Other

Tohoku University

Research Development Corporation of Japan

Noboru Tsuya

Kenichi Arai

Toshiro Takahashi

Tadao Tokushima

Tsuyoshi Masumoto

Hiroshi Shimizu

Toshio Takeuchi

The first invention provides a substrate for a magnetic recording medium, which is prepared by forming a macro-concavo-convex pattern for improving CSS properties and a micro-concavo-convex pattern for improving magnetic properties on the surface, thereby preventing the degradation of the CSS properties brought by the enhancement in friction coefficient and the increase in the area of a protective layer of the medium in contact with a magnetic head, caused by the wearing of the protective layer of the medium. The second invention provides a process of producing a substrate for a magnetic recording medium, which forms the above macro-concavo-convex pattern and micro-concavo-convex pattern in a uniform distribution at the same time. The first invention utilizes, as the texture, protrusions 13P and 15P different in length from the substrate surface, the protrusions being prepared by packing at least two kinds of materials 13 and 15 differing in etching rate into alumite pores 14A and 14B, polishing and then etching. The second process invention comprises the steps of packing the first material into alumite pores of an aluminum alloy by means of electrolytic deposition, packing the second material having an etching rate different from that of the first material by means of dipping method, polishing the resultant surface and etching the polished surface so as to make the respective protrusion lengths of the first and the second materials within the predetermined range.

Substrate for magnetic recording medium and process of producing the same

This invention relates to a process for preparing a magnetic disk, which comprises (a) subjecting a substrate having an anodized aluminum film to mirror surface-finishing, (b) widening pores of the anodized aluminum film by chemical dissolution treatment so that the total area of pores becomes from 20 to 80% of the entire surface area, thereby retaining crystalline alumina of the anodized aluminum film extruded after the chemical dissolution treatment, and (c) coating the resultant substrate with a magnetic continuous thin film.

Process for preparing magnetic disk

A substrate for a magnetic disk, having fine roughness formed on its surface by subjecting aluminum or an aluminum alloy to anodic oxidation, packing pores in the anodized layer thereby formed, with a material different in the physicochemical properties from the anodized layer, and letting a plating material grow selectively by an epitaxial method.

Substrate for a magnetic disk and process for its production

A substrate for a magnetic recording disk, made of anodized aluminum having its pores packed with a non magnetic material and having been subjected to polishing followed by an etching treatment to form a finely roughened surface due to preferential etching of either the aluminum or the non magnetic material.

Annodized aluminum substrate for a magnetic recording disk in which

A substrate for a magnetic disk, having an anodized aluminum coating layer with pores widened by chemical dissolution so that the total area of pores is from 20 to 80% of the entire surface area.

A novel thin ribbon of semiconductor has a polycrystalline structure composed more than 50% of grains having a grain size of more than 5 .mu.m, a thickness of 5 to 200 .mu.m, a sufficient flexibility to be windable on a pipe having a diameter of 34 mm, and malleability. The semiconductor is composed of p-type, i-type or n-type semiconductor material, and may be a two-layer composite formed of at least two elements so as to form a p-n type junction. The composition of the semiconductor material consists of pure silicon or silicon with an additional impurity element for improving the properties of the semiconductor, the additional impurity element being selected from the group consisting of hydrogen, phosphorus, sulfur, oxygen, boron, arsenic, tellurium, tin, selenium, aluminum, gallium, indium, chromium, silver, iron and bismuth. A method of manufacturing a thin ribbon of a two-layer composite of semiconductor material is also disclosed. The flexible thin ribbon of semiconductor is available for use as/or in a semiconductor electronic device.

Thin ribbon of semiconductor material

A novel thin ribbon wafer of semiconductor having a polycrystalline structure composed of more than 50% of a grain having a grain size of more than 5 .mu.m, a thickness of 5 to 200 .mu.m, sufficient flexibility to be windable on a pipe having a diameter of 34 mm, malleability, and composed from p-type, i-type or n-type semiconductor material, and the composite clad of at least two elements thereof so as to form a p-n type junction. The composition of said semiconductor material consists of pure silicon or silicon with additional elements for improving the properties of a semiconductor; said additional element being at least one element in a proportion of less than 10 atomic % as compared to said silicon, said element selected from the group consisting of non-metallic elements such as hydrogen, phosphorus, sulfur and oxygen; semi-metallic elements such as boron, arsenic, tellurium, tin and selenium; metallic elements such as aluminum, gallium, indium, chromium, silver, iron and bismuth; and mixtures thereof with at least one element having smaller solubility limit than that of silicon. A method of manufacturing a thin ribbon wafer of composite clad of semiconductor material is also disclosed. Said flexible thin ribbon wafer of semiconductor is available for use as/or in a semiconductor electronic device.

