Accession Number : ADD012007

Title :   Igniter Electrode Life Control.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Scott,John C

Report Date : 07 Oct 1985

Pagination or Media Count : 11

Abstract : The prevention of electrode material erosion by undercutting in the outer electrode shell of igniter electrodes of jet engine ignition systems is prevented by the application of an electrical insulation coating. The coating is applied to the surface of the outer electrode shell which faces the ceramic insulation around the center electrode where erosion patterns are known to occur. the insulation material is selected from electrical insulation substances such as oxides of aluminum, tungsten, magnesium, beryllium or zirconium by choosing a non-porous electrical insulating substance with thermal expansion characteristics approximately equalling those of the outer electrode shell. Since a typical outer electrode shell is composed of 446 stainless steel, an optimum choice for the electrical insulation coating is AL203 deposited with a coating thickness of between 5 and 10 mils. (Author)

Descriptors :   *PATENT APPLICATIONS, *ALUMINUM OXIDES, *ELECTRIC IGNITERS, *ELECTRICAL INSULATION, EROSION RESISTANCE, CERAMIC COATINGS, STAINLESS STEEL, SURFACES, ELECTRODES, COATINGS, IGNITERS, IGNITION SYSTEMS, JET ENGINES, BERYLLIUM, INSULATION, THICKNESS, PATTERNS, MATERIALS, MAGNESIUM, EXTERNAL, ALUMINUM, OXIDES, TUNGSTEN, SHELLS(STRUCTURAL FORMS), THERMAL EXPANSION, ZIRCONIUM

Subject Categories : Coatings, Colorants and Finishes
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE