CN111020482A - Sintered NdFeB magnet surface densification Al coating and preparation method thereof - Google Patents
Sintered NdFeB magnet surface densification Al coating and preparation method thereof Download PDFInfo
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- CN111020482A CN111020482A CN201911230623.7A CN201911230623A CN111020482A CN 111020482 A CN111020482 A CN 111020482A CN 201911230623 A CN201911230623 A CN 201911230623A CN 111020482 A CN111020482 A CN 111020482A
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/14—Metallic material, boron or silicon
- C23C14/16—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/58—After-treatment
- C23C14/5886—Mechanical treatment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
- H01F41/026—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets protecting methods against environmental influences, e.g. oxygen, by surface treatment
Abstract
The invention discloses a preparation method of a sintered NdFeB magnet surface densified Al coating, which comprises the following specific steps: the ball milling treatment is carried out on the Al coating evaporated on the surface of the sintered NdFeB magnet, the densification of the Al coating is realized, the pores generated by columnar crystal production of Al in the evaporation process are closed, and the corrosion resistance and the surface hardness of the evaporated Al coating are improved. The method solves the problems of low compactness, poor corrosion resistance and the like of the Al coating evaporated on the surface of the magnet, realizes the densification of the evaporated coating on the basis of keeping high bonding force between the evaporated coating and a substrate, and provides a longer-acting corrosion protection effect for the sintered NdFeB magnet.
Description
Technical Field
The invention belongs to the field of surface protection and corrosion-resistant coatings of magnetic materials, and particularly relates to a sintered NdFeB magnet surface densified Al coating and a preparation method thereof.
Background
The neodymium iron boron magnet is used as a functional material, and the organization structure and the components of the neodymium iron boron magnet enable the material to have high chemical activity and difficult to exist stably for a long time in the environment. The main reasons for the corrosion are that the element Nd has high chemical activity and is easy to oxidize, and the multiphase structure of the magnet has large difference in the electrode potential between phases, so that the electrochemical corrosion is easy to occur. These seriously limit the further expansion of the application field of sintered NdFeB magnets, so measures must be taken to improve the corrosion resistance of sintered NdFeB magnets, and the surface protection treatment method is mainly adopted in the current industrial production to add a protective coating on the surface of the magnet, so that the corrosion resistance of the magnet can be obviously improved.
At present, the common protection measures for the surface of the sintered NdFeB magnet are as follows: electroplating, electroless plating, organic coatings, physical vapor deposition, composite coatings, and the like. The physical vapor deposition aluminizing on the surface of the neodymium iron boron is an anti-corrosion means of the neodymium iron boron magnet, the obtained plating layer is silvery white and has good bonding force with the magnet, but columnar crystals on the surface of the plating layer are thick, a large number of holes and gaps exist, the compactness is not high, and therefore the corrosion resistance of the plating layer is poor.
Therefore, the sintered NdFeB magnet surface densified Al coating and the preparation method thereof have important economic and social benefits.
Disclosure of Invention
The invention provides a preparation method of a sintered NdFeB magnet surface densified Al coating, aiming at the problems of low compactness, poor corrosion resistance and the like of a sintered NdFeB magnet surface metal coating, and aims to improve the corrosion resistance of the sintered NdFeB magnet surface densified Al coating.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a preparation method of a sintered NdFeB magnet surface densified Al coating comprises the following specific steps:
(1) preparing an Al coating: preparing an Al coating on the surface of the sintered NdFeB magnet by adopting vacuum evaporation;
(2) high-energy ball milling: and putting the sintered NdFeB magnet with the Al coating evaporated and the grinding balls into a ball milling tank for ball milling, taking out the sintered NdFeB magnet after ball milling, cleaning and drying to finish the surface densification of the Al coating.
Further, the specific preparation method of the Al coating in the step (1) is as follows: and (3) loading the magnet subjected to acid cleaning treatment into a furnace, vacuumizing, performing bombardment cleaning by using Ar ions, and then performing vacuum evaporation on an Al layer.
Further, the cleaning time of Ar ion bombardment in the step (1) is 10-30 min.
Furthermore, the vacuum evaporation time in step (1) is 10-60min, the evaporation current is 2000-3000A, and the thickness of the Al coating is 8-25 μm.
Furthermore, the grinding ball component in the step (2) can be one or a mixture of more of alumina ceramics, zirconia ceramics and zirconia toughened alumina ceramics.
