Effect of Vanadium and Sodium Compounds on Accelerated Oxidation of Nickel-Base Alloys.
Abstract:
The oxidation of nickel-base alloys in the presence of gaseous and ccondensed alkali sulfates, alkali vanadates and vanadium pentoxide was studied. It was found that in the presence of condensed alkali sulfates, oxide ions present in the melt react with and render the normally protective oxide scale ineffectual. The corrosion associated with alkali sulfates can be controlled by the presence of compatible oxides which preferentially react with the oxide ions to form innocuous compounds. Vanadium pentoxide, like the alkali sulfates, accelerates the oxidation rate of nickel-base supperalloys. The product of the reaction between V2O5 and the substrates is dependent upon the alloying elements present in the alloy. In the absence of alloying elements such as aluminum and titanium, the products are vanadates. However, when the alloys contain aluminum andor titanium, the product of the reaction appears to be a glass. The study is related to corrosion inhibitions in vanadium containing fuels in gas turbines. Modified author abstract