JPS5923851A - Alloy with high magnetic permeability - Google Patents

Abstract

PURPOSE:To increase the effective permeability and saturation magnetic flux density of the resulting alloy and to improve the wear resistance by providing a specified composition consisting of Al, Si, Ru, Ti and the balance Fe. CONSTITUTION:This alloy with high magnetic permeability has a composition consisting of, by weight, 3-10% Al, 4-11% Si, 2.1-20.0% Ru, 0.2-5.0% Ti and the balance Fe. The alloy has a higher saturation magnetic flux density than ferrite and superior wear resistance, and defects such as chipping, cracking and stripping are hardly caused when the alloy is worked and assembled.

Description

[Detailed description of the invention]

The present invention has high effective magnetic permeability (Fe), high saturation magnetic flux density (Bs), and excellent wear resistance, and can be used as a magnetic herad core material in particular to obtain strong leakage magnetic flux even in a narrow gap, and can be processed and assembled. This relates to high magnetic permeability alloy C1, which has fewer defects such as chipping, cracking, and peeling.In recent years, with the advancement of magnetic recording technology, the magnetic head gap width has become smaller due to the need to improve recording density. A magnetic head core material with a high saturation magnetic flux density CBS that can obtain strong leakage magnetic flux even with a correspondingly narrow gap has become required. A high magnetic permeability alloy called Sendust, which consists of 10% Si and 85% Fe (hereinafter referred to as wt %), has attracted attention.This alloy has excellent magnetic properties, and has a particularly high saturation magnetic flux density (B However, the wear resistance was insufficient as a magnetic herad core.Therefore, sendust alloys with improved wear resistance by adding small amounts of special metals were put into practical use and are rapidly becoming popular. However, the wear resistance of ferrite is still not as good as that of ferrite c, so it cannot be said to be sufficient.
It is extremely low at about t8゛. However, recently, in order to further improve recording density, magnetic tapes and magnetic cards that use ultrafine metal powder with high coercive force as recording media instead of conventional metal oxides have been put into practical use. A high magnetic permeability alloy with a magnetic herad core (high saturation magnetic flux density CBS) is desired (2).In addition, since Sendust has insufficient wear resistance as a magnetic herad core, it is necessary to use special elements. Although trace amounts of several types of elements are added, the addition of these special elements is harmful to the effective magnetic permeability (μe) and saturation magnetic flux density of Sendust, and the saturation of Sendust alloys that impart wear resistance. Magnetic flux density (Bs)
A decrease in the magnetic flux density was inevitable, and as a result it was extremely difficult to obtain a magnetic herad core material with a high saturation magnetic flux density. Additionally, Sendust alloys that have been given wear resistance in this way have the disadvantage of being prone to defects such as two chips, one cracks, and peeling during processing and assembly.On the other hand, ferrite is known as a magnetic head core abrasion. Its effective magnetic permeability is the same as that of Sendust, and its wear resistance is the best among the currently used magnetic head core materials, but its saturation magnetic flux density is low.
It is about 000. Permalloy, which is the most commonly used magnetic herad core material, exhibits performance similar to Sendust alloy in both effective permeability and saturation magnetic flux density IW, but wear resistance is ↑
Housing is extremely low. The present invention was made in view of this (1), and obtained a high magnetic permeability alloy with a saturation magnetic flux density equal to or higher than that of ferrite and a wear resistance superior to that of ferrite.
10%, Si4-11%, Ru2.1-20%. It is characterized by consisting of Tio, 2 to 5.0% balance pe. That is, as a result of various studies in order to obtain a material with better wear resistance than ferrite and a saturation magnetic flux density higher than that of ferrite, the present inventors found that Si 4-11%, A13-10%,
Adding 21 to 20.0% of P'e-8i-AI ternary alloy (2. However, if Ru is added in a small amount, the opposite is true (I know of an actual vehicle that improves these magnetic properties and overturns the conventional wisdom that the increase in coercive force is small. Also, adding 21% or more of Ru improves magnetic properties. The present inventors discovered that the abrasion resistance with recording media such as tapes and magnetic cards was dramatically improved, and furthermore, the present inventors discovered that R
Adding Ti to Fe-8i-A, l-based alloy containing u from 02 to
Adding 5.0% significantly strengthens the grain boundaries of the alloy,
As a result, it was discovered that defects such as chipping, cracking, and peeling during processing such as grinding, cutting and polishing, and during head assembly were largely suppressed, resulting in a high saturation magnetic flux density (Bs) and an excellent We have developed a high magnetic permeability alloy with high wear resistance. The reason why the composition of the alloy of the present invention is limited as described above is as follows. That is, the AI content is 3 to 10%, and the Si content is 4 to 11%.
The reason for this is that even if either AI or Si is below the lower limit or exceeds the northern limit, the magnetic properties, especially the effective magnetic permeability, will drop significantly, making it impossible to use it for magnetic head cores, etc. Moreover, the reason why the Ru content is set to 2.1 to 20.0% is that if the Ru content is less than 2.1%, the saturation magnetic flux density (13
s) and wear resistance are not significant.-R
If the N content exceeds 20.0%, harmful phases will crystallize, resulting in a sharp decrease in saturation magnetic flux density () 3 s) - effective magnetic permeability (μ) and wear resistance. 3
Toyoi is added in a range of 0% or more and 15.0% or more. Furthermore, the reason why the Ti content was set to 0.2 to 5.0% was that 'l+
If the i content is less than 0.2%, grain boundary strengthening will be insufficient and defects such as chipping, cracking, and peeling during processing and assembly cannot be suppressed, and if it exceeds 5.0%, the overall magnetic properties will deteriorate. This is because it reduces its suitability as a magnetic rad core material, and it is preferably added in a range of 0.7% or more and 40% or less. In this way, the effect due to the addition of Ru in the present invention is a completely unusual and unique phenomenon, and it is generally the case that the effect due to the addition of Ru in the Sendust system (in most cases other than Fe, AI, and Si) is the addition of a fourth element. not only lowers the saturation magnetic flux density If (138) but also causes a sharply low effective magnetic permeability (μe) and a significant increase in coercive force (H).
Addition of fa elements improves the hardness and wear resistance of the alloy, but almost without exception it impairs the magnetic properties of the sendust alloy. In contrast to this (2), the addition of Ru of the present invention has an unusual effect of improving the effective magnetic permeability (μ) within the range that is the opposite. It has a high saturation magnetic flux density (1-30) that breaks the limits of ferrite, which is a material for RAD cores, and has excellent wear resistance of 1'-1, and can greatly contribute to the development of magnetic recording technology. The alloy of the present invention will be explained using two examples.
Blend 9.9% Ti at a ratio of 4Φ/J (7) and melt this in a high frequency vacuum melting furnace (vacuum level 3) using an aluminum crucible.
~7X10-3mHg+2 and cast in two cast iron molds C2, having the composition shown in Table 1, thickness 25 mm, width 25 mm.
WIA, an ingot with a length of 160** was obtained. These are subjected to eccentric processing, wire cutting, wrapping ≦2, outer diameter 8 in order, inner diameter 4
Fin, 2fi thick ring for measuring magnetic properties and thickness Q6+x
A test piece for measurement of abrasion resistance and 4 holes was prepared with a medium size of 3.211 m and a length of 85 pieces. These (two are τ, ゛(100 in the air)
After heat treatment at 0° C. for 1 hour, magnetic properties and 1V resistance were measured. The results are shown in Table 1. Ring for measuring magnetic properties (two of them are B-H) laser (two-up [3-Hllll line) was planted, and from this, the saturation magnetic flux density (13S) and coercive force (11) were determined, and a vector interference meter ( The effective magnetic permeability (zle) at IKHzl2 was measured from 2. Also, if wear resistance ≦ 2, after measuring the hardness of the test piece (2 micro Vickers), as shown in Figure 1 C2 (- test piece 7 sheets of +11 stacked together with a thickness of 1.
They are placed facing each other with a 2 μm Ti foil (2) interposed therebetween, and are arranged with a radius of 1
The curved surface of the mackerel (4) was inserted into a brass fixing frame (3) with a rectangular hole (5) with a width of 6.4 fl and a height of 4.2 fins (5), fixed with resin, and the curved surface ( 4) was polished with GC2000 to create a dummy head for wear resistance testing, which was placed on a cassette deck and placed in an atmosphere at a temperature of 30°C and humidity of 75%.

