Abstract
The corrosion of zirconium of four different analyses including iodide, Hf-free reactor grade, an Hf-containing high purity grade, and an Hf-containing low purity grade zirconium, has been studied at 150–250 C in an aqueous solution containing 20 percent HCl. Studies of the reaction kinetics and surface phenomena have been made in extensive experiments. The results of the experimental work are discussed with detailed consideration being given to the role of impurities, the heterogeneous nature of corrosion, the influence of the electrolyte, surface preparation and diffusion barriers.
It was concluded in general that small concentrations of specific impurity elements which formed precipitate phases had a powerful influence on the dissolution rate of zirconium and the resistance of primordial oxidic protective films. Iron, nickel, chromium, manganese, and silicon as impurities are believed to be most detrimental to the corrosion resistance of annealed zirconium in the form of precipitate particles acting as anodic corrosion centers. Various ways of improving the corrosion resistance of zirconium in HCl are either suggested or implied in the experimental results and their discussion. 6.3.20, 4.3.2, 3.7.2
Garnet Electrolyte Surface Degradation and Recovery
