Keizo Ishiwatari

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.

Growth of Crystalline Silicon Films on Polycrystalline Substrate

Crystalline films of silicon were prepared on a tungsten substrate by vacuum evaporation. The method used here was evaporation of silicon on a tungsten substrate, on which thin gold film was predeposited, keeping the substrate at 600–800°C. Growth of plane crystals or whisker crystals was observed depending on growth conditions such as substrate temperature, thickness of gold film and evaporation rate. The sizes of grown plane crystals were as large as several hundreds microns. Their orientation is (111) plane parallel to the substrate and their conductivity is n-type. The details of the growing technique and the examination of grown films will be explained and growth mechanism will be discussed.

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.

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.