Oxidation properties of tungsten wire treated through electrochemical corrosion in air

Behavior and process of oxidization of ultra-fine tungsten wire prepared by electrochemical corrosion technology were studied using SEM photography, energy spectrum, XRD and mechanical property test. It was shown that black-brown oxidized products in the air were complex oxidates where oxygen quantivalence was between +4 and +6. Mass percent of oxygen in the surface of ultra-fine tungsten wire after electrochemical corrosion had already exceeded 1%. While the tungsten wire was oxidating in air, oxygen content in the surface of tungsten wire first increased and then decreased. Regular strips formed on the surface of W wire after electrochemical corrosion, while 10 months after oxidation, irregular striation appeared, and 85 months after fluctuation of both regular strips and irregular striation tended to be weak. Break-down strength of tungsten wire decreased but ductility changed little after oxidation. Such properties may relate with both protective and un-protective properties of oxidate of W.