Electrochemical Properties of Certain New Ternary and Quaternary Alloys Based on Aluminum

摘要

The effect of adding small amounts of various elements to aluminum on its electrochemical behavior was studied. It was demonstrated that 0.1% In, Ga, and Tl significantly changes three properties of aluminum and this otherwise electrochemically inactive metal is thus converted into a metal that can be used as a highly active anode in galvanic elements or in anticorrosion protection. These three properties are: the stationary potential (which for pure aluminum in a chloride solution amounts to only -0.56 V vs a normal hydrogen electrode, while with alloying it becomes more negative by several hundred millivolts); corrosion in an open circuit (which must be limited so that considerable self-discharge, i.e., unproductive consumption of the metal, does not occur); and corrosion of the metal during anode dissolution, which manifests itself by evolution of gaseous hydrogen and can be increased or decreased by increasing the anode current density and which is referred to in the electrochemical literature as a negative or positive differential effect. It was demonstrated that the introduction of additives reduces the negative differential effect (e.g., from 14% for pure aluminum to 0.5% for the alloy Al-In) and increases anodic utilization of aluminum correspondingly (from 86% to 99.5%). Two ternary combinations (Al-In-Tl) and Al-In-Ga) and a quaternary alloy with all three alloying elements (Al-In-Ga-Tl) were studied. (ERA citation 05:016177)