Process for sintering extruded powder shapes
AssigneeKennecott Corporation
InventorsJonathan J. Kim, Viswanathan Venkateswaran
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Abstract
An improved process for sintering extruded powder shapes comprising drying or calcining an extruded shape in a microwave furnace and rapid sintering the shape in a plasma fired furnace. Alternatively, calcining or drying may take place within a furnace heated by the plasma furnace's exhaust. The process of the invention is especially useful for silicon carbide extruded materials and for tubular shapes. This process significantly reduces sintering times and costs. Use of the process yields a high strength sintered product.
Claims28
A process for sintering extruded powder materials comprising the following steps:
- (a) drying or calcining an extruded powder shape;
- (b) enclosing said extruded powder shape within a graphite shroud;
- (c) affixing the ends of said graphite shroud to a holding means to form an assembly by fastening one end of said graphite shroud to one holding means, and fastening the other end of said graphite shroud to a second holding means;
- and
- (d) rapid sintering said graphite enclosed extruded shape in a plasma fired tube furnace.
A process for sintering extruded silicon carbide tubes in a plasma fired tube furnace comprising the following steps:
- (a) drying or calcining extruded silicon carbide tubes in a microwave furnace;
- (b) enclosing said silicon carbide tubes within thin-walled graphite tubes;
- (c) affixing the ends of said graphite tubes to holding means to form an assembly by fastening one end of each of said graphite tubes to one holding means, and fastening the other end of each of said graphite tubes to a second holding means;
- and,
- (d) sintering said tubes in a plasma fired tube furnace having a heating rate of greater than 2000.degree. C./hour by pushing said assembly through said plasma fired tube furnace at a push rate of greater than 3 inches/minute.
A silicon carbide tube produced in accordance with the following steps:
- (a) drying or calcining an extruded silicon carbide tube in a microwave furnace;
- and,
- (b) sintering said tube in a plasma fired tube furnace having a heating rate of greater than 2000.degree. C./hour by pushing said tube through said tube furnace at a push rate of greater than 3 inches/minute.
Dependencies are inferred from the claim text.