considerably influenced by a positive individual effect of the acid contact time, the temperature of the environment and the mass of the inhibitor. The most favorable conditions were achieved under 100 mg of inhibitor, during 3 h at 15 °C which leaded to reach 100% of inhibition rate. Finally, the adsorption kinetics of the nanotubes on the Ni-alloy surface followed the Langmuir model.