PURPOSE: To improve the service life of a plug by forming a matrix of powders of CO or Ni base alloys or composite alloys of the former alloys and forming a welded film by uniformly dispersing metal carbide powders of a specific vol. percentage into the matrix.
CONSTITUTION: A welded film is formed on the plug surface by uniformly dispersing and mixing metal carbide powders having a vol. percentage in 30W70% into a matrix consisting of Co or Ni base alloy powders or a composite alloy of the former alloys through plasma welding, etc. The film where a harder and wear resistant metal carbide in comparison with the matrix having toughness and small crack sensibility is uniformly dispersed and mixed into the matrix, so that advantages of both the materials are combined and disadvantages of the materials are eliminated. Thus, the service life of the plug is remarkably improved.
KONDO YOSHIHARU
NOMURA SHOJI
TATSUMI YOSHIHIRO
OFIC CO