JP3735420B2 - Co-based metallic glass alloy - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a Co-based metallic glass alloy, and more particularly, a Co-based metallic glass alloy obtained as a bulk alloy having a much larger thickness than a conventional amorphous alloy ribbon and the like and having excellent magnetic properties. About.
[0002]
[Prior art]
Conventionally, certain types of multi-element alloys have a wide temperature range that is in a supercooled liquid state prior to crystallization, and these are known to constitute metallic glass alloys. This metallic glass alloy is also known to be a much thicker bulk alloy (a lump that is not a specific shape such as wire, grain, ribbon, ribbon, film, etc.) than the conventionally known amorphous alloy ribbon. Yes.
[0003]
For example, as such a metallic glass alloy, Ln-Al-TM (Ln represents a lanthanide metal, TM represents a transition metal), Mg-Ln-TM, Zr-Al-TM, Hf-Al-TM, Ti-Zr- A composition of Be-TM type or the like is known.
[0004]
[Problems to be solved by the invention]
Other alloys having various compositions other than those described above exhibit a supercooled liquid state, but the temperature interval ΔTx of these supercooled liquids, that is, the difference between the crystallization start temperature (Tx) and the glass transition temperature (Tg) ( Considering that Tx−Tg) is remarkably small and therefore practically has poor ability to form metal glass and lacks practicality, it has a wide temperature range of a supercooled liquid like the aforementioned metal glass alloy, The existence of an alloy capable of constituting a metallic glass overcomes the limitation of the thickness of a conventionally known amorphous alloy as a ribbon, and has attracted much attention from the metallurgical viewpoint.
[0005]
However, none of the metal glass alloys known so far has magnetism at room temperature (room temperature), and there are significant restrictions and limitations on practical and industrial utility values in this respect.
[0006]
Accordingly, an object of the present invention is to provide a Co-based metallic glass alloy that overcomes the morphological limitations of conventional metallic glass alloys, can be produced as a bulk material, and can be used as a magnetic material.
[0007]
[Means for Solving the Problems]
This invention makes it possible to produce a bulk glass alloy that has not been known so far, and also provides a metallic glass alloy having excellent magnetic properties at room temperature.
[0008]
The metallic glass alloy of the present invention developed to achieve the above object is related to the temperature interval ΔTx of the supercooled liquid represented by the following formula: ΔTx = Tx−Tg (Tx is the crystallization start temperature, Tg is the glass transition temperature) shows the temperature) Ri is Do the 40K or more Co-based alloy, its composition (atomic percent), Al = 1~10%, Ga = 0.5~4%, P = 10~17%, C = 0. 5 to 7%, B = 2 to 10%, Cr = 7% or less, the balance being Co and 0% or more of inevitable impurities.
[0010]
Any of the Co-based alloys in which glass transition has been observed in the past has a very small temperature interval ΔTx of the supercooled liquid of 25 K or less, and cannot be actually configured as a metallic glass alloy. On the other hand, the present invention is completely unexpected from conventional Co alloys because it has a very wide temperature range where the temperature interval ΔTx of the supercooled liquid is 40K or more. Moreover, the alloy of the present invention, which is also excellent in magnetic properties, is far more practical and industrially superior to the conventional amorphous alloy which is practical only as a ribbon.
[0013]
In the Co-based metallic glass alloy according to the present invention, the temperature interval ΔTx of the supercooled liquid is 40K or more.
In order to produce the above-described metallic glass alloy of the present invention, it is melted and cast, or a liquid quenching method such as a single roll method or a twin roll method, or a submerged spinning method, a solution extraction method, a high pressure gas injection method, etc. Thus, it can be produced in the form of a bulk-like body, a ribbon-like body, a linear body, a powder or the like. And in such a manufacturing method, compared with the case of a conventionally well-known amorphous alloy, a bulky metallic glass alloy which has a thickness and a diameter 5 times or more can be obtained, for example.
[0014]
In addition to the above manufacturing method, a suitable cooling rate is determined depending on the composition of the alloy, the type of manufacturing method, the size and shape of the product, and the range of about 1 to 10 ² K / sec is generally used as a guide. be able to. In practice, the cooling rate and the like can be determined by checking whether or not a phase such as Co ₂ P, Co ₄ B, or Co ₃ B as a crystal phase is precipitated in the glass phase.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
[Example 1]
Co, Cr, Al, and Ga metals and Fe—C alloy, Fe—P alloy, and Fe—B alloy are used as raw materials, and these raw materials are inductively dissolved in an Ar atmosphere, and the atomic composition ratio is Co ₇₀ Cr ₃ Al. An alloy mass of ₅ Ga ₂ P ₁₅ C ₁ B ₄ was produced. Using this alloy, a ribbon having a cross-sectional area of 0.02 × 1.5 mm was produced in an Ar atmosphere by a single roll method.
[0016]
As a result of confirming the ribbon with X-ray diffraction and TEM (Transmission Electron Microscope), it was confirmed that the ribbon was in a metallic glass state. Further, glass transition and crystallization were evaluated by DSC (Differential Scanning Calorimeter). As a result, the temperature interval (ΔTx) of the supercooled liquid represented by the difference (Tx−Tg) between the glass transition temperature (Tg) and the crystallization start temperature (Tx) was 51K.
[0017]
The magnetic properties at room temperature (Bs; saturation magnetic flux density, Hc: coercive force, μe; effective permeability) of the above alloy were evaluated by experiments. Bs = 0.3T, Hc = 4.5 A / m, μe = 5800 An excellent value (f = 1 kHz) was shown.
[Example 2]
In the same manner as in Example 1, an alloy having an atomic composition ratio of Co ₇₀ Cr ₃ Al ₅ Ga ₂ P ₁₅ C ₁ B ₄ was melted. Using this alloy, injection molding was performed using a Cu mold to produce a rod-shaped alloy sample having a circular cross section. The length of the sample was about 50 mm, the diameter was 0.5 mm, and the molding pressure was 0.05 MPa.
[0018]
When the appearance of the sample was observed, it had a smooth surface, good metallic luster, and good moldability. Next, after etching for 10 seconds at 293 K with a solution of 0.5% hydrofluoric acid and 99.5% distilled water, the cross section was observed with an optical microscope. It turns out that it consists only of.
Moreover, a broad peak was also observed as a result of X-ray diffraction, and it was confirmed that the glass phase was a single phase. The magnetic characteristics were the same values as in Example 1.
[0019]
【The invention's effect】
As described above in detail, according to the present invention, limitations such as the thickness of the conventional amorphous alloy ribbon can be overcome, and it can be manufactured as a bulk material and can be applied as a magnetic material having excellent magnetic properties. A Co-based metallic glass alloy can be provided.

Claims (2)

ΔTx = Tx-Tg (Tx crystallization initiation temperature, Tg represents the glass transition temperature) is 40K; Ri Do from (K absolute temperature) or more Co-based alloy, the composition (atomic percent), Al =. 1 to 10%, Ga = 0.5-4%, P = 10-17%, C = 0.5-7%, B = 2-10%, Cr = 7% or less, balance is Co and 0% or more inevitable Co-based metallic glass alloy characterized in that it is a general impurity . _2. The Co-based metallic glass alloy according to claim 1, wherein an atomic composition ratio of the Co-based alloy is Co ₇₀ Cr ₃ Al ₅ Ga ₂ P ₁₅ C ₁ B ₄ .