JPS62101008A - Magnetic member - Google Patents

Abstract

PURPOSE:To improve heat resistance by dispersing a specific quantity of crystallites having particle size of approximately 0.1mum or less approximately uniformly into mother phase consisting of an amorphous body. CONSTITUTION:A pseudo-crystalline material is arranged in at least one part of a section requiring excellent magnetic characteristics as well as heat resistance, abrasion resistance, etc. The pseudo-crystalline material uses an amorphous body as mother phase, crystallites having particle size of approximately 0.1mum or less are dispersed approximately uniformly extending over the whole in the pseudo-crystalline material, and the whole volume of the crystallites is made the same as or larger than the volume of the amorphous body. A magnetic member is acquired by thermally treating a thin-film material obtained through sputtering, etc. for approximately one hr at a low temperature (300-500 deg.C), thus eliminating the thermal instability of an amorphous magnetic material, then improving the heat resistance of the material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an amorphous magnetic member constituting at least a part of a magnetic circuit, and is widely used in various electronic parts and electronic equipment fields.

BACKGROUND OF THE INVENTION Many materials and manufacturing methods are generally known for amorphous magnetic materials. For example, ribbon-shaped amorphous film formation technology M using ultra-quenching method, Kikuchi et al. + Jpn.

■, Applied Physics (M, Kikuchi.

etal, , Jpn, J, Appl, Phy
s-, 14, 1077 (1975)), thin film formation technology by sputtering method M, Nose et al., ■, Applied Physics (M.

No5e, etal, , 1. Appl, Ph
ys, 52, 1911 (1981)), etc.
Amorphous magnetic materials have been produced. As is well known, these amorphous materials have properties that other crystalline materials do not have because they are amorphous.

For example, although it has excellent corrosion resistance and wear resistance, it is known that once crystallization begins, its properties become extremely poor.

For example, according to patent USP No. 4,079,430, if the amount of crystalline material is approximately 50% or less, it can be used even if the characteristics deteriorate. However, these basically amorphous magnetic materials are known to be
Experiments conducted by the inventors have shown that it is very thermally unstable and deteriorates after heat treatment at a low temperature of 300 to SOO°C for about 3 hours. At this time, when the material is observed in detail using an electron microscope, etc., it can be seen that large particles of 0.2 to 1 μm are generated throughout the material.Problems to be solved by the inventionAs is partially clear from the above explanation, In addition, amorphous materials have poor thermal stability, and therefore various problems arise in heat treatment when manufacturing electronic components and the like using these materials. Furthermore, in use, due to poor heat resistance, various heat countermeasures such as heat radiation and insulation are required, and long-term reliability is problematic.

The present invention provides a magnetic member that solves the problem of heat resistance.

Means for Solving the Problems A condensed crystalline material is placed in at least a portion of the parts that require excellent magnetic properties as well as heat resistance and abrasion resistance.

The coagulated crystalline material has an amorphous matrix, in which microcrystals having a grain size of approximately 0.1 μm or less are almost evenly dispersed throughout, and The volume of the amorphous material is equal to or larger than the volume of the amorphous material.

Function Homogeneously dispersed microcrystals become nuclei for homogeneous grain growth,
That is, as a result of preventing abnormal grain growth and structural changes, it has the effect of preventing changes in magnetic properties that are sensitive to changes in fine structure.

EXAMPLE A magnetic member according to the present invention is produced by first heat-treating a thin film material obtained by sputtering or the like at a low temperature (300°C to 500°C) for about 1 hour, and further processing (cutting, polishing, etc.) required for electronic equipment. glass bonding and reheat treatment).

As a result, a coagulated crystalline material is formed in which the above-mentioned microcrystals are evenly distributed throughout.

contains.

The nature of the thermally stable coagulated crystalline material used in the magnetic member of the present invention is largely unknown, and much remains to be investigated in the future.

However, based on the experimental results of the inventors, the following effects are considered.

Generally, amorphous materials are thermally unstable and are considered to be in a supercooled glass state that crystallizes when heated. Although such an amorphous material is amorphous, as shown in Figure 2,
Microscopically, the amorphous body 1 contains countless microscopic crystal nuclei 2ai called embryos, but of various sizes. Good for heating.

