JPS6152371A - Surface treatment of thin amorphous magnetic metallic strip - Google Patents

Abstract

PURPOSE:To prevent the deterioration in magnetic characteristic owing to a surface treating film by spraying a molten metal onto a cooling body under high-speed rotation to form a thin amorphous magnetic metallic film and spraying a surface treating agent to the surface thereof immediately after such formation. CONSTITUTION:The molten metal M which is an Fe magnetic alloy in a crucible 3 is sprayed from a nozzle 5 onto a rotary roll 1 made of a copper alloy having excellent heat conductivity while said roll 1 is rotated at a high speed to form the thin strip of the amorphous alloy by quick cooling on the roll surface. The pulverous powder C of alumina as the surface treating agent in a spraying device 11 is atmized onto the surface of the thin amorphous magnetic metallic strip from a nozzle 12 right after said formation to form the thin film of the surface treating agent. The coefft. of the thermal expansion of the thin film by the surface treating agent is extremely smaller than the coefft. of themal expansion of the thin amorphous magnetic metallic strip and therefore the residual tensile strain is generated in the thin metallic strip as a result of a difference in the coefft. of thermal expansion in the cooling stage of the thin strip and the thin film, by which the deterioration of the magnetic characteristic of the thin amorphous magnetic metallic strip is obviated and said characteristic is rather improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for surface treatment of an amorphous magnetic metal ribbon having excellent magnetic properties.

(Prior Art) An amorphous negative metal (alloy) ribbon (plate) produced by rapid solidification from molten IE exhibits various excellent properties and is attracting attention for applications. Among these, Fe-based amorphous alloys have a high saturation magnetic flux density and low iron loss, and are therefore being used as materials for various iron cores. The reason why Fe&amorphous alloy has low core loss is that it has no anisotropy and has no defects such as grain boundaries, so hysteresis loss is low.

In this way, Fe amorphous metal is originally a material with excellent magnetic properties, but because it is thin, when surface treatment is performed, the thin ribbon and the surface film formed on it by surface treatment are The magnetic properties are affected by the distortion caused by the interaction, and the magnetic properties deteriorate. That is, an amorphous magnetic metal ribbon has a small coefficient of thermal expansion, and therefore a glassy coating such as a normal chromate treatment is subjected to compressive stress after cooling, and its good magnetism deteriorates.

Therefore, conventionally, surface treatment was not performed.

Under these circumstances, if it were possible to form a ceramic film with a low coefficient of thermal expansion, it would be possible to apply tension to the surface of the amorphous magnetic metal ribbon and at least prevent deterioration of magnetism. , further improvement in magnetism can be expected in some cases.

Also, as mentioned above, surface treatment is not normally performed, but even if surface treatment was performed, it is assumed that the surface treatment was performed after the ribbon was once cast and cooled. be done.

Furthermore, since amorphous metals tend to crystallize when the temperature is raised, the above-mentioned surface treatment must be performed at a temperature below the crystallization temperature, so it is necessary to use a ceramic-based surface treatment agent with a low coefficient of thermal expansion. However, although this method is not impossible, it is not very effective.

(Problems to be Solved by the Invention) The present invention aims to solve the above-mentioned problems and effectively perform surface treatment on an amorphous magnetic metal ribbon to improve its magnetic properties. .

(Means for solving the problem) The present invention injects molten metal onto the surface of a moving cooling body,
In the method of producing a metal ribbon by rapid solidification, a film is formed on the surface of the amorphous magnetic ribbon by spraying a surface treatment agent onto the surface of the ribbon following the injection of the molten metal. This is a characteristic feature.

For example, as shown in FIG. 1, the amorphous metal ribbon for carrying out the method of the present invention is produced from a nozzle 5 provided on the bottom surface of a crucible 3 placed directly on the surface of a roll l rotated by a drive M2. Although it is produced by spouting molten metal M and rapidly solidifying it, in the present invention, the nozzle 5
A device 11 is disposed in the surface treatment agent blowhole storing the surface treatment agent C adjacent to the surface treatment agent C, and a nozzle 12 is provided at the bottom of the blowhole, so that the molten metal M is spouted from the nozzle 5. When the ribbon is formed, the surface treatment agent C is sprayed from the surface treatment agent spraying device 11 onto the surface of the ribbon, so that the surface treatment agent C is baked onto the surface of the ribbon to form a film.

Note that FIG. 2 shows an example of the shape of the opening 6 of the nozzle 5. FIG. 2(a) is suitable for producing a wide ribbon, and FIG. Suitable for producing thin ribbons.

The surface treatment agent used in the present invention is a liquid or a powder, and will be explained by giving an example.

As a colloidal insulating oxide, for example 1 to 20% by weight of ethyl silicate is added to a mixture of MgO, A203.5i02.

This ethyl silicate is hydrolyzed to form active 5i02
The above-mentioned colloidal metal oxide is wrapped as. When these are applied in a spray state from the surface treatment agent spraying device 11, the mixture is dried and baked by the heat of the ribbon. Then, the 5i02 that has just been generated by the hydrolysis of ethyl silicate promotes a bonding reaction with the applied oxides and with metal oxides such as S+02 formed by oxidation on the surface of the ribbon.

In addition to the above tA composition, 0.2 to 5z by weight of a Li compound (Li carbonate, hydroxide, alcohol compound, etc.)
By adding , the bonding between 5i02 formed on the thin and smooth surface and the coated oxide is further promoted.

Examples of other surface treatment agents include Li and Mg.

Sentence A, alcohol compound 1 of Si, Ti or Zr
There are species or mixtures of two or more species. Further, fine powder of metal oxides produced by hydrolyzing and drying these alcohol compounds can also be used.

When these are sprayed or smoked onto the surface of the ribbon and dried and baked using the heat of the ribbon, active metal oxides produced by decomposition of the alcohol compound and oxidized 5.
i02 or other oxides combine to form a low expansion coefficient insulating oxide, which adheres to the surface of the ribbon.

Alternatively, the ribbon or the cooling body may be grounded, and the surface treatment agent may be sprayed by electrostatic application by applying a negative high voltage to the apparatus side.

(Function) The coefficient of thermal expansion of a film produced by a surface treatment agent such as L is smaller than that of an amorphous metal ribbon, so when the ribbon and film are cooled, the coefficient of thermal expansion decreases. The difference causes tensile residual strain in the ribbon. As a result, the magnetic domains are segmented, iron loss is reduced, and magnetic properties are improved.

(Example) Next, an example will be given and explained.

Example The method of the present invention was carried out using the apparatus shown in FIG.

Roll 1 is made of prepared alloy and has a diameter of 100100 (1φ, width 20
0 mm and rotated at a speed of 450 rpm. With this device, one composition Fe, o, g S i <, r B1
2C+ (at X) (7) Alloy 2nd U) 4(b
Triple slot-like opening (Illll) as shown in )
i d O, 4am, length 150mm, interval a1m
m) was used to cast into a thin strip. - As a blade surface treatment agent, a powder of A-203 produced by hydrolyzing and drying the butyl alcohol compound of Ai was sprayed onto the surface of the ribbon using N2 gas using a device. The skin 112 visit star after cooling is 0.5-0.7
g/m' Tea Tsuta.

Thin strip produced as described in L (average thickness 65 μm)
Approximately 2 kg was wound around a winding frame with an outer diameter of 120 mm at a tension of 2 kg to form a wound core. This wound iron core was heated to 370℃ for 2
It was annealed in a stream of N2 gas while applying a magnetic field of about 15 oersted for an hour. The measured magnetic properties of this core are the first
It was as shown in the table.

As a comparative example, Table 1 shows a thin strip manufactured with the same composition and under the same conditions as the E-arrangement sample material, but without surface treatment, and having the same shape, nine dimensions, and annealing conditions as the sample material.

As is clear from this table, it is clear that the iron core using the ribbon manufactured by the method of the present invention has lower core loss and superior magnetic properties than the comparative material. In addition, there is almost no deterioration in excitation effective VA, which normally occurs due to coating treatment.

Table 1 * 1 large. : Iron loss value at a frequency of 50 Hz and magnetic flux sound intensity of 1.3 Tesla. Since the film can impart residual tensile strain to the amorphous metal ribbon and subdivide the magnetic domains, it is possible to further improve not only the interlayer insulation but also the magnetic properties.

Further, since the surface treatment agent is sprayed subsequent to the spraying of the molten metal, the surface-treated amorphous magnetic metal ribbon can be continuously and efficiently manufactured.

Furthermore, the method of the present invention does not require a separate coating treatment step unlike the conventional method, and therefore the process can be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is a bottom view showing the shape of a nozzle opening. 1... Roll, 3... Crucible, 5... Nozzle, 6
...Nozzle opening, 11...Surface treatment agent spraying device, 12...Nozzle, C...Surface treatment agent, M...
molten metal.

Claims (1)

[Claims] A method for producing a metal ribbon by spraying molten metal onto the surface of a moving cooling body and rapidly solidifying the metal, characterized in that a surface treatment agent is sprayed onto the surface of the ribbon following the injection of the molten metal. Surface treatment method for crystalline magnetic metal ribbon.