JPS6340624B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a thick Fe-based amorphous alloy ribbon produced by a method of rapidly solidifying a metal (alloy) in a molten state on the surface of a moving cooling substrate. be. (Prior Art) The basic methods for continuously producing thin ribbons by rapidly cooling metals (alloys) from a molten state include the centrifugal quenching method and the melt spinning method represented by the single roll method.
In this method, a jet of molten metal is jetted onto the inner or outer peripheral surface of a rotating metal drum and rapidly solidified, thereby creating a metal ribbon or wire all at once.
According to this method, the cooling rate is extremely fast, so if the alloy composition is appropriately selected, an amorphous metal (alloy) having a structure similar to that of liquid metal can be obtained. Amorphous metals (alloys) are metal materials that have attracted practical attention due to their unique properties, but the range of applications has been limited by the fact that only thin plates can be manufactured due to constraints on cooling rates. Generally, the maximum thickness of an amorphous alloy depends on the alloy composition and the cooling capacity of the device. The composition dependence of the plate thickness that can be made amorphous has been investigated mainly for iron-based alloys, which are of practical importance, as reported by Hagiwara et al., Sci.Rep, Res.
According to Inst. Tohoku Univ. A-29 (1981), 351, the iron-based metalloid alloy that is most likely to become amorphous is
For Fe-Si-B and Fe-P-C based alloys, the maximum plate thickness is reported to be 250 μm for Fe ₇₅ Si ₁₀ B ₁₅ in the case of Fe-Si-B. However, this method takes special measures to slow down the rotation speed by suddenly applying a brake on the rotation of the cooling substrate (roll) in order to obtain a thick sample. It has also been revealed that thick amorphous ribbons can only be obtained under such unsteady conditions, with no amorphous material being obtained. Therefore, it is clear that the material obtained by the method of Hagiwara et al. is not an industrially usable material. Moreover, the value of the maximum plate thickness of 250 μm in this report is disputed. Namely, the report by Luborsky et al. IEEE Trans.Magnetics, MAG-18 (1982)
According to 1385, the maximum thickness that can be obtained in a substantially completely amorphous Fe-Si-B alloy is Fe ₇₄ Si ₁₀ B _16.
It is stated that the coercive force increases, which is thought to be due to the formation of microcrystals, when the plate thickness increases beyond this value of 42 μm. Luborsky et al.
Regarding the discrepancy in results with Hagiwara et al.
Hagiwara et al. used an optical microscope (100x magnification) to determine amorphization, and point out that even minute amounts of crystals that cannot be detected with an optical microscope can degrade properties such as magnetism. If Luborsky et al.'s theory is correct, then
The 250 μm thick amorphous material reported by Hagiwara et al. contains microcrystals, which are not observed under an optical microscope, but which degrade the properties. Also, even if Hagiwara et al.'s thick sample were completely amorphous, their experiments were performed on a narrow sample, about 1 mm wide, and the same thickness cannot be guaranteed for a wider material. This is because in the case of a narrow material, the heat flow across the substrate is two-dimensional, whereas in the case of a wide material, the heat flow across the substrate is one-dimensional, and as a result, the cooling rate is significantly reduced. By the way, among amorphous alloys, Fe-based alloys are inexpensive, have excellent properties, and are extremely useful materials in practice, but because of their low amorphous formation ability, only thin materials can be obtained, and therefore they are extremely difficult to use. Even when used as a transformer core, which is considered useful, there were problems such as it could only be used in the form of a wound core. In any case, with current technology, the plate thickness is large and wide.
