Hitachi, Ltd.

Sizuka Yamaguchi

Katsuyoshi Terakado

Naotatsu Asahi

A glow discharge surface treatment process wherein only the selected portions of a workpiece adjacent to or surrounded by the associated secondary electrodes are surface-treated so as to provide different treatments on the workpiece according to the position of the secondary electrodes. The each secondary electrode is provided close to at least a portion of the workpiece, and the workpiece and the associated secondary electrode are both connected to the cathode. When a voltage is applied between the cathode and the wall of the container in the treatment apparatus which forms the anode, mutual interference effect (which is referred to as a hollow cathode effect) of negative glow discharges is established between the workpiece and the associated secondary electrode so as to accelerate the heat treatment for the selected portion of the workpiece surrounded by the secondary electrode. The gas pressure in the container is varied to control the hollow cathode effect. In the treatment process of the present invention, the workpiece is thermally treated so as to provide differently treated portions therein.

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Hitachi, Japan

Sizuka Yamaguchi