Nickel was electrodeposited from choline chloride (ChCl)-based deep eutectic solvents (DESs) containing ethylene glycol (EG) and urea (U) on Cu substrate. The influence of the temperature and of DESs nature was evaluated. The diffusion coefficients of nickel varied from 2.2 × 10 −9 to 3.7 × 10 −8 cm 2 s −1 for ChCl:2U and from 1.3 × 10 −8 to 5.8 × 10 −8 cm 2 s −1 for ChCl:2EG with increasing temperature. The nucleation process of Ni on Cu at 70 °C was determined as instantaneous in ChCl:2EG and progressive in ChCl:2U using Scharifker and Hills model. The SEM characterization showed that with increasing temperature, more compact coatings were obtained. Linear polarization and electrochemical impedance spectroscopy were used to evaluate the corrosion performance of the obtained deposits in 3.5% NaCl. The coatings were more protective as higher the temperature of deposition, with polarization resistance (R p) values from 3.53 to 19.11 kΩ cm 2 .

Model Fe-9Cr-xMo alloys with high Mo content alloys were cast to investigate the effect of Mo on the phase evolution and properties of the alloys. The Mo contents in the alloys were 5, 7, and 9 wt%, while the Cr content was held constant at 9 wt%. For comparison, a commercial A213T 9-P9 (Fe-9Cr-1Mo) alloy, widely used in the petrochemical industry, was also investigated. The alloys were heat-treated at temperatures between 450 and 650°C and characterized by scanning electron microscopy, x-ray dispersive energy spectroscopy, and electron backscatter diffraction. Potentiodynamic linear polarization technique was used to evaluate the corrosion of the alloys in a 0.5 mol L À1 H 2 SO 4 solution containing 0.1 mol L À1 NaCl. The results showed that the corrosion resistance of the alloys was affected by precipitation of the l phase and that the Mo content in excess of 5% is deleterious to the corrosion resistance of the Fe-Cr-Mo alloys.