It has been considered difficult to industrially produce Fe-based amorphous alloy ribbons. (Objective of the Invention) The present invention provides a thick and wide Fe-based amorphous alloy ribbon that could not be achieved with the prior art as described above. (Structure and operation of the invention) The Fe-based amorphous alloy ribbon of the present invention is characterized by being wide and thicker than conventional ribbons. The plate thickness is at least 50 μm or more, and the width is at least
It is 20mm. Also, the plate thickness is at least 55μ
m, the width is also preferably at least 25 mm. The surface of the Fe-based amorphous alloy ribbon of the present invention is smoother on both the roll surface and the free surface than a ribbon produced by the conventional single roll method. Center line average roughness at a cut-off value of 0.8 mm measured in the width direction of the ribbon using the method specified in JIS B0601
As shown in Table 1, Ra was 0.5 μm or less on both the roll surface and the free surface. This value is smaller and superior than the conventional material, which has a roll surface of 0.6 to 1.3 μm and a free surface of 0.6 to 1.5 μm. Reflecting the large thickness and smooth surface, the amorphous alloy ribbon of the present invention has an extremely high space factor when laminated. While the space factor of conventional materials is 75 to 85%, the amorphous alloy ribbon of the present invention has a space factor of 85 to 95%. Despite the large thickness of the amorphous alloy ribbon of the present invention, there is no deterioration in properties. The reason is that even if the material is thick, it remains substantially amorphous throughout the entire thickness and thus retains properties unique to amorphous materials. For example, regarding magnetism, Fe _80.5 Si _6.5 B ₁₂ C ₁ (at
%) of 25μm thick, 25mm wide amorphous alloy ribbon at 50Hz
(Hertz), 1Oe (Oersted) magnetic flux density is 1.53T (Tesla), but with the same composition it is 65μ
The amorphous alloy ribbon of the present invention with a thickness of 50 mm and a width of 25 mm is
It shows the same 1.53T at Hz and 1Oe, and it is clear that there is no deterioration. Next, a method for producing the thick amorphous alloy ribbon of the present invention will be described. The amorphous alloy ribbon of the present invention can be produced by the following means that essentially increase the cooling rate. Molten metal ejected onto the surface of a moving cooling substrate as in the single roll method (or belt method) forms a puddle (hereinafter referred to as a puddle) on the substrate, and solidification progresses from the portion in contact with the substrate. A high solidification rate is required to obtain a large plate thickness. Conventional methods such as increasing the jetting pressure, reducing the moving speed of the cooling substrate, and increasing the gap distance between the nozzle and the substrate limit the thickness of the thin strip that can be produced (approximately 45 μm, However, if the width is 20mm or more), if you try to make the board thicker than that, the shape, surface quality, and properties will deteriorate.
Therefore, in order to obtain a thick plate without impairing the shape or properties, it is essentially necessary to take measures to increase the solidification rate. In order to increase the solidification rate, the present inventors applied the following method to produce a thick and wide amorphous alloy ribbon. The thick and wide amorphous alloy ribbon of the present invention is produced by a method that increases the cooling rate during solidification. That is, by a method having means for increasing the thermal contact between the alloy and the cooled substrate while the alloy is in an unsolidified state drawn from the paddle. Specifically, gas pressure or the pressure of the molten metal flow jetted from the second and third nozzle openings is used. There are two methods of using gas pressure: one is to apply pressure directly to the unsolidified free side of the alloy ribbon pulled out from the paddle, and the other is This method increases the pressure of the atmosphere surrounding the entire unsolidified ribbon including the paddle. The former method appears to be similar to previously proposed methods, such as the method described in US Pat. No. 3,862,658, but is completely different in the following points. In the conventional method, a gas pressure or an auxiliary roll (or belt) is pressed against the completely solidified amorphous alloy ribbon pulled out from the paddle. Therefore, it does not increase the solidification rate and it is not possible to produce a thick amorphous alloy ribbon. The second method is to make the entire atmosphere high pressure.
Since pressure is applied not only to the drawn amorphous alloy ribbon but also to the paddle itself, the solidification rate is further increased, making it easier to manufacture thick amorphous alloy ribbons. As a method that does not utilize gas pressure, there is a method that utilizes the pressure of the molten metal flow according to an invention by the present inventor (Japanese Patent Application No. 216,287/1987). In this method, the amorphous alloy ribbon drawn from one paddle is superimposed on a second paddle before it completes solidification.
