Ion Nitriding Method

Abstract

When a metal material such as an Fe alloy or Ni alloy is heated in the presence of an amino resin such as a melamine-formalin resin, a passivation film on the surface of the metal material is reduced and removed. During the reduction and removal of the passivation film, hydrogen sputtering may be also performed when the temperature becomes higher than 400° C., preferably not less than 450° C. By performing a glow discharge, the metal material having an exposed active metal surface is nitrided with N liberated from the amino resin. For example, the amino resin is applied onto the surface of the metal material directly or by using a solvent such as water.

1 . An ion nitriding method comprising applying electricity to a metal material, thereby generating glow discharge to carry out a nitriding treatment on said metal material, wherein said metal material is ion-nitrided in the presence of an amino resin in said nitriding treatment. 
   
   
       2 . An ion nitriding method according to  claim 1 , wherein said amino resin is applied to a surface of said metal material before said nitriding treatment. 
   
   
       3 . An ion nitriding method according to  claim 2 , wherein said amino resin is applied to said surface of said metal material using a solvent. 
   
   
       4 . An ion nitriding method according to  claim 1 , wherein said amino resin and said metal material are placed in a heat treatment furnace before said nitriding treatment. 
   
   
       5 . An ion nitriding method according to  claim 1 , wherein said amino resin is a melamine resin, a urea resin, an aniline resin, or a formalin resin. 
   
   
       6 . An ion nitriding method according to  claim 5 , wherein said melamine resin contains a repeating unit having a composition formula of C 6 H 3 N 9 . 
   
   
       7 . An ion nitriding method according to  claim 1 , wherein a heat treatment furnace is used as an anode and said metal material is used as a cathode to apply said electricity.