ELECTRIC DISCHARGE SURFACE TREATING METHOD AND ELECTRIC DISCHARGE SURFACE TREATING APPARATUS

摘要

It is possible to obtain an electric discharge surface treating method and an electric discharge surface treating apparatus capable of forming a dense and relatively thick film coating. When a voltage is applied to the inter-electrode gap between an electric discharge electrode (21) and a work (22) from a first power supply (23) and an electric discharge occurs, a voltage for generating a second electric discharge current is supplied to the inter-electrode gap from a second power supply (28) for a short period of time. The second electric discharge current is superimposed on a first discharge current generated by the first power supply (23) and has a larger current value than the first current. This allows an electric discharge pulse current of a high-current value and a short pulse width having a rising speed of at least 40 A/µs or more to flow through the inter-electrode gap. As a result, only a necessary part of the electrode material is quickly melted and a large ratio of the melted electrode material can be contained in the electrode material migrating to the work side by the thermal energy of electric discharge or a compound of the electrode material, so that a film coating of the melted metal is formed on the surface of the work.