Powder investment casting binder and molds derived therefrom
AssigneeIC Ceramic Consulting, LLC
InventorDavid B. Price
Life of this patent
Estimating the term…
Abstract
A powder binder product for use in making a slurry for investment casting molds comprising Nano-sized powders; and an organic polymer powder, wherein it does not require aqueous colloidal silica to produce slurries used to build investment casting molds. The Nano-sized powders comprise fumed alumina, boehmite, fumed silica, or fumed titanium oxide or combinations thereof. The coarse refractory powder, combined with the powder binder for mold manufacture, comprises milled zircon, tabular alumina or fused alumina, fused silica, alumino-silicate, zirconia, and yttria or combinations thereof. The organic polymer in a powder binder comprises a cellulose-based material. A powder investment casting binder, that once fired, consists of up to 96 weight percent aluminum oxide.
Claims18
A powder binder product for use in making a slurry for investment casting molds comprising:
- Nano-sized powders;
- and
- an organic polymer powder;
- wherein the composition of the Nano-sized powder comprises:
- boehmite or pseudo boehmite, 71% to 94% by weight;
- aluminum oxide;
- silicon oxide, 2.5% to 23% by weight;
- titanium oxide, 0.4% to 1.0% by weight;
- or
- combinations thereof;
- and
- wherein the powder binder product does not comprise aqueous colloidal silica to produce slurries used to build investment casting molds.
A method for producing an investment casting comprising:
- obtaining a dry powder (605) comprising:
- fumed alumina, boehmite, 71% by weight to 94% by weight;
- fumed silica, or fumed titanium oxide, 0.4% by weight to 1.0% by weight, or combinations thereof;
- aluminum oxide, zircon, mullite, alumino-silicate, zirconium oxide, yttrium oxide, silicon oxide, 2.5% by weight to 23% by weight, or combinations thereof;
- wherein said aluminum oxide, zircon, mullite, alumino-silicate, zirconium oxide, yttrium oxide, silicon oxide, or combinations thereof are added as −325 and −120 flours to make the slurry;
- and
- a cellulose-based material;
- obtaining water (610) and buffering said water;
- combining said dry powder and said buffered water to form a slurry or sol only (615);
- adjusting the pH of said slurry (620);
- providing a pattern (630);
- applying said slurry with a stucco to said pattern to create a mold (635);
- allowing said mold to harden (640);
- removing said pattern from said mold (645);
- filling said mold with molten casting material (650);
- allowing said casting material to solidify (655);
- and
- removing said mold from a cast article (660).
A method for producing an investment casting comprising:
- obtaining a dry powder binder (605) comprising fumed alumina, boehmite, fumed silica, or fumed titanium oxide or combinations thereof, and aluminum oxide, zircon, mullite, alumino-silicate, zirconium oxide, yttrium oxide, silicon oxide, or combinations thereof, and a methylcellulose cellulose-based material;
- obtaining (deionized) water (610) and buffering said deionized water with nitric acid to a pH between about 3.0 and about 5.0;
- combining said dry powders and said buffered water to form a slurry (615);
- adjusting pH of said slurry as-needed to an about 3.5 to about 5.0 range (620);
- providing a pattern (630);
- applying said slurry with a stucco to said pattern to create a mold (635);
- allowing said mold to harden (640);
- removing said pattern from said mold by flash-fire (645);
- firing said mold to between 1,000 and 1,200 deg C;
- filling said mold with molten casting material (650);
- allowing said casting material to solidify (655);
- and
- removing said mold from a cast article (660).
Dependencies are inferred from the claim text.