Among these embryos, those under certain conditions grow and continue to grow as crystal nuclei. At this time, strain occurs in the periphery due to volume changes, etc., and the growth is further accelerated. Therefore, in general amorphous materials, as shown in Figure 2, 0.2
So-called abnormal grain growth including abnormally large crystals 3 up to 1 μm in size can be observed. Furthermore, even if there is a large local strain or a lump of impurities in the material, so-called non-uniform nucleation occurs, resulting in a double grain size distribution structure as shown in FIG.

The material in the present invention is also considered to be in an unstable state as described above immediately after formation. However, by short-term heat treatment at 300-600°C (1-3 hours), the above-mentioned local strains are annealed, eliminating heterogeneous nucleation and changing the shape distribution of the embryo to a stable shape. As shown in FIG. 1, microcrystals are uniformly dispersed in the amorphous body 1. Therefore, it is thought that abnormal grain growth and structural changes due to minute structural relaxation at low temperatures are prevented. In general, as shown by the solid line (a) in Figure 3, there are countless small embryos, and the larger the embryo, the smaller the number of embryos. Its size is generally several people,
It is estimated that 100 people will grow. At this time,
When heat treatment is performed, the critical diameter (b) determined by the temperature
The following Embryos will disappear and the above Embryos will begin to grow. Therefore, after a certain period of time, the distribution becomes as shown by the dotted line.

As a result, small embryos that are sensitive to heat treatment disappear or are greatly reduced, while some large embryos that are insensitive remain. Therefore, it is considered that the material is extremely stable against subsequent heat treatment. As is clear from the above description, this effect is particularly noticeable in materials that are particularly easy to crystallize, for example, in compositions close to the amorphous-crystalline boundary in the phase diagram.

When the precipitated crystalline material of the present invention described above is heat-treated at a temperature higher than the crystallization temperature, embryos of a certain size are evenly distributed, and as is clear from observation with an electron microscope, the material composition changes. However, a double particle size distribution structure is not obtained, and a uniform particle structure of approximately 0.1 μm or less is obtained.

Example V will be explained in more detail below.

"8O-9ONb10-152r3-8Ta2-7 targets with various compositions were prepared and sputtered in Ar gas to form a thin film material with a thickness of 51 trn on a glass substrate.The sputtering conditions were: Ar gas pressure 2× 1O-2To
rr, 13.45 MHz rf input 400W, target distance approximately 4crR, substrate water cooling (26℃),
The glass substrate has a thermal expansion coefficient of 110X with little thermal distortion.
A crystallized glass having a molecular weight of 10-7 was used.

- Figure 4 shows the results of a typical transmission electron diffraction experiment.

Immediately after forming a thin film, even in materials exhibiting a Debye-Scherer ring, which indicates a state that is not completely amorphous, aOO℃
After a primary heat treatment of 1 hour, it was found to be very stable even after several hours of heat treatment at 480° C., with no change in magnetic properties for approximately 6 hours. The state of the electron diffraction rings has become somewhat clearer than the original Devine-Eller rings during the first and subsequent heat treatments, but no major changes have occurred. ,
For example, in heat treatment at 700°C for 1 minute, Q,
It is polycrystalline with a grain size of 1 μm or less, and
A very clear electron diffraction pattern was obtained. Diffraction intensity is obtained by blackness analysis of this diffraction photograph. This strength indicates a crystalline portion, with almost no contribution from the amorphous parent phase, and since these are the same composition as Material 9, it is considered to be proportional to the volume of the crystalline portion.

When the ratio of the total volume of microcrystals to the volume of the amorphous matrix was calculated using the above method, both were 1.0 or more.

Table 1 shows experimental results under various formation conditions, including the representative examples above.

To evaluate the film, first, immediately after formation, an electron diffraction image is observed.

Table 1 shows those with a complete halo shape.

Those containing a Debye-Schierer ring are indicated by Q. Next, annealing was performed by preheating treatment at SOO℃ for 1 hour, and the electron diffraction image was observed again.
Further, by transmission electron microscopy, the state where there are no particles (including those with unclear contrast) is shown as a,
Those containing abnormal particles were designated as iD. At this time, the initial magnetic permeability (1 MHz), which is highly sensitive to structure, was measured as a magnetic property.