[1] The wear resistance was measured by sliding it on a magnetic tape for 300 hours. Also, from the above ingot, the width is 20 mm, the Asahi width is 20 mm, and the length is 100 mm.
A 1N square bar was prepared, its side surface was polished with a GC grindstone, and the number of chips that occurred at the edge of the polished surface and the number of flakes that occurred within a 1cIn square area selected due to neglect of the polished surface were measured. , the total number is shown in Table 1 (both of them are shown in Table 1). It can be seen that the occurrence of defects such as chipping, cracking, and peeling is significantly reduced.Special C2 Invention Alloys 1 to 13 and Conventional Alloy/l617./1618
．． As can be seen by comparing /l620 and Flat 21, the Ru content is 3.0 to 5.0% and the Lrl content is 0.3 to 3.0.
% range, the effective magnetic permeability, saturation magnetic flux density, and wear resistance are significantly superior, and the number of defects is extremely low. On the other hand, when comparing conventional alloy scrap] 7 and 421-A22, it is clear that both the one to which Yuharu's TI was added and the one to which small amounts of Tt and Zr were added had poor wear resistance and defect generation. Although improved, the effective magnetic permeability and saturation magnetic flux density have decreased. As described above, the alloy of the present invention has a saturation magnetic flux density If higher than that of ferrite and excellent wear resistance, and also suppresses the occurrence of defects during processing and assembly, and can be used as a magnetic herad core to generate strong leakage magnetic flux even in a narrow gap. It has remarkable industrial effects, such as the ability to

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a dummy head for wear resistance testing. 1. Test piece 2. Ti foil 3. Brass fixed frame 4,
Curved surface 5 square holes Figure 1

Claims (1)

[Claims] AI3~10W1%, Si4~11wt%, Ru
2.1-20. Owt%, Ti002~5. Qwt%,
High magnetic permeability alloy with high saturation magnetic flux density and excellent wear resistance, with the remainder being Fe.