The pressure applied by the second paddle increases thermal contact with the cooled substrate and increases the rate of solidification. By stacking the paddles one after another in this manner, it is possible to produce a thick amorphous alloy ribbon corresponding to the amorphous critical thickness of the alloy under the increased cooling rate. The amorphous alloy ribbon of the present invention is characterized not only by its large thickness but also by its excellent surface quality. As mentioned above, in order to obtain a thick plate, measures are taken to improve the thermal contact between the amorphous alloy ribbon and the cooling substrate, but this also reduces the size and number of bubbles that are drawn into the substrate surface. Reduce.
As a result, the substrate surface of the amorphous alloy ribbon has fewer dents caused by air bubbles that are characteristic of single-sided cooling methods such as the single-roll method.
and has less smooth surface texture. The effect of improved thermal contact between the amorphous alloy ribbon and the cooling substrate is also reflected in the surface texture of the free surface side. Since the non-uniformity of heat transfer within the puddle is reduced, the solidification interface becomes flat and, as a result, the free surface of the drawn amorphous alloy ribbon is also smooth. When the surface of the thick and wide amorphous alloy ribbon of the present invention is measured in the width direction using the JIS B0601 method, the cutoff value is 0.8 mm, and the Ra on the substrate side surface (in the case of the single roll method, the roll surface side) is 0.2 ~ 0.5μ
m, the free surface is 0.1-0.5 μm, and the substrate surface of the amorphous alloy ribbon produced by the conventional single-sided cooling method is 0.6-0.6 μm.
It is clear that it is extremely smooth compared to the free surface of 1.3 μm and 0.6 to 1.5 μm. Since the amorphous alloy ribbon of the present invention is thick and has a smooth surface, it has an extremely high space factor when laminated. 750 g of the amorphous alloy ribbon of the present invention with an average thickness of 60 μm and a width of 25 mm is placed on a bobbin with an outer diameter of 40 mm.
The filling factor was 91% when wound with a tension of Kg. In contrast, the space factor of conventional materials is normally 80 to 85% when the thickness is 30 μm. When a material with a high space factor is used for a magnetic core or the like, it is practically advantageous because it can be miniaturized. The amorphous alloy ribbon of the present invention mainly contains Fe,
It is an alloy containing one or more of B, Si, C, P, etc. as a semimetal, and Fe may be partially replaced with other metals depending on the required characteristics. That is, when magnetic properties are required, up to 1/2 of Fe may be replaced with one or both of Co and Ni. In addition, Mo, Nb, Mn,
One or more types of Sn to improve corrosion resistance
One or more of Mo, Cr, Ti, Zr, V, Hf, Ta, W, Mn, Al,
Cu, Sn, etc. may be added. The content range for Fe is 50 to 82% (at%, same hereinafter) (however, 1/ of Fe
2 or less can be replaced with one or two of Co and Ni),
B is selected from 8 to 17%, Si from 1 to 15%, C from 3% or less, and other elements from a total of 10% or less depending on the use. Also, the total of all elements that make up the alloy is
Set as 100%. When the amorphous alloy ribbon of the present invention is used, for example, as an iron core material, the preferred composition is Fe _a B _b Si _c C _d , and the range of each component is a: 77-82, b: 8-8.
15, c: 4-15, d: 0-3. Next, examples of the present invention will be shown. Example 1 Using a single roll made of Cu, an alloy having the composition shown in Table 1 was cast into an amorphous alloy ribbon having a width of 25 mm. However, the nozzle used has three slot-shaped openings (width d0.4 mm, length l 25 mm, spacing a 1 mm) as shown in Figure 1, and the manufacturing conditions are a jetting pressure of 0.20 to 0.35 kg/
cm ² , a roll circumferential speed of 20 to 28 m/sec, and a nozzle-to-roll distance of 0.15 to 0.25 mm. Table 1 shows the plate thickness, surface roughness, and space factor of the amorphous alloy ribbon of each composition. Furthermore, Table 1 lists typical characteristics of conventional materials produced using the single roll method as comparative examples.