Next, after conducting a long-term heat resistance test at 480° C. for 5 hours, the initial magnetic permeability was measured again. Its rate of change (rate of decline) 30
% or less is defined as A, 50% or less is defined as B1 or more is defined as C, and the first
The results are shown in the table. Further, a complete crystallization heat treatment was performed at 700° C. for 1 minute, and the state of crystallization was observed. Those with uniform grain growth were labeled with S, and those with a double structure with abnormal growth were labeled with Di, as shown in the table.

In addition, the column of prognosis shows the volume ratio of crystalline/amorphous matrix. For halo-shaped particles, the ratio was set to 0.5 or less. For reference, the first column shows the sputtering pressure during formation (
10-3 Torr).

As can be seen from Table 1, those having a volume ratio of more than 1.0 are shown to have good heat resistance. Furthermore, in these materials, the grain size after annealing is 0.
It was also observed that it was less than 1 μm. For other items, it was 0.2 to 1 μm.

In this example, the above-mentioned materials and compositions are shown, but since it is considered to be based on the principle explained in the previous section 9, the present principle can be applied to other similar materials. That should be obvious.

Next, for the material of evaluation A in Table 1, the temperature was 40°C.

When an 80% humidity test was conducted for 1000 hours, it showed good corrosion resistance no different from conventional amorphous materials.

Further, as shown in FIG. 6, a layer 4 of a precipitated crystalline material according to the present invention having a thickness of 5 μm is placed through an insulating film 5 of 8102.
Eight layers (not shown) are laminated on the substrate e to a total thickness of about 30 μm, then the same substrate 6 is bonded, and after cutting and other processing,
A magnetic head having a magnetic gap 7 with a length of 4 μm was formed. In this process, 6o heat treatment that also serves as annealing and glass sealing treatment are performed.

C. for 1 hour and 480.degree. C. for 30 minutes.

Attach this magnetic head to a VH3 type VTR to generate a 6MHz
The standard output was measured, and this was taken as the standard odB. Next, the same magnetic head was heat-treated at 480° C. for an additional 2 hours, and its output was measured, and it was found that all outputs were within ±1 dB, indicating that there was little change in the output.

Next, we conducted similar tests on B-rated and C-rated materials, and each found an average of about 3 dB.

It was found that there was a decrease in output of cs dB.

Although such a high temperature environment is not an actual general use environment,
As a result, the resulting thermal stability leads to an improvement in production yield and stabilization of crystallinity, which further improves long-term reliability.

Furthermore, it is estimated that the tip of the magnetic head is at a high temperature due to contact with the tape, and even in this local area, improved heat resistance helps maintain magnetic properties and prevent spacing loss.

Although the above examples are limited to only limited materials and compositions, it goes without saying that the principles of the present invention are equally applicable to other material compositions.

A member similar to local heating of the tip of a magnetic head, for example,
It goes without saying that K can also be applied to anti-radio wave reflection coatings on the tips of supersonic jet aircraft, and has the same effect.

Effects of the Invention According to the present invention, the thermal instability of an amorphous magnetic material is eliminated, and the heat resistance of the material is greatly improved.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the outline of the microstructure of the coagulated crystalline material in the present invention, and Fig. 2 is a cross-sectional view showing the microstructure and double grain size distribution structure of the material exhibiting poor magnetic properties observed after heat treatment. , Figure 3 is a graph showing the embryo distribution and its changes, Figure 4 is a diagram showing an example of an electron diffraction diagram, and Figure 5 is a graph showing an example of an electron diffraction diagram.
The figure is a cross-sectional view schematically showing a magnetic head that is an embodiment of the present invention. 1... Amorphous body, 2... Microcrystalline.

Claims (1)

[Claims] A coagulated crystal in which microcrystals with a grain size of approximately 0.1 μm or less are almost evenly dispersed in a matrix composed of an amorphous substance, and the total volume of the microcrystals is greater than or equal to the volume of the matrix. quality materials,
A magnetic member characterized in that it is used for at least a part of a magnetic circuit.