Electrode for discharge surface treatment, manufacturing method and evaluation method for electrode for discharge surface treatment, discharge surface treatment apparatus, and discharge surface treatment method

Abstract

An electrode is used to perform discharge surface treatment of a work piece. The electrode is made of a green compact obtained by compression-molding an electrode material including powder of any of a metal, a metallic compound, and ceramics. The discharge surface treatment includes generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film consisting of a machining material on a surface of a work piece using energy produced by the electric discharge. The powder has an average particle diameter of 5 micrometer to 10 micrometers, and contains 40 volume percent or more of a component not forming or less easily forming carbide as a component for forming the film on the work piece. The electrode has a hardness in a range of B to 8B tested with a pencil scratch test for a coating film.

1 . An electrode for discharge surface treatment of a work piece, the electrode being made of a green compact obtained by compression-molding an electrode material including powder of any of a metal, a metallic compound, and ceramics, and the discharge surface treatment generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film consisting of a machining material on a surface of a work piece using energy produced by the electric discharge, wherein
 the powder has an average particle diameter of 5 micrometer to 10 micrometers, and contains 40 volume percent or more of a component not forming or less easily forming carbide as a component for forming the film on the work piece; and   the electrode has a hardness in a range of B to 8B tested with a pencil scratch test for a coating film.   
   
   
       2 . The electrode according to  claim 1 , wherein the component not forming carbide or less easily forming carbide is selected from a group consisting of Co, Ni, Fe, Cu, and Zn. 
   
   
       3 . An electrode for discharge surface treatment of a work piece, the electrode being made of a green compact obtained by compression-molding an electrode material including powder of any of a metal, a metallic compound, and ceramics, and the discharge surface treatment generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film consisting of a machining material on a surface of a work piece using energy produced by the electric discharge, wherein
 the powder has an average particle diameter of 1 micrometer to 5 micrometers and contains 40 volume percent or more of a component not forming or less easily forming carbide as a component for forming the film on the work piece; and   the electrode has a hardness in a range of 20 to 50 in hardness H=100−1000×h calculated when a press-in distance at the time when a steel ball with a diameter of ¼ inch is pressed against the electrode at 15 kgf is h (μm).   
   
   
       4 . The electrode according to  claim 3 , wherein the component not forming carbide or less easily forming carbide is selected from a group consisting of Co, Ni, Fe, Cu, and Zn. 
   
   
       5 . An electrode for discharge surface treatment of a work piece, the electrode being made of a green compact obtained by compression-molding an electrode material including powder of any of a metal, a metallic compound, and ceramics, and the discharge surface treatment generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film consisting of a machining material on a surface of a work piece using energy produced by the electric discharge, wherein
 the powder has an average particle diameter of not more than 1 micrometer and contains 40 volume percent or more of a component not forming or less easily forming carbide as a component for forming the film on the work piece; and   the electrode has a hardness in a range of 25 to 60 in hardness H=100−1000×h calculated when a press-in distance at the time when a steel ball with a diameter of ¼ inch is pressed against the electrode at 15 kgf is h (μm).   
   
   
       6 . The electrode according to  claim 5 , wherein the component not forming carbide or less easily forming carbide is selected from a group consisting of Co, Ni, Fe, Cu, and Zn. 
   
   
       7 . An electrode for discharge surface treatment of a work piece, the electrode being made of a green compact obtained by compression-molding an electrode material including powder of any of a metal and a metallic compound, and the discharge surface treatment generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film of a machining material on a surface of a work piece using energy produced by the electric discharge, wherein when an average particle diameter of the powder is plotted on a logarithmic scale in micrometers and a compression strength used in the compression-molding is plotted on a normal scale in MPa, the compression strength used in the compression-molding is lower than a compression strength represented by a line on the plot obtained by joining points
 average particle diameter: 0.05 micrometer, compression strength: 160 MPa,   average particle diameter: 1 micrometer, compression strength: 100 MPa, and   average particle diameter: 3 micrometers, compression strength: 50 Mpa.   
   
   
       8 . The electrode according to  claim 7 , wherein the powder in selected from a group consisting of Co powder, Co alloy powder, Ni powder, or Ni alloy powder. 
   
   
       9 . An electrode for discharge surface treatment of a work piece, the electrode being made of a green compact obtained by compression-molding an electrode material including powder of any of a metal and a metallic compound, and the discharge surface treatment generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film consisting of a machining material on a surface of a work piece using energy produced by the electric discharge, wherein
 a volume ratio of the electrode material to the electrode is within a specific range between 25% to 65% depending on a distribution of a particle diameter of the powder, and   the volume ratio is set high when the distribution of particle diameter is wide and the volume ratio is set low when the distribution of particle diameter is narrow.   
   
   
       10 . The electrode according to  claim 9 , wherein the electrode material contains 40 volume percent or more of a material less easily forming carbide. 
   
   
       11 . The electrode according to  claim 9 , wherein the electrode material is metal powder or powder of a metallic compound with an average particle diameter not more than 3 micrometers. 
   
   
       12 . The electrode according to  claim 9 , wherein the electrode material is a Co-based alloy containing any one of Cr, Ni, and W. 
   
   
       13 . An electrode for discharge surface treatment of a work piece, the electrode being made of a green compact obtained by compression-molding an electrode material including powder of any of a metal and a metallic compound, and the discharge surface treatment generating an electric discharge between the electrode and the work piece in an atmosphere of a machining medium and forming a film of a machining material on a surface of a work piece using energy produced by the electric discharge, wherein
 a thermal conductivity of the electrode is not more than 10 W/mK.   
   
   
       14 . The electrode according to  claim 13 , wherein powder obtained by grinding to refine the metal powder or the powder of the metallic compound with an average particle diameter not more than 3 micrometers is used. 
   
   
       15 . The electrode according to  claim 13 , wherein the powder of the metallic compound is selected from a group consisting of Co alloy, Ni alloy, or Fe alloy.