SU956219A1 - Corrosion protection method - Google Patents

Description

(St) METHOD OF PROTECTION AGAINST CORROSION

one

The invention relates to electrophysical processing methods and can be applied in various fields of engineering to protect metals from corrosion.

The known method of corrosion protection of products from zirconium alloys by electrolytic deposition on the surface of protective layers of aluminum, chromium and subsequent diffusion treatment in vacuum or inert gas at temperatures from 600 to 1000 ° C l.

However, to carry out this method, it is necessary to thoroughly clean the surface of zirconium alloys from the oxide film according to a complex technology before coating and high temperatures of diffusion treatment in vacuum or inert atmosphere, which complicate the technology and adverse effects.

effect on the mechanical properties of zirconium alloys.

The closest to the invention is a method of protecting against corrosion of metals and alloys, including the application of a protective coating by an electric spark method using a multi-electrode-rotating tool, the electrodes of which are made

JQ of corrosion resistant material 23.

: However, this method does not sufficiently reliably protect zirconium products from corrosion.

The aim of the invention is to protect against corrosion of zirconium and its alloys.

Claims (2)

The goal is achieved by the fact that, after an electric-spark coating application with a multi-electrode rotating tool, the electrodes of which are made of corrosion-resistant material, vacuum annealing is performed at a temperature of 50.0-600 ° C for hours. The multi-electrode tool, increasing the density of electrical discharges, improves the quality, uniformity and density of the applied cover In addition, the quality of the coating can be improved. By carrying out the process of electrospray coating of coatings in an inert gas medium (helium, argon, neon), which reduces the oxidation of the surface of zirconium at the time of exposure to an electric discharge. Annealing of products in vacuum at temperatures of BOO-BOO With a duration of 3-10 hours contributes to an increase in the corrosion-protective properties of coatings, which leads to the release of surface stresses arising during the elecrographic processing and contributes to the diffusion penetration of KOino. , which improves the adhesion of the coating to the substrate. The application of the electric-spark coating method makes it possible to apply a wide range of metallic materials to the surface of zirconium alloys, which allows you to choose a metal or alloy that is more corrosion-resistant under the operating conditions of the protected part. The simplicity of the coating allows local protection (e.g., welds) of parts of complex configuration. Lower annealing temperatures compared to those used in the known method have a less negative effect on the mechanical properties of materials. Example. The coating process of chromium-containing alloys with high corrosion resistance in the environment of the SOUTH vapor on zirconium alloys Zr-1..Mb; Zr 2, 5 Nb and welded joints from Zr-2.5 Wb alloys were made using a rotating multi-electrode tool assembled from nichrome (X20H80) or steel (12X1 & H10T) 00.5 mm wires. The working electrodes in the instrument are made in separate wires, evenly spaced around the tool perimeter. The radial length of each individual wire electrode in the tool is 50 mm. An inert atmosphere for carrying out the electric-spark doping process was created by injecting an inert gas into the electric-spark discharge zone or by carrying out the process in a sealed chamber filled with an inert gas. The tool rotation speed is 900 rpm. Working voltage B. Coating thickness was controlled by the number of tool passes. After coating, vacuum annealing was carried out at a temperature of 500-600 ° C for 10 minutes h (vacuum 2.10 mm Hg). The scheme of conducting the process with the supply of inert gas to the zone of an electric spark discharge is similar. Corrosion tests were carried out in air with transmission of distilled water vapor at temperatures of 390t and in a muffle furnace in dry air at a temperature of 450 C. The temperature was maintained automatically in the range of ± 10 ° C. Corrosion rate was taken as an indicator of the qualitative assessment of the corrosion resistance of parts. In the process of corrosion testing, the appearance of the surface of the parts was evaluated, as well as the color and adhesion strength of the oxide film with the matrix. The test results showed that the name of the vacuum annealing of the above mentioned filters allows the corrosion rate to be reduced for a time. The use of annealing temperatures below is impractical due to the physicochemical properties of mi zirconium and the operating temperatures of the alloys. The use of temperatures from / 1ga above 600 C leads to a change in physicochemical, material properties. Thus, electric spark doping followed by vacuum annealing allows an increase in the resistance of zirconium alloys of dorsodermalism, prolonging the term. and alloys, including a protective coating by an electrospark method using a multi-electrode, an electric rotating tool of which corrosion is made of a non-resistant material, so that Protection against corrosion of zirconium alloys, after an electrospark nous pooy annealing of the roof produces a vacuum 5956219 " at a temperature of 500-600 C for 2. Reshetnikov S. I., Odovin S.F / 3-10 h. Application of the Electro-Spark Method Sources of information, onnogo durability of unalloyed stapled into account when examining 5 li. - Electronic processing material1. Patent of France No. 14930 0, rials, 1977, No. 3, p. ZZZb (prokl. With 23 C, published. 1967.toype). metallization to increase corrosion