Jeffrey A Goldacker

57599335, Jun 2, 1998

Jan 27, 1997

8/789699

Chien-Wei Li - Livingston NJ
John Pollinger - Redondo Beach CA
Jean Yamanis - Morristown NJ
Jeffrey A. Goldacker - Somerville NJ

AlliedSignal Inc. - Morris Township NJ

C04B 35577
C04B 35596

501 92

A silicon nitride sintered body has a composition consisting essentially of 80 to 93% by weight. beta. silicon nitride, 7 to 20% by weight grain boundary phases consisting essentially of (i) at least two rare earth elements, wherein yttrium is considered a rare earth, and strontium which, calculated as SrO, is 0. 5 to 5% by weight, and (ii) at least two of Si, N, O and C; and (c) silicon carbide particulate present in the amount of about 5 to 35 parts by weight per 100 parts by weight of components (a) and (b), said SiC being substantially homogeneously dispersed within said sintered body. Such a ceramic has high strength and long term durability, and is especially suited for industrial applications such as components for gas turbine and automotive engines.

59325070, Aug 3, 1999

Feb 19, 1998

9/026228

Remco van Weeren - Oldwick NJ
Jeffrey A. Goldacker - Findlay OH
Philip J. Whalen - Sparta NJ

C04B 3510

501105

A ceramic body having a surface region containing tetragonal zirconia is sintered to at least 95% theoretical density at a temperature below about 1550. degree. C. The surface region is then heat treated to reverse local stresses therein. Low temperature degradation in tetragonal zirconia, and materials containing tetragonal zirconia, is significantly inhibited. The heat treated ceramic is especially suited for use in structural components such as valves, engine housings, pistons (chambers) and the like which, during operation, are frequently exposed to temperatures ranging from room temperature to 500. degree. C. for prolonged periods of time.

56375409, Jun 10, 1997

Jul 23, 1993

8/096203

Chien-Wei Li - Livingston NJ
Jeffrey A. Goldacker - Somerville NJ

AlliedSignal Inc. - Morristown NJ

C04B 3558

501 972

A silicon nitride sintered body has a composition consisting essentially of 85 to 94% by weight. beta. silicon nitride, 6 to 15% by weight grain boundary phase consisting essentially of (i) at least two rare earth elements, wherein yttrium is considered a rare earth, and, optionally, strontium which, calculated as SrO, is 02 percent by weight of the total body, and (ii) at least two of Si, N, O and C, and an additive consisting essentially of a metal carbon compound present in the amount of about 0. 2 to 3. 5% by volume. The additive is substantially homogeneously dispersed within the sintered body. The sintered body has a microstructure wherein (i) the. beta. silicon nitride grains are acicular and have an average grain width ranging from 0. 5 to 1. 5. mu. m, (ii) at least 25% of the grains have width greater than 0. 7. mu. m, and at least 10% of the grains have width greater than 1. mu.