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US 4,478,648 AGranted
Method of producing protective oxide layers
AssigneeM.A.N. Maschinenfabrik Augsburg-Nurnberg Aktiengesellschaft
InventorsHans Zeilinger, August Muhlratzer, Bruno Stemmler
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Abstract
A method for producing oxide surface layers on titanium-based objects. The object is pretreated mechanically and, following pretreatment, an oxidation process takes place using a low oxidation potential and a temperature between 480.degree. C. and 800.degree. C. As an oxidizing agent, use is preferably made of water vapor at a partial pressure of about 20 mbar. The water vapor may be mixed with an inert carrier gas, such as argon or helium.
Claims9
A method of producing a protective oxide layer on an object made of a titanium alloy, comprising the steps of:
- pretreating the surface of the object,
- thereafter oxidizing the surface of the object by heating it at a temperature in the range between about 500.degree. and 900.degree. C. in the presence of a gaseous mixture including an oxidizing agent, selected from the group consisting of water vapor and carbon dioxide, mixed with an inert carrier gas, the oxidizing being carried out without reducing the pressure of the gaseous mixture below atmospheric, and
- adjusting the oxidation potential of the oxidizing agent so as to selectively oxidize only the titanium constituent of the alloy to form the low valence oxide Ti.sub.2 O.sub.3.
Dependencies are inferred from the claim text.