Hot surface igniters and methods of making same
AssigneeSpecialized Component Parts Limited, Inc.
InventorsCraig Andrew Willkens, Frederick Taylor Fernandez
Life of this patent
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Abstract
A method of making a hot surface igniter is described. A silicon carbide composition that includes both fines fraction and a coarse fraction is sintered in a nitrogen and argon reducing atmosphere in a manner that controls the incorporation of nitrogen with in the lattice of recrystallized silicon carbide. The controlled incorporation of nitrogen in the lattice provides enhanced control over heating and electrical properties, while simultaneously achieving a lower surface area fully recrystallized structure for oxidation resistance and long service life.
Claims19
A method of making a sintered hot surface igniter body, comprising:
- providing an unsintered, hot surface igniter body comprising silicon carbide, wherein the unsintered hot surface igniter body has a green density of greater than about 70 percent of a theoretical maximum density;
- sintering the unsintered hot surface igniter in a reducing atmosphere comprising nitrogen in an amount ranging from about 20 mole percent to about 80 mole percent of the reducing atmosphere to yield a sintered hot surface igniter body, wherein the sintered hot surface igniter body has a post sintering density that differs from the green density by no more than about five (5) percent, and the step of sintering the unsintered hot surface igniter body in a reducing atmosphere comprises sintering the hot surface igniter body at one or more sintering temperatures ranging from about 2075° C. to about 2425° C. for a sintering period of from about 20 minutes to about 150 minutes.
Dependencies are inferred from the claim text.