High temperature ceramic material suitable for gas turbine applications and a process for producing same
AssigneeFord Motor Company
InventorsMorton E. Milberg, Wayne M. Miller
Life of this patent
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Abstract
A method of making improved SIALON ceramics without the need for hot pressing, is disclosed. A homogeneous slip is prepared from Si.sub.3 N.sub.4, Al.sub.2 O.sub.3 and Y.sub.2 O.sub.3 in the presence of a suspension agent; Y.sub.2 O.sub.3 being present in at least 1% by weight (preferably between 1-25%) and Al.sub.2 O.sub.3 being present in the range 16-40% by weight (preferably 16-18%). The slip is cast and dehydrated. The cast shape is reaction sintered at about 1550.degree.-1700.degree. C (preferably 1600.degree. C) for no less than 3 hours (preferably between 3-12 hours).
Claims2
A method of making ceramics, comprising:
- a. compact a desired powdered shape from a mixture of 99.9% pure Si.sub.3 N.sub.4 powder, Al.sub.2 O.sub.3 powder, and Y.sub.2 O.sub.3 powder, said Y.sub.2 O.sub.3 being present in said mixture at about essentially a 3% additive by weight and said Al.sub.2 O.sub.3 being present in an amount at about essentially 16% by weight
- b. with the absence of pressure, heat said shape to a temperature between 1550.degree.-1700.degree. C and hold at said temperature for a period of time at about essentially 12 hours, the resulting ceramic exhibiting a transverse rupture strength of at least 80,000 psi.
A method of making ceramics, comprising:
- a. compact a desired powdered shape from a mixture of Si.sub.3 N.sub.4 powder, Al.sub.2 O.sub.3 powder, and Y.sub.2 O.sub.3 powder, said Y.sub.2 O.sub.3 being present in said mixture as about essentially a 3% additive by weight and said Al.sub.2 O.sub.3 being present in an amount essentially about 16% by weight,
- b. With the absence of pressure, heat said shape to a temperature between 1550.degree.-1700.degree. C and hold at said temperature for a period of time between 3-12 hours, said resulting ceramic exhibiting substantially a single phase and having a room temperature transverse rupture strength of at least 45,000 psi.
Dependencies are inferred from the claim text.