It is clear that the amorphous alloy ribbon of the present invention has a larger thickness, lower surface roughness, and higher space factor than conventional materials. Amorphous alloy ribbon of the present invention (plate thickness 62μ
Examples of the surface roughness profiles of the material (plate thickness: 40 μm) and the comparative material (plate thickness: 40 μm) are shown in FIGS. 2a to 2d. a is the free surface of the amorphous alloy ribbon of the present invention, b is the roll surface of the same as above, c is the free surface of the comparative material, and d is the roll surface of the same as above. Furthermore, the amorphous alloy of the present invention produced by the method of Example 1 has the following characteristics not found in conventional materials. That is, the magnetic domain structure of the as-cast amorphous alloy ribbon of alloy No. 1 in Table 1 is as shown in FIG. 3a.
Compared to the as-cast magnetic domain structure of the conventional material shown in FIG. 3b, the amorphous alloy ribbon of the present invention has a completely different aspect. That is, while the conventional material exhibits a complicated labyrinth-like magnetic domain pattern, the amorphous alloy ribbon of the present invention already consists of 180° magnetic domains aligned in the length direction even after being cast. This shows that the amount and distribution of strain inside the amorphous alloy ribbon are completely different. As suggested by the magnetic domain pattern in FIG. 3a, the amorphous alloy ribbon of the present invention can be used in various magnetic applications, such as the iron core of a high-frequency transformer, even when it is cast. Figures 4a and 4b compare the magnetic domain structures after annealing in a magnetic field. The amorphous alloy ribbon a of the present invention has a magnetic domain width several times larger than that of the conventional material b. This is thought to be due to the smoothness of the surface, which has fewer surface defects that inhibit the movement of domain walls. Example 2 Using the same single roll, nozzle, and manufacturing conditions as in Example 1, an alloy having the composition shown in Table 2 was cast into an amorphous alloy ribbon having a width of 25 mm. Thickness of amorphous alloy ribbon of each composition,
The surface roughness and space factor are shown in Table 2 along with comparative examples. Compared to conventional materials, the amorphous alloy ribbon of the present invention has
It is clear that the plate thickness is large, the surface roughness is small, and the space factor is high. Therefore, it can be used for various purposes. (Effects of the Invention) As explained above, the Fe-based amorphous alloy ribbon of the present invention has a large thickness and a smooth surface. However, there were many problems such as the efficiency of lamination work and the mechanical strength of the core, so it was considered impossible to use it in the stacked core method, so it had to be used in the form of a wound core.
The amorphous alloy ribbon of the present invention can be applied to laminated iron cores, and when laminated, the space factor of the materials can be greatly improved and the core can be made smaller. Furthermore, even when used for purposes other than iron cores, its large thickness provides high mechanical strength, and its smooth surface allows it to be used in a variety of applications, making it highly effective.

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【table】 [Brief explanation of the drawing]

Fig. 1 is a bottom view showing a nozzle for manufacturing the amorphous alloy ribbon of the present invention, and Fig. 2 a to d show the amorphous alloy ribbon of the present invention (a: free surface, b: roll surface) and a comparative material. (c: free surface, d: roll surface) An explanatory diagram showing the surface roughness, Figures 3a and b show the metal magnetic domain structure of the as-cast free surface of the amorphous alloy ribbon of the present invention and the conventional material. The photographs, FIGS. 4a and 4b, are also photographs showing the metal magnetic domain structure of the free surface after annealing.

Claims (1)

[Claims] 1. The plate thickness is more than 50 μm, the plate width is more than 20 mm, and the surface roughness is 0.5 μm on the free surface with respect to the cut-off value of 0.8 mm when measured according to JIS-B0601 method.
The following is a large-thick Fe plate whose roll surface Ra is 0.5 μm or less and which is produced by a single-sided cooling method and by applying pressure while the alloy on the cooling substrate is not solidified.
Base amorphous alloy ribbon. 2. The thick Fe-based amorphous alloy ribbon according to claim 1, which has a thickness of 55 μm or more and a width of 25 mm or more.