Hidetsugu Kawabata

Method of making metal coated foil speaker diaphragm

A speaker diaphragm of the present invention is prepared in a manner such that a boron layer is formed on one face of a dome-shaped metal foil by means of a physical vapor deposition method such as ion-plating, cathode sputtering, vacuum evaporation or the like, when necessary the metal foil is thinned by etching, and then, if necessary, another boron layer is formed on the other face of the metal foil. Alternatively, a metal layer is formed on the surface of the boron layer. The resultant speaker diaphragm is light in weight and high in modulus and also has appropriate internal mechanical resistance against vibration, thereby providing a speaker of high efficiency and satisfactory characteristics.

Composite diaphragm for speaker

A composite diaphragm for a speaker comprises a boron layer formed on a metal foil such as titanium foil, in which a layer of a low melting point metal such as aluminum or magnesium is interposed between the metal foil and the boron layer to provide high rigidity, high elasticity and high bonding strength between the metal foil and the boron layer.

MSR and land/groove recording combined

This paper describes the combining of MSR and land/groove recording. The combination of MSR and shallow groove type land/groove recording gives excellent results. Double mask type MSR has the advantage of limiting crosstalk, regardless of type of shallow groove. At narrow track pitches, cross-erasing is a greater problem than crosstalk. We attempted a pulse train erasing method to reduce cross-erasing. As a result, an erasing power allowance of /spl plusmn/20% was achieved with a track pitch of 0.65 /spl mu/m using a NA0.55 magneto-optical head with a LD wavelength of 680 nm.

The solid boriding of permalloy for magnetic head application

Abstract The solid bonding of Permalloy with a powder mixture of boron carbide and accelerators was studied for magnetic head application. Heat treatments were carried out in the temperature range 800 – 1050 °C in a muffle furnace. The effects of temperature, heating period, atmosphere and the content of bonding accelerators, such as Na 2 CO 3 and Na 2 B 4 O 7 , on the thickness of the boride layer were investigated by using microscopic examination and X-ray microanalysis. At the optimum condition, a boride layer over 200 μm thick was formed within several hours through treatment at 1000 °C in an H 2 atmosphere. The main composition of the boride layer formed on the Permalloy was Ni 2 B and the microhardness Hv was 800 – 1000 (with a 100 g load). It was found that the wear resistance of the boronized Permalloy thus formed was approximately six times greater than that of regular Permalloy.

The growth of boron films by physical vapour deposition

Abstract In spite of the fact that the growth of boron films has always been very difficult because of the high melting point of boron, we investigated the growth of thin films of boron. The boron films were prepared on a titanium substrate by an ion plating method. The morphology of films grown by this method was studied. From electron microscope studies it was shown that the properties of the films depend on the deposition rate and the substrate temperature.

Structures and Material Characteristics of Magneto-Optical Disks

The effect of different methods of applying SiO protective layers to magneto-optical disks are discussed. These layers were applied using resistance heating (RH) evaporation, electron beam (EB) evaporation and sputtering. Compositional disparity was observed between the applied films and their sources for each of the different application methods. This disparity was largest with sputtering and smallest with RH evaporation. The aging of the Kerr rotation angle of magneto-optical disks with SiO protective layers also showed a similar correspondence. The continuous production of films with SiO protective layers in a vacuum lowered deterioration levels and inhibited pitting corrosion.