Further, the diameter of the grinding ball in the step (2) is 1-5 mm.
Further, the mass ratio of the grinding balls to the sintered NdFeB magnet evaporated with the Al coating in the step (2) is 1: 2-10.
Further, the rotating speed of the ball mill in the step (2) is 50-300 r/min.
Further, the ball milling time in the step (2) is 10-120 min.
The sintered NdFeB magnet obtained by the preparation method has a densified Al coating on the surface.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the sintered NdFeB magnet and the grinding balls of the evaporated Al coating are put into a ball mill for ball milling, so that the evaporated Al coating has higher density, lower porosity and higher surface hardness, and thus has better corrosion resistance and mechanical damage resistance. The method solves the problems of low compactness, poor corrosion resistance and the like of the Al coating evaporated on the surface of the magnet, realizes the densification of the evaporated coating on the basis of keeping high bonding force between the evaporated coating and a substrate, and provides a longer-acting corrosion protection effect for the sintered NdFeB magnet.
Drawings
FIG. 1 is an SEM topography of a vacuum-evaporated Al coating on the surface of an NdFeB magnet;
FIG. 2 is an SEM topography of the surface densified Al coating of the NdFeB magnet prepared in example 1;
(As can be seen from FIGS. 1-2, the columnar crystal structure of the Al coating is tighter and the number of gaps and holes is greatly reduced after ball milling.)
Fig. 3 is an electrochemical polarization curve for NdFeB magnet surface vapor deposition of Al coatings and densified Al coatings prepared in examples 1, 2, 3, and 4.
Detailed Description
The present invention is further described with reference to the following examples, which are intended to be illustrative and illustrative only, and various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the claims.
The present invention will be described with reference to specific examples.
Example 1
(1) Preparation of PVDAl coating: loading the magnet subjected to pickling pretreatment into a furnace, vacuumizing, cleaning for 20min by Ar ion bombardment, then carrying out vacuum evaporation on an Al layer at the evaporation current of 2500A for 20min, and taking out the sample after completion.
(2) And (3) placing the NdFeB sample coated with the Al coating into ethanol and deionized water respectively, ultrasonically cleaning for 5min, drying and storing for later use.
(3) High-energy ball milling: 360g of ZrO were weighed with an electronic balance2Putting the grinding balls into a 500mL ball milling tank, weighing 18g of the sample obtained in the step 2), putting the sample into the tank for grinding, adjusting the rotating speed of the ball mill to be 300r/min, grinding for 30min, taking out the sample after finishing grinding, washing the sample with deionized water, and drying to obtain the Al coating with the densified surface.
Comparative example 1 is an Al plating layer on the surface of an untreated sintered NdFeB magnet, having a surface Hardness (HV) of 100.3, a corrosion potential of-1.09V in an electrochemical corrosion test, and a self-corrosion current density of 179.60 μ A cm-2The salt spray resistance time is 48 hours;
the densified Al plating layer formed according to the above procedure had a surface Hardness (HV) of 116.5, a corrosion potential of-0.98V in an electrochemical corrosion test, and a self-etching current density of 2.73. mu.A.cm-2The salt spray resistance time is 168h, and the comprehensive corrosion resistance of the alloy is obviously better than that of the comparative example.
Example 2
The preparation method of this example is the same as example 1, except that the ball milling time in step (2) is 10 min.
The densified Al coating formed according to the above procedure was tested to have a surface Hardness (HV) of 106.5, a corrosion potential of-1.05V in an electrochemical corrosion test, and self-corrosionThe current density was 10.82. mu.A.cm-2The salt spray resistance time is 120h, and the comprehensive corrosion resistance of the alloy is obviously superior to that of the comparative example;
example 3
The preparation method of this example is the same as example 1, except that the ball milling time in step (2) is 60 min.
The densified Al coating formed according to the above procedure was tested to have a surface Hardness (HV) of 108.3, a corrosion potential of-0.87V in an electrochemical corrosion test, and a self-corrosion current density of 7.24 μ A cm-2The salt spray resistance time is 120h, and the comprehensive corrosion resistance of the alloy is obviously superior to that of the comparative example;
example 4
The preparation method of this example is the same as example 1, except that the ball milling time in step (2) is 120 min.
