JPS6238424B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an amorphous magnetic alloy with excellent wear resistance and corrosion resistance. In recent years, advances in ultra-quenching technology have made it possible to obtain various amorphous magnetic alloys. These are mainly obtained by the combination of metal elements and semimetallic semiconductor elements, and the typical ones are Fe-P-C, Fe-B-
C, Co-Si-B, Fe-Co-B, Fe-Ni-P-
B, Fe-Si-B, etc. Since these amorphous alloys have excellent soft magnetic properties and high hardness, studies on stress on the magnetic head core are progressing. However, although the wear resistance of the head is sufficiently superior to Permalloy, it is not superior to Sendust, and has the disadvantage of being inferior to Permalloy and Sendust in terms of corrosion resistance. Corrosion resistance has been improved by adding about 7% Cr, but
This is not a very desirable improvement method because it involves a significant decrease in saturation magnetic flux density. Among the amorphous alloys obtained by combining the above-mentioned transition metals and metalloids, the one that can achieve the highest saturation magnetic flux density B _s is an alloy that uses only B or B and C as metalloids.
This system was extremely difficult to manufacture. By adding Nb to this system, the present inventors not only made it extremely easy to make it amorphous, but also achieved the effect of Nb, which made it possible to make it amorphous even in areas where there was very little B, which was previously impossible. , conventional B,Si-B,P-
Compared to amorphous alloys of B, B-C, and P-C systems, Nb
- Discovered that B-series alloys have excellent wear resistance (Japanese Patent Application No. 164978-1982). The present inventors further conducted research and found that among these systems, in particular, metalloids such as B are contained in an amount of 10% or less,
Contains 6% or more of Nb. () M _a Nb _b X _c (M = one or two of Fe, Co, Ni, Mn, Cr, Mo, W; The various properties of samples having the following composition range (71a94 6b<20 0c<10) were investigated. As an example, correlation data between the amount of B and wear resistance is shown in FIG. Wear measurement was performed by attaching a laminated amorphous alloy with a track width of 200 μm and a width of 2 mm as a dummy head to the VTR deck, running the CrO _z tape at a relative speed of 5.6 m/sec with the dummy head for 20 hours, and measuring the amount of wear on the head. He did this by doing. It can be seen from FIG. 1 that extremely excellent wear resistance is exhibited when the amount of B is 10% or less. To make amorphous in a region containing less than 10% metalloid
6% or more of Nb is required, and in this region, Nb mainly acts as an element that enables amorphization.
It has been found from the experimental results that B, C, Si, Ge, Al, and Sn play a supporting role to make the amorphization even easier. Therefore, it is thought that an amorphous alloy with a metal-metal bond has better wear resistance than an amorphous alloy with a metal-metalloid bond. Table 1 shows the results of measuring the amount of wear after 1000 hours by attaching various amorphous alloy dummy heads to an audio cassette tape recorder and running a _CrOz tape at a speed of 4.75 cm/sec. Shown in Table 1. Contains no metalloids according to the data shown in the same table.
It was found that sample No. 2, as well as samples No. 9 and 10 containing only a small amount of metalloid, had better wear resistance than samples containing a large amount of other metalloids, and sample No. 11, which did not contain Nb, had extremely poor wear resistance. . From the above, () does not include X. It has been found that an amorphous alloy having a composition of ( )' MaNb _b , 80a≦94, 6≦b≦20 (atomic %) is practically desirable.

[Table] The present inventors also discovered that an amorphous alloy containing 6% or more of Nb also has excellent corrosion resistance. Experimental results revealed that this is because Nb forms a passive film. Figure 2 shows the potentiodynamic polarization curve of the alloy of the present invention.
Curves). This shows that the amorphous alloy containing Nb forms a passive film. Also, if more than 10% of metalloids such as B are added, even if Nb is 6
% or more, the stability of the passive film deteriorates. Furthermore, if Nb is added in an amount of 20% or more, the saturation magnetic flux density B _s is significantly reduced, so it is practically desirable that b<20. Next, the present inventor discovered that an amorphous alloy with excellent properties could be obtained by using a specific metal T=Ti, Zr, Hf, V, Ta in place of the above-mentioned X. Unlike X mentioned above, these metals did not cause any deterioration in wear resistance even when added in an amount of 10% or more; Since these materials significantly deteriorate the corrosion resistance, it is preferable to keep the content within 5% in order to maintain the advantages of a magnetic alloy. Figure 3 shows how the saturation magnetic flux _density B _s changes when various types of T are added to Co _{85.5 Nb 14.5} . Furthermore, in order not to damage Nb too much, B _s
It is desirable that the concentration be 20% or less, and 6% or more is required to make it amorphous, so in this system, () MaNb _b T _d (T=Ti, Zr, Hf, V, Ta ) However, a composition range of 76a94, 6b20, 0.1d<5 is practically desirable. Amorphous alloys within the composition range shown in ()' are shown in Table 2, showing good wear resistance and corrosion resistance similar to those shown in ()' above, as shown in Table 1. The results of the wear resistance test are shown.