Method of manufacturing a thin ribbon wafer of semiconductor material

The disclosed process produces a silicon ribbon wafer with a p-n junction, by melting a raw silicon material, ejecting the molten silicon material onto a rotary cooling member so as to produce a silicon ribbon wafer through super-rapid cooling, and applying an impurity element whose polarity is opposite to that of the raw silicon material onto the thus formed silicon ribbon wafer at a temperature of not lower than 600.degree. C. and cooled from said temperature, whereby a p-n junction is formed in the silicon ribbon wafer simultaneously with the production of the fully solidified silicon ribbon wafer.

Process of producing silicon ribbon with p-n junction

A method for manufacturing a thin and flexible ribbon wafer of semiconductor material such as germanium, silicon, selenium, tellurium, PbS, InSb, ZnTe, PbSe, InAs, InP, GaSb, PbTe, ZnS, Bi.sub.2 Te.sub.3, and mixtures thereof comprises melting the semiconductor material at a temperature within the range from a melting point thereof to 300.degree. C. above the melting point to form a uniform melt; ejecting under a pressure the melt through a nozzle against a cooling surface of a moving substrate to cool very rapidly a jet flow of the melt at a cooling rate of 1,000.degree. C. to 1,000,000.degree. C./sec to form the ribbon type thin and flexible wafer of fine and compact microscopic structure having a large mechanical strength and an excellent electrical property. It is possible to add to the melt various additives as fluxes or impurities such as B, P, BP, Sb Sn, As, B, P, Sb, In, Al and alloys intermetallic compounds, and conjugates thereof. The thin ribbon wafer as grown is preferably heated at a temperature from within the range 500.degree. C. to the melting point for a time within the range from 0.1 second to one week. The invention also provides a thin and flexible ribbon wafer of semiconductor material manufactured by the above mentioned process.

Method for manufacturing thin and flexible ribbon wafer of

A method for manufacturing a thin and flexible ribbon of superconductor material such as V.sub.3 Sn, V.sub.3 Ge, V.sub.3 Si, Nb.sub.3 Sn, Nb.sub.3 Ge, Nb.sub.3 Si and La-Au having a fine and compact microscopic structure comprises heating raw superconductor material at a temperature within the range between its melting point and 300.degree. C. above the melting point to form a melt having suitable wettability and viscosity; ejecting the melt through a nozzle under a pressure within the range from 0.01 to 1.5 atm. against a cooling surface of a moving substrate such as a rotating drum; and cooling instantaneously and very rapidly a jet flow of the melt on the cooling surface at a cooling rate of 1,000.degree. C. to 1,000,000.degree. C./sec. In order to manufacture the thin elongated ribbon of excellent configuration it is preferable to effect the cooling in a reduced atmosphere. The invention also provides the thin and flexible ribbon processed by the above mentioned process. When an intermetallic compound such as Nb-Si, Nb-Sn, Nb-Ge, V-Si, V-Sn and V-Ge is used as the raw superconductor material a thin and flexible ribbon of superconductor material having essentially a crystalline structure is formed. When La.sub.1-x (Au.sub.y Cu.sub.1-y).sub.x, wherein x&gt;0.9, 0.ltoreq.y.ltoreq.1 is used as the raw superconductor material it is possible to obtain a thin and flexible ribbon of superconductor material having essentially a fine and compact crystalline structure mixed with amorphous of 10 to 90%.

Method for manufacturing a thin and flexible ribbon of superconductor

A high silicon steel strip having excellent magnetic properties and good workability, and having a composition consisting of 4-10% by weight of silicon and the remainder being substantially iron and incidental impurities is produced by cooling super rapidly the high silicon steel melt on a cooling substrate to form a thin strip having micro-structure comprising very fine crystal grains having substantially no ordered lattice.

High silicon steel thin strips and a method for producing the same

An electric signal transmission transducer employing a ferromagnetic amorphous ribbon and especially an electric signal transmission element and system and an electroacoustic signal conversion system using a ferromagnetic amorphous ribbon. The transmission transducer also provides for applying a magnetic field to the ferromagnetic amorphous ribbon for controlling the electric signal transmission or delay time. Also shown are the electric and magnetic characteristics of ferromagnetic amorphous ribbons after various heat treatments in various magnetic fields.

Electric signal transmission device employing a ferromagnetic amorphous

A method of manufacturing a thin ribbon of magnetic material having a high permeability and excellent flexibility and workability comprising the combination of steps of

Method of manufacturing a thin ribbon of magnetic material

A method for manufacturing a thin and flexible ribbon of dielectric material comprises

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Sendai, Japan

Noboru Tsuya