ELECTRODE TIP FOR SPARK PLUG

• Main Authors: MORINO TOSHIYUKI, KOIKE SATOSHI
• Format: Patent
• Language: English
• Published: 31.08.2006
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; CORONA DEVICES; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARK GAPS; SPARKING PLUGS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To provide an electrode tip for a spark plug which is suppressed in high temperature volatilization wear than an inclination functional material layer formed by a thermal diffusion method, improved in durability with respect to spark wear by improving high temperature strength of the electrode tip, and realizes low cost, by suppressing the amount of precious metal used by further realizing thin diameter. SOLUTION: As for the electrode tip for spark plug, when a protective film, consisting of an alloy having iridium and rhodium as the main components, is coated on a surface of a core material made of iridium or an iridium alloy, the protective film is formed by a gas-phase method, and the composition of the protective film is made to be iridium only or mainly iridium on the surface of the core material, and along the film growth direction, rhodium content is made to increase continuously and/or in stepwise manner, and iridium content is made to decrease continuously and/or in stepwise manner, and on the outermost surface, rhodium is made to be contained by 75-100 wt%. COPYRIGHT: (C)2006,JPO&NCIPI