Igniter electrode life control

Patent · Mon Oct 07 04:00:00 EDT 1985

OSTI ID:5905893

Scott, J C

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 Al/sub 2/O/sub 3/ deposited with a coating thickness of between 5 and 10 mils.

• Assignee: Dept. of the Air Force, Washington, DC
• Patent Number(s): None
• OSTI ID: 5905893
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360205* -- Ceramics
Cermets
& Refractories-- Corrosion & Erosion
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BERYLLIUM COMPOUNDS
BERYLLIUM OXIDES
CHALCOGENIDES
CHROMIUM ALLOYS
CHROMIUM STEELS
COATINGS
CORROSION RESISTANT ALLOYS
DIMENSIONS
ELECTRICAL INSULATION
ELECTRODES
ENGINES
EXPANSION
IGNITION SYSTEMS
IRON ALLOYS
IRON BASE ALLOYS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS
OXIDES
OXYGEN COMPOUNDS
PROTECTIVE COATINGS
REFRACTORY METAL COMPOUNDS
STAINLESS STEEL-446
STAINLESS STEELS
STEELS
SURFACES
THERMAL EXPANSION
THICKNESS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
TUNGSTEN OXIDES
TURBOJET ENGINES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES