Compositions: ceramic – Ceramic compositions – Refractory
Reexamination Certificate
2007-01-11
2010-12-21
Group, Karl E (Department: 1731)
Compositions: ceramic
Ceramic compositions
Refractory
C501S098300, C089S036020
Reexamination Certificate
active
07855159
ABSTRACT:
A SiAlON ceramic armor made from a starting powder mixture. The ceramic armor contains between about 60 weight percent and about 98 weight percent alpha SiAlON phase that contains an alpha SiAlON-bound rare earth element and between about 2 weight percent and about 40 weight percent of a beta SiAlON phase of the formula Si6−zAlzOzN8−zwherein the value of “z” ranges between about 0.2 and about 1.0. The ceramic armor further comprising sintering aid residue present as a result of the starting powder mixture containing between about 4 weight percent and about 14 weight percent of an oxide of an alpha SiAlON-bound rare earth element. The ceramic armor has a fracture toughness (KIC) greater than about 6.00 M·Pa m1/2and a Vickers hardness (HVN) equal to greater than about 17.5 GPa.
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Group Karl E
Kennametal Inc.
Smith Matthew W.
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