Apparatus for ion-nitriding treatment

Claim 1

In an apparatus for ion-nitriding a workpiece, said apparatus having: a vacuum reacting furnace adapted to receive said workpiece; a heat-producing element inside said vacuum reacting furnace; an inner wall screening body between said heat-producing element and said workpiece for electrically screening said heat-producing element from said workpiece; a first power source connected between said screening body and said workpiece for creating glow discharge by impressing DC voltage between said screening body as an anode and said workpiece as a cathode; and a second power source connected to said heat-producing element for heating said heat-producing element by impressing AC voltage upon said heat-producing element, whereby said workpiece is heated and ion-nitrided by the combined use of said glow discharge and heat generated by said heat-producing element; an improvement comprising: control means connected to said first and second power sources for controlling the temperature inside said furnace by concurrently controlling the voltage impressed from said first and second power sources in relation to the temperature inside said furnace, whereby the heat generated by said heat-producing element and the heat generated during glow discharge are maintained at desired levels, said voltage impressed by said second power source to said heat-producing element having a maximum value of 220 volts.