Yttria-zirconia slurries and mold facecoats for casting reactive metals

US5464797A · kind A · utility

Assignee

• Precision Castparts Corp. · US

Inventors

• Mehrdad Yasrebi · Sandy, US
• William W. Kemp · Milwaukie, US
• David H. Sturgis · Gladstone, US
• Douglas Gene Nikolas
• Gary L. Wright · Battle Ground, US
• Thomas J. Kelly, III · Gresham, US
• Mark E. Springgate · Portland, US
• Ted R. Crego · Gladstone, US

Key dates

• Filing date: Dec 5, 1994
• Grant date: Nov 7, 1995
• Expiry date: Dec 5, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B2235/762
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

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.