JPS639906A - Magnet - Google Patents

Abstract

PURPOSE:To improve anticorrosion properties and chemical resistant properties which are weak points of a rare-earth iron magnet by a method wherein the rare-earth iron magnet is covered with metallic or compound films and pin-holes in the films and cavities in the magnet are sealed with resin. CONSTITUTION:The surface of a rare-earth iron magnet is covered with metallic, nonmetallic and compound films by physical vapor deposition (PVD) such as sputtering and ion plating or chemical vapor deposition (CVD) which is utilizing thermal decomposition or plasma decomposition of metal halide and pin-holes in films 2 and 3 and gaps 5 and 6 and cavities 4 in grain boundaries which are created when the magnet is sintered are sealed with resin. Therefore, after an object to be treated is degreased by organic solvent such as alcohol and trichloroethylene, the object can be cleaned in a treatment equipment by surface etching which is called ion-bombardment so that treatment and film formation can be performed without damaging the surface and internal defects and, moreover, defects such as pin-holes created when the films are formed and cavities and gaps created when the magnet is sintered can be eliminated. With this constitution, anticorrosion properties and chemical resistant properties can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to surface treatment of rare earth iron magnets.

(Summary of the Invention) This invention provides physical vapor deposition (P
VD: Physical Vapor mouth epO3
chemical vapor deposition (CV D: C
Rare earth iron-based magnets are coated with a film of metal, non-metal, or compound using chemical vapor deposition, and the pinholes in the film and the voids and pores in the grain field that occur during magnet sintering are sealed with resin. The purpose is to improve corrosion resistance and chemical resistance.

(Prior art) Conventionally, S+n-Co based magnets have been widely used as rare earth magnets, but rare earth iron based magnets such as Nd-Fe based magnets are used, which are advantageous in terms of manufacturing cost, magnetic properties, etc. Momentum is increasing.

However, rare earth iron-based magnets are inferior to Sm-co-based magnets in terms of corrosion resistance and chemical resistance, and are prone to discoloration, rust, etc., and require protection through some kind of surface treatment. .

(Problem to be solved by the invention) Rare earth iron magnets are poor in corrosion resistance and chemical resistance.

Therefore, the first surface treatment to improve corrosion resistance! I! When performing plating, etc., if chemicals such as acids and alkalis used for plating etc. are used, the surface and internal defects (holes, etc.) of the magnet will be attacked during the treatment process, making it difficult to perform the desired treatment. Ta. Coating, sealing, and sealing with organic materials such as resins and polymer compounds are also being considered, but! ! ? It has the disadvantage that it is difficult to put it into practical use due to its low Ii properties and low mechanical strength.

The present invention solves the above-mentioned drawbacks and provides a rare earth iron magnet having high magnetic properties with excellent corrosion resistance, chemical resistance, and mechanical strength on the surface.

(Means for solving the problems) In order to solve the above problems, films of metals, non-metals, and compounds are formed using PVD methods such as vacuum evaporation, sputtering, and ion blasting, and CVD methods using decomposition reactions of halogen compounds. Corrosion resistance and chemical resistance are improved by sealing and sealing defects such as pinholes that occur during coating formation and voids and voids that occur during magnet sintering using resin.

(Function) In gas phase plating using the PVD method or CVD method, it is possible to degrease the processed material with an organic solvent such as alcohol or trichlorethylene, and then clean it by surface etching called ion bombardment in the processing equipment. When processing rare earth iron magnets that have poor chemical resistance, there is no need for pretreatment with acid or alkaline solutions, and these chemicals can be used to process and form films without damaging the surface or internal defects. can. Furthermore, defects such as pinholes created during film formation by vapor phase marring and voids and voids created during magnet sintering can be sealed and sealed by coating and impregnating with resin to eliminate the above-mentioned defects. Can be done.

(Example 1) The present invention was applied to a rotor for an electronic watch formed from a sintered alloy for Nd-1''6-3 type magnets as a rare earth iron type magnet.

First, the rotor was degreased and cleaned with trichlorethylene, and a titanium nitride film was formed on the rotor surface in about three directions using metallic titanium and nitrogen gas by reactive ion blating using a three-electrode direct current system, which is a typical PVD method. At this time, after cleaning with trichlorethylene, the rotor surface was cleaned by sputter cleaning using ion bombardment using argon gas discharge in the film deposition apparatus prior to film deposition.

Next, the processed material (
The rotor (on which a titanium nitride film was formed) was ultrasonically cleaned with trichlorethylene, and then coated with polyparaxylylene. With this polyvaraxylylene coating, for example, Tomoe Kogyo's parylene coating,
Pinholes in the titanium nitride film, holes and voids in the magnet were sealed and sealed. After the titanium nitride film was formed and before the parylene coating, ultrasonic cleaning was performed to remove powdery substances that adhered during and after the titanium nitride film was formed. There is no need to do this.

As shown in the cross-sectional view of the magnet shown in Figure 1, the magnet treated in this way has its surface, pores, and voids completely covered with a titanium nitride film and a parylene coat film. , No discoloration after 100 hours constant temperature and humidity test.

No defects such as rust occurred.

(Example-2) As in Example-1, after forming a titanium nitride film on the rotor,
Anaerobic resin was used for sealing and sealing.

Specifically, as the anaerobic resin, Loctite, an acrylic ester resin manufactured by Nippon Loctite ■, was used. As a method, first, the rotor on which the titanium nitride film was formed is immersed in Loctite before hardening. Next, this rotor was taken out and left in a vacuum of about 1 Torr for about 5 minutes to harden the Loctite in the pinholes, holes, and voids. At this time, by controlling the degree of vacuum and time, it is possible to prevent the Loctite on the titanium nitride film from hardening, and it can be removed later with a solvent such as alcohol, leaving only defects such as pinholes, holes, and voids. I was able to leave the hardened Loctite resin behind. Figure 2 is a cross-sectional view of a magnet subjected to this treatment, and shows that the magnet surface and defective parts can be completely protected by coating, and no defects were observed in the constant temperature and humidity test as described in Example-1. Furthermore, there was no peeling or falling off when the O-ta and Kana were combined.

(Effects of the Invention) As described above in the examples, according to the present invention, it is possible to overcome the defects of rare earth iron magnets, such as poor corrosion resistance and chemical resistance, and The uses of magnets can be expanded.

In addition, in the examples, Nd-
Although I have described Fe-B magnets, similar effects can be obtained with other magnets, and although a titanium nitride film has been cited as an example of the film, other metals may be used depending on the purpose.

Needless to say, non-metals and compounds can be applied.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of a magnet according to an embodiment of the present invention. 1... Nd-Fe-B magnet 2... Titanium nitride film 3... Polyparaxylylene film 4... Hole in magnet 5... Pinhole in titanium nitride film 6... Poly Pinhole 7 in baraxylylene film...
Anaerobic resin that seals and seals pinholes, holes, and voids

Claims (1)

[Claims] Dry plating method (vapor plating method) on the surface of rare earth iron magnets
1. A magnet characterized by being coated with a metal or compound film made of a metal or a compound film, and having film pinholes and pores inside the magnet sealed with a resin.