Pcc Airfoils, Inc.

Stanton Advanced Ceramics, Inc.

Other

Gerald C Dodds

Karl-Heinz Schofalvi

Ricky A Alexander

Lawrence Donald Graham

Jonathan Jarrabet

An unfired ceramic base core having a first coefficient of thermal expansion is provided. A core element having a second coefficient of thermal expansion is positioned in an opening formed in the unfired ceramic base core. The opening in the unfired ceramic base core is filled with a filler material having a third coefficient of thermal expansion. The third coefficient of thermal expansion is greater than the first coefficient of thermal expansion and less than the second coefficient of thermal expansion. The ceramic base core is fired without cracking the base core and without cracking the filler material. The ceramic base core contains silica and zircon and has a silica content of 70% or less and a zircon content of 30% or more. The core element may be formed of a ceramic material or a refractory metal.

Method of forming a cast metal article

An adjustable mold is used to mold material to form a first support. A first ceramic article is supported by the first support during firing. The adjustable mold may be adjusted and used to mold material to form a second support having a second configuration. The second support is used to support a second ceramic article during firing. The first and second supports may advantageously be formed with projections which engage the ceramic articles during firing. The length of these projections may be varied by adjusting the mold. A second adjustable mold may be used to form a first retainer which limits upward movement of the first ceramic article during firing. The second adjustable mold may be adjusted and used to form a second retainer which limits upward movement of the second ceramic article during firing.

Supporting ceramic articles during firing

The disclosed invention relates to ceramic matrix composites with ceramic fiber reinforcements.

Thermal shock resistant ceramic composites

The disclosed invention relates to a ceramic composite, comprising: reinforcement fibers, the reinforcement fibers comprising alumina, zirconia or magnesium silicate; the reinforcement fibers containing microcracking; and deposits derived from a sol comprising alumina or zirconia and optionally a rare earth oxide reacted with the reinforcement fibers. A process for making the composite is also disclosed.

A ceramic composite is able to whithstand temperatures in excess of 2200 F on a repeated basis without cracking due to thermal shock. The composite has a web of reinforcement fibers; and a matrix that substantially the web after the firing step. The matrix is formed around the web by impregnating the web with a sol containing alumina and, in some cases, rare earth oxides, and firing the composite after the impregnation. The web may be a three-dimensional orthogonal weave of the reinforcement fibers, where the fibers are a transitional phase alumina. The composite is essentially free of Group I and Group II metals and transition metal oxides. The composite may be used as a refractory brick or lining and may also be used as an insulatingmaterial due to its chemically non-reactive nature.

An improved sintered ceramic core is used in a mold during the casting of a reactive metal. Prior to sintering, the core contains ceramic material which includes yttrium aluminate and alumina (Al.sub.2 O.sub.3). It is preferred to have the ceramic material contain between 10% and 40% yttrium aluminate. Prior to sintering, the yttrium aluminate has a mean particle size of less than 20 microns and, preferably, less than 10 microns. Particularly advantageous results has been obtained by using yttrium aluminate having a mean particle size, prior to sintering, of approximately 3 microns. It is contemplated that the ceramic material will be utilized to form other articles, such as a mold, filter, or liner for a ladle, which are exposed to reactive metals during casting.

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Chardon, OH, United States of America

Gerald C Dodds