DE1421047C - Process for the production of anodes from a titanium alloy with an electrically conductive nitride coating - Google Patents

Claims (3)

1 2 The invention relates to a method for producing even an extremely thin nitride layer protects depended on anodes for electrolysis, especially in the underlying metal in sufficient quantities, aggressive media, in which a carefully degreased It can, however, also form a thicker layer Titanium alloy blank to become oxygen-free. The electrical resistance of titanium nitride Namely, the atmosphere with an electrically conductive nitride-5 is extremely small (the same size coating is provided. Order like that of Titan himself). For production According to an electrode blank that is not in the state of the art, a powdery one can also be used According to the suggestion, an electrode made of a titanium alloy is pressed or molded into the electrode shape with a top layer made of a precious metal or sintered. Another resistant material compared to the invention is a method for beautiful core made of a base metal. The latter manufacture of anodes with an electrically conductive metal is provided with a barrier skin at the points where the cover layer, the nitride coating for use for electrolysis, is porous. This barrier, especially in aggressive media, can be formed from a careful skin during electrolysis, in which this wrinkled, degreased titanium alloy is used as an anode in an oxygen-free electrode made of a titanium alloy, which can be carried up to about 6 ⁰ Ai Vana. contains medium, in a nitrogen and / or ammo It has been found that such a barrier is niakatmosphäre to about 500 ⁰ C heated, skin not always proved successful. This is, inter alia, it has been shown that when used, the fact that the fine titanium alloys, which hold up to about 6% vanadium in the top layer by electrolytic means, the nitride cannot be supplied with enough energy at a much lower level To temperature (about 500 ° C) than when using pure a barrier skin suitable in every respect can be formed of titanium metal. According to a further proposal, which belongs to the powdered metal from technology, the disadvantages are to be removed, which are usually far cheaper than that of the barrier skin formed by electrolytic metal in plate form and often more easily accessible by eliminating the barrier skin Is gone. By high pressure, possibly chemical and / or thermal binding with a binder, the powder can be produced in the way. The chemically non-resistant material is at the points where it is not chemically resistant to the electrode / or thermal and / or nitrogen atmosphere to gradually increase the temperature all treatment in a stable, chemically practically inert, so that the required temperature compound or form of this material is converted. ratur z. B. is reached in the course of two hours. According to the proposal mentioned, for. B. A 35 The later cooling in this atmosphere rhodium-plated titanium plate by treatment with Am- can best be done slowly, e. B. in the course of three nionia and / or nitrogen at about 700 ° C with hours or a longer time. As a result, a barrier skin made of titanium nitride can be provided. Better adhesion of the nitride is obtained and the structure can also be improved by heating one with one. Noble metal planed titanium plate in an oxygen- 40 The electrodes in plate form can be extremely rich atmosphere a barrier skin made of titanium dioxide thin. A plate of 0.1 mm, for example, is mechanical. nically strong enough to serve as an anode per se after nitride formation on the surface. It is possible to use charge tubes, it is known to use a nitride coating, even thinner platelets, and if necessary to produce these by deposition from a TiCl ₄ containing 45, possibly by welding or in some other way in the gas phase. In this process, a conductive material must be connected to a conductive material and, in particular, temperatures between 900 and HOO ⁰ C must be connected to a base metal. So one can be applied. z. B. a thin titanium tube with molten lead. It has now been found: fill in that after solidification with the titanium in If you have a titanium alloy that is up to 6 ⁰ Ai 50 conductive connection. Contains vanadium, with a layer of titanium nitride. sees, this nitride is not only extremely resistant to all kinds of chemicals, for example, but also a good conductor of electrical current that can be converted even more easily into the nitride. Material is obtained if one starts from a titanium alloy - It was found further: 55 tion, with, for example, 4%> vanadium. It is sufficient to ensure that the nitride image is degreased and the base material does not have to be freed from an oxide layer. If you hold this plate and that just as little oxygen can enter, and 1 hour at a temperature of 500 ° C in this way the formation of a non-conductive nitrogen atmosphere, then there is an oxide layer on the outside between the titanium alloy and the 60 to a proper depth avoids chemically resisting nitride, the result is that the conductive, stable layer nitride is formed, which the nitride layer, which conducts over the entire surface of the base electricity and is a very good metal anode, proves this metal to a sufficient extent.
Dimensions protects, so that a resistant electrode is obtained without the need for the base titanium to be protected by an electrically conductive nitride coating. application for electrolysis, especially in aggressive sive media, made from a carefully degreased titanium alloy in an oxygen-free atmosphere, characterized in that a blank made of a titanium alloy, which is up to about 6% Contains vanadium, heated to about 500 ° C in a nitrogen and / or ammonia atmosphere will. 2. The method according to claim 1, characterized by the use of an anode blank, too the manufacture of which a powdered titanium alloy is pressed or molded to form the electrode was sintered. 3. The method according to claim I to 2, characterized in that when heated in the Nitrogen and / or ammonia atmosphere the final temperature by gradually increasing the temperature, z. B. in the course of two hours, is achieved and the cooling by slowly lowering the temperature in the course of several hours he follows.