JPS59170234A - Magnetic alloy - Google Patents

Abstract

PURPOSE:To obtain a magnetic alloy having superior corrosion resistance, wear resistance and hot workability and suitable for use as the material of a magnetic shield member by adding small amounts of Mg, Si and Zr to an Ni-Fe-Cu alloy having a specified composition. CONSTITUTION:0.001-0.02% Mg, 0.01-3% Si and 0.05-1.0% Zr are added to an Ni-Fe-Cu alloy contg. 57-74% Ni and 12-32% Cu. A magnetic alloy having magnetic characteristics suitable for a shield case for the magnetic head of a magnetic recording device as well as superior corrosion resistance, wear resistance and hot workability can be manufactured without using expensive Mo while reducing the amount of Ni used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic alloy that has good magnetic properties when applied to materials and has improved hot workability without losing the magnetic properties.

A magnetic/hard part using a Ni--Fe based high magnetic permeability alloy is widely used as a 7-hard case for a magnetic henode in a magnetic recording device such as a cheap recorder. Among these, high-N1 alloys (OS-PC materials) and low-Ni alloys (JIS-PB materials) containing Mo, Cu, etc. are often used. The former has high magnetic permeability and crystal corrosion resistance, but uses expensive Nl.

Contains a large amount of 76% by weight or more (hereinafter simply referred to as "related"),
Furthermore, since it also contains expensive MO, it has the disadvantage of being expensive among magnetic alloys. In addition, since the latter has an NX amount of about 45%, it is inexpensive and the magnetic flux density B10 at 10 oerste is 1 40 00 Gau.
ss, but on the other hand, the monophagous property is extremely poor and the initial permeability μ
The disadvantage is that m is 5000, which is lower than the former. For example, in order to use an inexpensive 15% Ni--Fe permalloy as a head case for a magnetic shield, it is necessary to perform a plating treatment to prevent rust, which is industrially disadvantageous.

Therefore, with conventional JIS-PC and PB materials, it is difficult to obtain a magnetic alloy material that has excellent magnetic properties, high corrosion resistance, strength, and low cost. however.

Industrially, there is a strong demand for cheaper magnetic alloys that have poor magnetic properties, hot workability, and corrosion resistance.

The present invention has been made in response to the above demand.

JIS-PC material without sacrificing its properties.
The present invention provides a new magnetic alloy that does not contain any Ni and has a reduced content of Ni, which is more expensive.
Research on alloys has been ongoing for a long time, and it is well known that they have excellent magnetic properties (for example, R-
Ferromagnetis by M. Bozorth
m I', D, vanNostrand Co-]
951), Ni amount is 74-8Q%, Cu amount is 1
Those with a content of 0% or less are in practical use. However, C
If the amount of u exceeds 10, it is difficult to control the composition due to the segregation of Cu during casting, and furthermore, there is a drawback that hot workability is significantly deteriorated, making it difficult to put it into practical use.

The present inventor has already filed a patent application in 1983. In No. 1.97617, as one of the co-inventors, I added small amounts of Mg, 3i and Mn to an alloy consisting of 57-74% Ni + 12-32% Cu, the balance being Fe. ,
In particular, by adding 0.02% to 0.02% Mg, hot workability is significantly improved, and the magnetic properties are on the same level as JIS-PC materials, and the segregation of Cu that occurs during casting is reduced. It was revealed that the variation in the amount of Cu within the ingot can be suppressed to within ±005 degrees by adjusting the cooling rate during casting.

In addition, one of the present inventors, together with the same co-inventor, proposed in Japanese Patent Application No. 56-200045 that Ni 57-74% by weight,
A part of the Fe of the alloy consisting of Cu 12-32, 0.3-3.0% Si and 0.001-0
．． It was revealed that by replacing it with 0.2% Mg, the magnetic permeability was improved by several orders of magnitude compared to the ternary alloy, and the hot workability and corrosion resistance were improved.

However, when these alloys are used as shield cases for magnetic fields, their wear resistance is not necessarily sufficient. As a result of repeated experiments to improve wear resistance, it was discovered that adding a small amount of Zr contributes to improving wear resistance and also improves corrosion resistance.

