Corrosion Inhibition of Sodium Chromate for Uranium-Titanium Alloy in Sodium Chloride Solution

Abstract:

The inhibition effect of sodium chromate (Na2CrO4) on uranium-titanium (U-Ti) alloy in 200 mg/L NaCl solution was evaluated with the weight-loss method and the electrochemical method. The feature of the oxide film formed on the U-Ti alloy sample surface was analyzed with X-ray photoelectron spectroscopy (XPS) and laser confocal microscope. The results show that Na2CrO4 is anodic inhibitor for U-Ti alloy and the inhibition efficiency increases with its concentration increasing. The efficiency is influenced greatly by the temperature of corrosion solution. The corrosion rate of U-Ti alloy sample is greater in 100 mg/L Na2CrO4 solution than in uninhibited solution when the solution temperature is higher than 45 oC. The XPS analysis indicates that there are two types of uranium oxide in the passive film of U-Ti alloy surface. UO2+x is in the outer layer in the film while UO2 in the inner layer. The outer layer of passive film includes UO2+x and some chromium compounds when Na2CrO4 is added into NaCl solution, and the thickness of the outer layer is less than 3 nm.

Key words:weight-loss; electrochemical; sodium chromate; U-Ti alloy; XPS