Technical Note: Experimental Survey of Corrosion Potentials for Rare Earth Metals Ce, Er, Gd, La, and Nd as a Function of pH and Chloride Concentration

There is a paucity of information regarding electrochemical properties of rare earth (RE) elements in their pure metal form in aqueous solutions. Given the significant use of RE metals as functional alloying additions to magnesium alloys, an elementary knowledge of their unique potentials is warranted. Further, the difference in characteristic potentials of different RE elements is also of relevance. Herein we have surveyed the elements cerium, erbium, gadolinium, lanthanum, and neodymium in room temperature chloride solutions ranging from 0.01 M to 0.6 M sodium chloride (NaCl), at the pH values of 3, 6, and 11. All potentials surveyed were within the window of −1.8 V vs. saturated calomel electrode (SCE) to −1.4 VSCE, while the different RE elements surveyed each had unique potentials.