The present invention has been made based on the above considerations. That is, the alloy of the present invention contains 57 to 74% Ni and Cu
12-32%, SiO, 01-3%, Zr0.05-1
%, Mg 0.001-0.02% and the balance is F
It is characterized by consisting of e.

Here, Ni has a high magnetic permeability in the range of 57 to 74 modulus, but if the Ni content is less than 57%, the magnetic permeability decreases and the corrosion resistance is significantly inferior, and when it increases to 74%, the amount of Cu added is 12 modulus or more. The magnetic permeability decreases significantly.

Further, those with N1 exceeding 74% are industrially disadvantageous when resource saving and price reduction are taken into consideration.

Cu has high magnetic permeability within the range of 12-32%, but C
When u is less than 12%, high magnetic permeability cannot be obtained unless the Ni content exceeds 74 modulus, and when Cu exceeds 32%, the initial permeability is μm.
and the hot workability also deteriorates.

Si is added to improve the corrosion resistance of the alloy and to reduce magnetostriction and magnetic anisotropy. Si
By adding , a thin Si oxide coating is formed on the alloy surface layer during magnetic annealing, and this acts as a passive coating to improve corrosion resistance. In order to form a Si oxide film, it is necessary to add 0.3% or more of Sl.
If it is less than 0.03%, no oxide film will be formed and corrosion resistance will deteriorate. Even if Si is added in excess of 30%, an oxide coating will be formed and the tetragonal properties will be improved, but at the same time the magnetic flux density B1 will increase.
Magnetostriction and magnetic anisotropy increase as o decreases significantly. From the above, the amount of Si added is 0.3 to 3.
The range of coefficient 0 is suitable for increasing corrosion resistance and further reducing magnetostriction and magnetic anisotropy. Si is 0.01~03
%, 31 mainly acts as a deoxidizing agent and cannot improve the corrosion resistance, but the effect of +Zr makes the corrosion resistance sufficiently satisfactory. Therefore, 81 may be in the range of 0.01 to 3%.

Zr is added to improve wear resistance and corrosion resistance. If it is less than 0.05%, the effect is not obvious and 1
If the temperature exceeds this limit, wear resistance and corrosion resistance will further improve, but hot workability will deteriorate significantly.

Mg is added to improve hot workability and is 0.
If it is less than 0.001%, no effect will be obtained, and if it exceeds 0.002%, the initial magnetic permeability will decrease and it will not be practical.

Note that the alloy of the present invention contains a deoxidizing agent and At as a desulfurizing agent.

C+Ca+Mn, etc. may be added in a total amount of one or less.

Next, an example will be described.

<Example> After melting to the composition shown in Table 1, the ingot was poured into a mold and the ingot was heated at an appropriate cooling rate to prevent segregation of Cu. Plate materials with a thickness of 0.5 mm were produced by hot working and cold working.No knot cracks, edge cracks, etc. occurred during hot working, and the hot workability was good. A ring for measuring magnetic properties (outer diameter 45 mmφ, inner diameter 33 mmφ), a sample for corrosion resistance test (50 mm x 50 mm), and a magnetic head case for audio for wear resistance test were prepared, and these samples were subjected to magnetic annealing. After.

0 Corrosion resistance: Salt spray test (JIS Z 2371.) 0
Severe abrasion resistance: Wear depth after continuous running for 6+oo hours using an auto-reverse type cassette and deck (teeth 0 speed/1.75 ctn/sec) using γ-Fe203 magnetic tee 70. These results are shown in Table J.

The following can be seen from Table 1.

5) Addition of Si improves surface corrosion and wear resistance, but Zr has a greater effect when added in small amounts (Si
(about 10%) can sufficiently improve corrosion resistance and wear resistance. (
Bian 1, 5, 11. , 12) - As stated (N
By adding S i + Z r )Mg to the i-Fe-Cu alloy, it is possible to obtain a magnetic alloy with excellent corrosion resistance and wear resistance and good hot workability.

This alloy is therefore suitable for use, for example, in magnetic head/rut cases in magnetic recording devices.

Claims (1)

[Claims] 1.Ni57-74%, Cu12-32% in weight%,
Mg 0.001-0.02%, sio, 01-3
%+Zr005~], a magnetic alloy consisting of % and the balance Fe.