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Corrosion-resistant coating on surface of sintered neodymium-iron-boron magnet and preparation method of surface corrosion-resistant coating

A technology of NdFeB and corrosion resistance, which is applied in the field of corrosion resistance coating on the surface of sintered NdFeB magnets and its preparation, can solve the problems of corrosion resistance, brittleness resistance and insulation effects, and achieve excellent bonding performance, Uniform structure distribution and improved surface corrosion resistance

Pending Publication Date: 2020-11-13
NANCHANG HANGKONG UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the micro-arc oxidation technology has the advantages of simple workflow, easy operation, excellent bonding performance between the pollution-free layer and the substrate, and the excellent properties of both metal and ceramics. The obtained in-situ growth oxide ceramics, but there are also loose and porous micro-arc oxidation ceramic layers. , this structure has an impact on the corrosion resistance, brittleness and insulation of the material surface, and it is powerless for some demanding environments

Method used

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  • Corrosion-resistant coating on surface of sintered neodymium-iron-boron magnet and preparation method of surface corrosion-resistant coating

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Put the sintered NdFeB magnet obtained by the surface micro-arc oxidation in Comparative Example 1 into a pulse plasma explosion treatment device, use the pulse plasma explosion treatment process to carry out surface treatment on the sintered NdFeB magnet and then dry it naturally to obtain a surface containing Sintered NdFeB magnets with dense micro-arc oxidation ceramic coating; the plasma explosion treatment device adopts pure tungsten electrodes, the power supply voltage is 5 KV, the working capacitance value is 800 μ F, and the number of pulses is 3 times; the pulse plasma explosion treatment device The mixture of propane, oxygen and compressed air is used as the explosive gas, and the ratio between propane, oxygen and compressed air is 1: 4: 3.5; pure tungsten material is used as the electrode for detonation, and the explosive gas is sprayed from the spray gun Surface treatment was carried out on the test piece, the distance between the outlet of the spray gun and ...

Embodiment 2

[0033] Put the sintered NdFeB magnet obtained by the surface micro-arc oxidation in Comparative Example 1 into a pulse plasma explosion treatment device, use the pulse plasma explosion treatment process to carry out surface treatment on the sintered NdFeB magnet and then dry it naturally to obtain a surface containing Sintered NdFeB magnets with dense micro-arc oxidation ceramic coating; the plasma explosion treatment device adopts pure tungsten electrodes, the power supply voltage is 5 KV, the working capacitance value is 800 μ F, and the number of pulses is 3 times; the pulse plasma explosion treatment device The mixture of propane, oxygen and compressed air is used as the explosive gas, and the ratio between propane, oxygen and compressed air is 1: 4: 3.5; pure tungsten material is used as the electrode for detonation, and the explosive gas is sprayed from the spray gun Surface treatment was carried out on the test piece, the distance between the outlet of the spray gun and ...

Embodiment 3

[0039] Put the sintered NdFeB magnet obtained by the surface micro-arc oxidation in Comparative Example 1 into a pulse plasma explosion treatment device, use the pulse plasma explosion treatment process to carry out surface treatment on the sintered NdFeB magnet and then dry it naturally to obtain a surface containing Sintered NdFeB magnets with dense micro-arc oxidation ceramic coating; the plasma explosion treatment device uses pure tungsten electrodes, the power supply voltage is 5 KV, the working capacitance value is 1000 μF, and the number of pulses is 2 times; the pulse plasma explosion treatment device The mixture of propane, oxygen and compressed air is used as the explosive gas, and the ratio between propane, oxygen and compressed air is 1: 4: 3.5; pure tungsten material is used as the electrode for detonation, and the explosive gas is sprayed from the spray gun Surface treatment was carried out on the test piece, the distance between the outlet of the spray gun and th...

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Abstract

The invention discloses a corrosion-resistant coating on the surface of a sintered neodymium-iron-boron magnet and a preparation method of the corrosion-resistant coating. The preparation method comprises the following steps that a neodymium-iron-boron magnet is cleaned with deionized water after being soaked in an alkaline solution, then the neodymium-iron-boron magnet is ultrasonically cleaned with absolute ethyl alcohol after being soaked in an acidic solution to obtain a pretreated neodymium-iron-boron magnet; then the pretreated neodymium-iron-boron magnet is put into an electrolyte prepared from NaAlO2, Na2SiO3 and deionized water, the neodymium-iron-boron magnet is treated by adopting a micro-arc oxidation process, and ultrasonic cleaning is carried out after treatment to obtain a micro-arc oxidized neodymium-iron-boron magnet; and finally, surface treatment is carried out by adopting a pulse plasma explosion process, and natural airing is carried out to obtain the sintered neodymium-iron-boron magnet with the corrosion-resistant coating on the surface. According to the corrosion-resistant coating prepared through the method, the coating and the base body are tightly wrappedtogether, a surface texture structure is distributed evenly, the coating is flatter and more compact, and the surface is free of defects such as melting pits, so that corrosive liquid is greatly prevented from diffusing to the base body, and the corrosion resistance is greatly improved.

Description

technical field [0001] The invention relates to the technical field of surface treatment of magnetic materials, in particular to a corrosion-resistant coating on the surface of a sintered NdFeB magnet and a preparation method thereof. Background technique [0002] Sintered NdFeB permanent magnets (NdFeB) have been widely used in wind power generation, new energy vehicles, energy-saving inverter air conditioners, energy-saving elevators, robots, aerospace and intelligent manufacturing due to their excellent magnetic properties. However, there are a lot of pores and looseness on the surface of sintered NdFeB material, which is easy to oxidize and rust, and its chemical stability and corrosion resistance are poor. In addition, due to its own multi-phase structure, there is a large chemical potential difference between the phases, which leads to the preferential decomposition of the intergranular neodymium-rich phase and boron-rich phase, making the ferromagnetic main phase Nd ...

Claims

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Application Information

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IPC IPC(8): C25D11/34C25D7/00H01F41/02
CPCC25D11/34C25D11/026C25D7/001H01F41/026Y02E10/72
Inventor 罗军明谢宇徐吉林
Owner NANCHANG HANGKONG UNIVERSITY
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