A method for preparing iron-based magnetostrictive coatings using thermal spraying technology

Abstract

The invention discloses a method for preparing an iron-based magnetostrictive coating by using a thermal spraying technology, which belongs to the field of magnetic materials. The iron-based magnetostrictive material is firstly prepared into spherical gas-atomized powder, and then the metal material is used as the substrate, and the spherical gas-atomized powder is sprayed onto the metal substrate by plasma spraying to prepare the iron-based magnetostrictive coating. The specific steps are to first melt the iron-based magnetostrictive material into an ingot in a vacuum melting furnace, remove the scale on the surface by machining, and then send the ingot to a high-pressure atomization powder making device, and melt the ingot through a high-speed argon gas flow. The alloy stream breaks up into small droplets and condenses into powder. Thermal spraying technology adopts plasma spraying. The plasma gas is mainly nitrogen, supplemented by hydrogen. The iron-based magnetostrictive gas atomized powder is sent into the plasma chamber, and the coating is formed by heating, melting, flying, impacting the substrate, cooling and solidification. Its advantages are: high bonding strength of the coating, fine structure, low porosity, and the addition of alloying elements reduces oxide slag inclusions.

Description

technical field [0001] The invention belongs to the field of magnetic materials, in particular to a method for preparing an iron-based magnetostrictive coating using thermal spraying technology Background technique [0002] Ferromagnetic substances have a crystal-like structure, with iron negative ions surrounded by electron clouds in the center of iron positive ions. In ferromagnetic substances, between adjacent atoms, due to the spin of electrons, the elemental magnetic moment is generated, and there is an interaction force between the elemental magnetic moments, which drives the adjacent elemental magnetic moments to be arranged in the same direction to form a magnetic domain , the interaction between magnetic domains is very small. When there is no external magnetic field, the magnetic domains are balanced with each other, and the total magnetization of the material is equal to zero. When there is an external magnetic field, this balance is destroyed, and the magnetiza...

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Problems solved by technology

The thin belt is fixed by epoxy resin between the tested samples, and it is also used as the coupling medium between the magnetostrictive thin belt and the tested sample for ultrasonic guided waves, but the epoxy resin cannot resist the heavy underground Moisture, the coating is easy to protrude, and bulges will be formed in the early stage, which will crack and fall off after long-term use, and the anti-ultraviolet ability is poor, so it cannot be used outdoors for a long time, otherwise it will accelerate aging, such as discoloration, strength reduction or even powdering, falling off, etc. Therefore, alloy thin strips cannot be used for ultrasonic guided wave detection and in-service monitoring for a long time, so magnetostrictive coating is considered, and the powder of magnetostrictive material is sprayed on the surface of the tested sample to form a coating coating, which has high bonding strength. , dense, can be used for long-term ultrasonic guided wave detection, to achieve permanent service

[0005] Magnetostrictive coatings are made of magnetostrictive materials, and their preparation methods mainly include coating deposition methods, including vacuum evaporation, sputtering, ion plating, and chemical vapor deposition (CVD). Sputtering, ion plating and other methods to prepare conductive coatings have the following problems: the equipment is expensive and the cost is too high; an ultra-high vacuum system is required, and the requirements for plating materials are too high. These methods have strict requirements on the size of the substrate and are not suitable for Large-scale spraying cannot be used in large-scale industries; thermal spraying technology has no restrictions on the size and shape of the substrate, the surface is less affected by heat, is not easy to deform, and the thickness of the coating is easy to control, which can make the surface of the material obtain different hardness, wear resistance, Special properties such as corrosion resistance and oxidation resistance, simple process operation procedures and high efficiency

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