Matsushita Electric Industrial Co., Ltd.

Isami Saito

Yasuhiro Shindo

Yukio Tsujimoto

Hiroshi Hirayama

Isamu Hiraoka

Disclosed is a method of heat treatment of a low melting-point metal for production of spheroidal bodies formed of a low melting-point metal or alloy or heat treatment of the low-melting point metal coated on the surface of an electrode of a chip part. The method comprises the steps of placing a high boiling-point liquid, such as oil, into a tubular container disposed vertically and provided with a heater at an upper portion thereof, the high boiling-point liquid being provided with a temperature gradient ranging from a high temperature above the melting point of the metal to be subjected to heat treatment to a low temperature below the melting point thereof; and allowing the low melting-point metal or a low melting-point alloy per se or a material having the low melting-point metal or alloy on its surface to move from the high-temperature portion of the high boiling-point liquid; whereby the low melting-point metal or a low melting-point alloy per se or a material having the low melting-point metal or alloy on its surface is made to melt in the high-temperature portion and is cooled in the low-temperature portion, thereby allowing a melt or a molten portion to solidify.

Method of heat treatment of low melting-point metal on an electrode of a

The invention is directed to the electrode structure of a chip type component, such as a chip resistor, in which a plated film of low melting point metal is used as an outermost coating electrode film on the electrode portion, the layer underlying said plated film of low melting point metal on the electrode portion is formed of a metal material having a higher melting point than that of the plated film and also having good affinity with said plated film, and the electrode material comprising said plated film of low melting point metal is subjected to heat treatment at a temperature higher than the melting point thereof, so that the outermost surface of the electrode portion is coated with a remolten metal film.

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Fukui, Japan

Isami Saito