A method for improving high temperature oxidation resistance of titanium-based alloys

Abstract

A method for improving the high-temperature oxidization resistance of titanium-based alloy includes the following steps that firstly, surface oxide of a titanium-based alloy matrix is removed, and then cleaning and drying are performed; secondly, characteristic ions are injected into the titanium-based alloy matrix through an ion injection method, wherein the characteristic ions are one or more of Cr, Y, Nb, F and Cl ions; thirdly, anhydrous ethanol, water and precursor alkyl silicate ester are mixed in proportion, then pH of a mixed system is adjusted to be 2.0-6.0, and stirring is performed at room temperature so that a precursor solution can be obtained; fourthly, the prepared precursor solution is added in two electrode tanks, electro-deposition is performed with the titanium-based alloy where the characteristic ions are injected as a cathode and platinum sheets or graphite as counter electrodes, a work electrode is washed in water after deposition is completed and then is dried, and a micro-nano oxide coating is obtained; and fifthly, the titanium-based alloy covered with the micro-nano oxide coating is subjected to heat treatment in air, and a coating resistant to high-temperature oxidization is obtained. The technology is simple and easy to achieve, and the high-temperature oxidization resistance of the titanium-based alloy is remarkably improved.

Description

technical field [0001] The invention belongs to the field of high-temperature oxidation resistance of metal materials, and in particular relates to a method for improving the high-temperature oxidation resistance of titanium-based alloys. technical background [0002] Titanium-aluminum alloy has the advantages of low density, high specific strength, high elastic modulus, and good high-temperature creep resistance. It is a high-temperature material with great application prospects. part. However, the actual use temperature of titanium-aluminum alloy is limited to below 750°C, because at higher temperatures, titanium and aluminum have similar affinity with oxygen, and TiO is formed on the surface of the alloy. 2 and Al 2 o 3 In the mixed layer, the growth rate of the oxide film is very fast, and it is easy to peel off. [0003] In order to overcome the above shortcomings, scholars at home and abroad have used alloying, ion implantation, surface coating, and anodic oxidatio...

AI Technical Summary

Problems solved by technology

The second is to add a third or more alloying elements, such as: Nb, Sb, Si, Cr, Y, Mo, etc. Although the high-temperature oxidation resistance of TiAl alloys can be effectively improved, too high additions usually lead to TiAl alloys Decreased mechanical properties

Although the ion implantation method has controllable implantation amount and good repeatability, the equipment involved is more expensive and the production efficiency is lower, and the depth of changing the composition of TiAl alloy is limited to the shallow range of the surface (<1μm)

And protective coatings, such as metal coating MCrAl (Y), ceramic coatings (such as SiO 2 、Al 2 o 3 and ZrO 2 etc.), and diffusion coatings (such as Al, Si, etc.), although they can be used as shielding layers to prevent oxygen from penetrating into the substrate, there are still certain problems

The interdiffusion between the metal coating and the substrate is serious, the interface is easy to precipitate hard and brittle phases, and Kirkendall holes are generated at the same time, which seriously reduces the bonding strength between the coating and the substrate; the internal stress of the ceramic coating is large and the bonding strength with the substrate is relatively weak. Low; the thermal expansion coefficient difference between the diffusion coating and the substrate is large

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