Metal treatment – Stock – Magnetic
Patent
1986-06-19
1987-11-17
Sheehan, John P.
Metal treatment
Stock
Magnetic
148306, 148403, 420 84, 420579, 420581, H01F 104
Patent
active
047071982
DESCRIPTION:
BRIEF SUMMARY
1. Technical Field
The present invention is related to a novel amorphous alloy and a production method thereof, more particularly, to an amorphous alloy having a good corrosion resistance and being capable of utilization as an information-recording material, magnetic material, and the like.
2. Background Art
A disordered structure of an alloy, in which the periodicity accompanied by the crystal structure is lost, generates a certain kind of homogenity. This homogenity resides in an absence of grain boundaries, lattice defects and the like present in the crystal structure, and in a composition free of precipitates, segregations, and the like. As a result, the amorphous alloy can realize an alloy having a composition which is homogeneous and varies continuously over a broad composition range. This means that elements which cannot be mixed homogeneously in the crystal structure can provide various alloys in the case of an amorphous structure.
Note, in Japanese Unexamined Patent Publication No. 52-31703, it is disclosed that an amorphous alloy consisting of the general formula Fe (iron)-R (rare earth element), for example, Fe-Tb (terbium), allows the magnetic properties, e.g., Curie point and coercive force, to be varied by means of a continuous change of the Tb composition.
In addition, in Japanese Examined Patent Publication No. 54-15483, it is disclosed that a Te (tellurium)metalloid series-alloy containing, for example, 30 atomic % or more of Te and at least one element selected from the group consisting of In, Sn, Pb, P, As, and S, is used as a recording medium by piercing with laser light.
DISCLOSURE OF THE INVENTION
The Fe-series alloys have many phase-transformations in the crystal structure and noticeable magnetic properties, and therefore, the Fe-series alloys are useful as a number of industrial materials. On the other hand, Te has characteristics in that it is a semiconductor and exhibits an extremely small heat conductivity as compared with ordinary metals. Another characteristic of Te is that it exhibits a strong absorption of laser light having a wavelength in the neighbourhood of 800 nm, which is generally used as a light source for the writing in light recording. The characteristics of Te are conspicuous.
Notwithstanding the characteristics of Fe and Te, industrially useful, available materials in which Fe and Te are combined, are only limited Fe-Te series alloys in the following. In these alloys, Te is not solid-dissolved. They are crystallites. The compositions of these alloys include Fe Te, FeTe.sub.2, and the like, and hence are sporadic. Their structure is crystal or composite-crystal exhibiting segregation and/or precipitation.
The present invention made in-depth studies of ways to provide a solid solution of a composition in which the proportion of Fe to Te continuously varies, and discovered that when the Fe composition exceeds that below which Te intrudes into the lattices of Fe, the Fe-Te alloy is rendered amorphous and a solid solution is obtained in which the Fe and Te composition continuously varies.
Accordingly, a specified invention according to the present invention resides in a novel amorphous alloy having an excellent corrosion resistance and consisting of Fe-Te with a Te content of from 14 to 90 atomic %. The second invention resides in a method of production of the novel amorphous alloy.
The novel alloy according to the present invention is expressed by the general formula Fe.sub.100-x Te.sub.x (herein, x is atomic %) and has an amorphous structure. When Te is successively added to polycrystals of Fe by a trace amount, Te intrudes into the Fe lattices which thus undergo strain.
The following structural changes depending upon the Te content were recognized. That is, when x is less than approximately 7%, an .alpha.-Fe (Te) solid solution is formed. When x exceeds approximately 7%, the structure is transferred to a transitional region, in which an amorphous structure is dispersed in the crystalline structure. In a composition having an x of 12%, the lattice strain is conspi
REFERENCES:
patent: 4282034 (1981-08-01), Smith et al.
patent: 4560454 (1985-12-01), Harris et al.
Chiba Kiyoshi
Ino Hiromitsu
Tokumitsu Kazuto
Sheehan John P.
Teijin Limited
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