Ted R Crego

US Patent:

54070015, Apr 18, 1995

Filed:

Jul 8, 1993

Appl. No.:

8/089259

Inventors:

Mehrdad Yasrebi - Clackamas OR
William W. Kemp - Milwaukie OR
David H. Sturgis - Gladstone OR
Douglas G. Nikolas - Battleground WA
Gary L. Wright - Brush Prairie WA
Thomas J. Kelly - Gresham OR
Mark E. Springgate - Portland OR
Ted R. Crego - Gladstone OR

Assignee:

Precision Castparts Corporation - Portland OR

International Classification:

B22C 106
B22C 904

US Classification:

164519

Abstract:

The disclosure describes an aqueous ceramic slurry having from about 70-weight percent to about 85 weight-percent of a fused yttria-zirconia material. The weight percent of zirconia in the fused yttria-zirconia preferably varies from about 1. 0 weight percent to about 10. 0 weight percent. Fused slurries may comprise, in addition to fused yttria-zirconia, an inorganic binder (preferably silica), an organic binder (preferably a latex binder), a surfactant (preferably a sodium dioctyl sulfosuccinate), an antifoaming agent (preferably a water-dilutable active silicone defoamer) and titanium dioxide. The slurries of the present invention are used to form ceramic mold facecoatings for casting reactive materials. These slurries are less sensitive to pH fluctuations than are slurries made from 100 percent yttria (yttria slurries). Moreover, slurries as described in the disclosure do not gel prematurely, and exhibit substantially the same formation of oxygen-enriched titanium (alpha case) than do yttria slurries.

US Patent:

54647975, Nov 7, 1995

Filed:

Dec 5, 1994

Appl. No.:

8/349257

Inventors:

Mehrdad Yasrebi - Clackamas OR
William W. Kemp - Milwaukie OR
David H. Sturgis - Gladstone OR
Douglas G. Nikolas - Battleground WA
Gary L. Wright - Brush Prairie WA
Thomas J. Kelly - Gresham OR
Mark E. Springgate - Portland OR
Ted R. Crego - Gladstone OR

Assignee:

Precision Castparts Corporation - Portland OR

International Classification:

C04B 35505
C22C 100
C22C 300

US Classification:

501103

Abstract:

The disclosure describes an aqueous ceramic slurry having from about 70-weight percent to about 85 weight-percent of a fused yttria-zirconia material. The weight percent of zirconia in the fused yttria-zirconia preferably varies from about 1. 0 weight percent to about 10. 0 weight percent. Fused slurries may comprise, in addition to fused yttria-zirconia, an inorganic binder (preferably silica), an organic binder (preferably a latex binder), a surfactant (preferably a sodium dioctyl sulfosuccinate), an antifoaming agent (preferably a water-dilutable active silicone defoamer) and titanium dioxide. The slurries of the present invention are used to form ceramic mold facecoatings for casting reactive materials. These slurries are less sensitive to pH fluctuations than are slurries made from 100 percent yttria (yttria slurries). Moreover, slurries as described in the disclosure do not gel prematurely, and exhibit substantially the same formation of oxygen-enriched titanium (alpha case) than do yttria slurries.