The densified Al coating formed in accordance with the above procedure was tested to have a surface Hardness (HV) of 112.3, a corrosion potential of-1.06V in an electrochemical corrosion test, and a self-corrosion current density of 9.49 μ A cm-2The salt spray resistance time is 144h, and the comprehensive corrosion resistance of the alloy is obviously better than that of the comparative example.
Example 5
The preparation method of this example is the same as example 1, except that the ball mill rotation speed in step (2) is 200 r/min.
The densified Al coating formed in accordance with the above procedure was tested to have a surface Hardness (HV) of 105.4, a corrosion potential of-1.04V in the electrochemical corrosion test, and a self-corrosion current density of 11.19 μ A cm-2The salt spray resistance time is 136h, and the comprehensive corrosion resistance of the alloy is obviously better than that of the comparative example.
Example 6
This example was prepared in the same manner as example 1, except that the mass of the grinding ball in the step (2) was 200 g.
The densified Al coating formed according to the above procedure was tested to have a surface Hardness (HV) of 109.3, a corrosion potential of-1.10V in an electrochemical corrosion test, and a self-corrosion current density of 26.60 μ A cm-2The salt spray resistance time is 108h, and the comprehensive corrosion resistance of the alloy is obviously better than that of the comparative example.
Claims (10)
1. A preparation method of a sintered NdFeB magnet surface densified Al coating is characterized by comprising the following steps: the method comprises the following specific steps:
(1) preparing an Al coating: preparing an Al coating on the surface of the sintered NdFeB magnet by adopting vacuum evaporation;
(2) high-energy ball milling: and putting the sintered NdFeB magnet with the Al coating evaporated and the grinding balls into a ball milling tank for ball milling, taking out the sintered NdFeB magnet after ball milling, cleaning and drying to finish the surface densification of the Al coating.
2. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 1, wherein the method comprises the following steps: the specific preparation method of the Al coating in the step (1) is as follows: and (3) loading the magnet subjected to acid cleaning treatment into a furnace, vacuumizing, performing bombardment cleaning by using Ar ions, and then performing vacuum evaporation on an Al layer.
3. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 2, wherein the method comprises the following steps: in the step (1), the Ar ion bombardment cleaning time is 10-30 min.
4. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 2, wherein the method comprises the following steps: in the step (1), the vacuum evaporation time is 10-60min, the evaporation current is 2000-3000A, and the thickness of the Al coating is 8-25 μm.
5. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 1, wherein the method comprises the following steps: the grinding ball in the step (2) can be one or a mixture of more of alumina ceramics, zirconia ceramics and zirconia toughened alumina ceramics.
6. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 1, wherein the method comprises the following steps: the diameter of the grinding ball in the step (2) is 1-5 mm.
7. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 1, wherein the method comprises the following steps: the mass ratio of the grinding balls to the sintered NdFeB magnet with the Al coating evaporated in the step (2) is 1: 2-10.
8. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 1, wherein the method comprises the following steps: the rotating speed of the ball mill in the step (2) is 50-300 r/min.
9. The method for preparing the sintered NdFeB magnet surface densified Al coating according to claim 1, wherein the method comprises the following steps: the ball milling time in the step (2) is 10-120 min.
10. A sintered NdFeB magnet surface densified Al coating obtained by the production method according to any one of claims 1 to 9.
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Cited By (4)
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|---|---|---|---|---|
| CN112342576A (en) * | 2020-10-27 | 2021-02-09 | 合肥工业大学 | Densification method for sintered NdFeB magnet surface metal coating |
| CN114360889A (en) * | 2022-02-11 | 2022-04-15 | 安徽大地熊新材料股份有限公司 | Preparation method and application of sintered neodymium-iron-boron magnet surface aluminum coating |
| CN114717511A (en) * | 2022-03-30 | 2022-07-08 | 北矿磁材（阜阳）有限公司 | Preparation method of Al film on surface of sintered neodymium-iron-boron magnet |
| CN114360889B (en) * | 2022-02-11 | 2024-04-26 | 安徽大地熊新材料股份有限公司 | Preparation method and application of aluminum coating on surface of sintered NdFeB magnet |
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| CN114360889B (en) * | 2022-02-11 | 2024-04-26 | 安徽大地熊新材料股份有限公司 | Preparation method and application of aluminum coating on surface of sintered NdFeB magnet |
| CN114717511A (en) * | 2022-03-30 | 2022-07-08 | 北矿磁材（阜阳）有限公司 | Preparation method of Al film on surface of sintered neodymium-iron-boron magnet |
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