[Table] Next, the present inventors added Y and rare earth elements to Co-
The effect of adding Nb to an amorphous alloy whose main component is Nb was investigated. However, in the ultra-quenching method using the conventional one-roll method, the addition of rare earth elements does not show much effect on forming an amorphous ribbon, and in fact 2%
The above addition resulted in hindering formation of an amorphous ribbon. However, when an amorphous thin film was created using a sputtering method and a vapor deposition method, it was found that the addition of small amounts of Y and rare earth elements significantly increased the crystallization temperature and exhibited a very favorable effect. However, 5
It was also found that addition of more than % of the amorphous Co--Nb film causes a rapid increase in Hc that significantly impairs the soft magnetic properties of the amorphous Co--Nb film, resulting in unfavorable results. Therefore, the practically desirable composition range is 6 for the same reason as mentioned above.
Considering the conditions for b20, it is as follows. () M _a Nb _b R _f a+b+f=100, 70a94, 6b20,
0.1f<5 Table _{3 shows} how the crystallization temperature Tx changes when Y and various rare earth elements are added _{to Co85.5Nb14.5} .

[Table] Also, Figure 4 shows the results when various rare earth elements are added.
The change in Hc is shown. As mentioned above, adding a small amount of rare earth elements is extremely effective when creating a Co--Nb amorphous thin film by sputtering or vapor deposition. In addition, since it is generally easier to make amorphous by sputtering method or vapor deposition method than by ultra-quenching method, (),
It goes without saying that an amorphous thin film can be created more easily by combining the composition ranges mentioned in () and () with this rare earth element, and their desirable composition range is () M′ _a Nb _b T _d R _f 71≦a<94, 6b<20, 0.1d<5, 0.1
f<5. An amorphous alloy thin film with these compositions was deposited on a Mn-Zn ferrite substrate to a thickness of 20 mm using a sputtering method.
The crystallization temperature T _x and wear test results of typical compositions are shown in Table 4. The amount of uneven wear was determined by the V.
The TR deck was run for 100 hours, and the amount of depression in the amorphous area was measured compared to the ferrite surface. FIG. 5 illustrates the experimental method.

[Table] In Fig. 5, Fig. 5a shows the tip of a dummy head chip of a VTR, with the left side showing a front view and the right side showing a side view. In the figure, 1 and 2 are ferrite parts, 3 is an amorphous sputtered film, and 4 is a tape sliding surface. FIG. 5b shows the state of wear of the dummy head chip, and Δl indicates the amount of uneven wear. As can be seen from the experimental results in Table 4, the amorphous alloy of the present invention has a high crystallization temperature and excellent wear resistance, making it a material that can be used for head cores for VTRs. Furthermore, since Nb forms a passive film in the amorphous alloy of the present invention, it also has excellent corrosion resistance. Furthermore, when an amorphous film is formed by sputtering or vapor deposition, the addition of rare earth elements has the effect of increasing the crystallization temperature of the resulting alloy. As described above, the magnetic metal element of the present invention and Nb
In addition to having high saturation magnetic flux density and soft magnetic properties, the amorphous alloy whose main component is
This alloy has corrosion resistance and is ideal for core material for magnetic heads.

[Brief explanation of the drawing]

Figure 1 shows the wear resistance properties of amorphous alloys and the B contained in them.
Figure 2 shows the correlation characteristics with the amount of (Co. ₈₅₅ Nb.
₁₄₅ ) _100-x B _x (X=2, 5, 10, 12) and
Figure 3 shows the corrosion voltage-current curve of Co ₇₅ Si ₁₀ B ₁₅ in a 1 mol NaCl solution. Figure 3 shows an amorphous alloy (Co. ₈₅₅ Nb.
₁₄₅ ) Diagram showing the change in saturation magnetic flux density B _s of _100-x T _x ,
FIG. 4 is a diagram showing changes in Hc of (Co. ₈₅₅ Nb. ₁₄₅ ) _100-x R _x , and FIG. 5 is a diagram showing a method for measuring uneven wear of a sputtered film. 1, 2... Ferrite, 3... Amorphous sputter film, 4... Tape sliding surface.

Claims (1)

[Claims] 1. essentially 80 to 94 atomic % of a metal element M;
An amorphous magnetic alloy characterized by comprising 6 to 20 atomic percent Nb. However, M is one or more metal elements selected from the group consisting of Fe, Co, Ni, Mn, Cr, Mo, and W. 2 essentially 76 to 94 atomic % of the metallic element M;
An amorphous magnetic alloy comprising 6 to 20 atomic percent Nb and 0.1 to less than 5 atomic percent metallic element T. However, M is one or more metal elements selected from the group consisting of Fe, Co, Ni, Mn, Cr, Mo, and W, and T is selected from the group consisting of Ti, Zr, Hf, V, and Ta. One or more metal elements. 3 essentially 76 to 94 atomic % of the metallic element M;
6 to 20 atomic% Nb, Y and rare earth elements 0.1
An amorphous magnetic alloy characterized in that it consists of from 5 at. However, M is one or more metal elements selected from the group consisting of Fe, Co, Ni, Mn, Cr, Mo, and W. 4 essentially 71 to 94 atomic % of the metallic element M;
1. An amorphous magnetic alloy comprising 6 to 20 atomic % of Nb, 0.1 to less than 5 atomic % of metallic element T, and 0.5 to less than 5 atomic % of Y and a rare earth element. However, M is one or more metal elements selected from the group consisting of Fe, Co, Ni, Mn, Cr, Mo, and W, and T is selected from the group consisting of Ti, Zr, Hf, V, and Ta. One or more metal elements.