Ceramic cores for casting of reactive metals

• US 5,712,435 A
• Filed: 06/01/1995
• Issued: 01/27/1998
• Est. Priority Date: 01/28/1987
• Status: Expired due to Term

• Current Assignee: Remet Pic, Inc.
• Original Assignee: REMET Corp.
• Inventors: Feagin, Roy C.
• Primary Examiner(s): Nelson, Peter A.
• Application Number:
  US08/456,323
• Time in Patent Office: 971 Days
• Field of Search: 164/139, 164/519, 106/38.22, 75/230
• US Class Current: 75/230
• CPC Class Codes: B22C 1/00 Compositions of refractory mould or core materials; Grain structures thereof refractory materials in general C04B35/00; Chemical or physical features in the formation or manufacture of moulds
• CPC Class Codes: B22C 1/165 in the manufacture of multilayered shell moulds
• CPC Class Codes: B22C 3/00 Selection of compositions for coating the surfaces of moulds, cores, or patterns
• CPC Class Codes: C04B 12/00 Cements not provided for in groups C04B7/00 - C04B11/00
• CPC Class Codes: C04B 14/30 Oxides other than silica ferrites C04B14/363
• CPC Class Codes: C04B 2103/0093 Organic cosolvents
• CPC Class Codes: C04B 2111/00482 Coating or impregnation materials
• CPC Class Codes: C04B 2111/00879 Non-ferrous metallurgy
• CPC Class Codes: C04B 2111/00939 for the fabrication of moulds or cores
• CPC Class Codes: C04B 22/082 Acids
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3244 Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/668 Pressureless sintering
• CPC Class Codes: C04B 24/04 Carboxylic acids; Salts, anhydrides or esters thereof
• CPC Class Codes: C04B 28/00 Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
• CPC Class Codes: C04B 35/505 based on yttrium oxide
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/62222 obtaining ceramic coatings coating of mortars, concrete, artificial or natural stone or ceramics C04B41/45; laminated ceramic products B32B18/00; coating metallic materials C23; coating of glass C03C17/00, applying ceramic coatings on silicon for semi-conductor purposes H01L
• CPC Class Codes: C04B 35/6303 Inorganic additives
• CPC Class Codes: C04B 35/632 Organic additives
• CPC Class Codes: C04B 35/66 : Monolithic refractories or refractory mortars, including those whether or not containing clay making or repairing of linings F27D1/16

Abstract

Cores that are relatively unreactive with titanium and titanium alloys during casting are prepared from yttria slurries, which may contain other refractory materials, an acid and an inert organic solvent.

Claims

1. A refractory core made from a refractory composition including a slurry of yttria, an acid and an inert organic solvent.

3. A refractory core according to claim 1, wherein the core is a shaped core.

4. A refractory core according to claim 1, wherein the refractory composition includes an additional material selected from the group consisting of yttrium oxide, zirconium oxide, fused yttrium oxide, fused zirconium oxide, fused stabilized zirconium oxide, and a fused homogeneous mixture of yttrium oxide and zirconium oxide.

5. A refractory core according to claim 4, wherein the refractory composition contains a minor amount of water.

6. A refractory core according to claim 1, wherein the refractory composition includes an additional material selected from the group consisting of monoclinic zirconium oxide, yttrium oxide, cubic zirconium oxide, fused yttrium oxide, fused zirconium oxide, and fused stabilized zirconium oxide.

7. A refractory core according to claim 6, wherein fused stabilized zirconium oxide is present having as a stabilizing agent a member selected from the group consisting of calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, dysprosium oxide, and oxides of other rare earth elements from the Periodic Table with an atomic number of 57 to 71, blends of zirconium oxide and yttrium oxide, and fused blends of zirconium and/or yttrium oxide with other oxides of a rare earth element from the Periodic Table with an atomic number of 57 to 71.

8. A refractory core according to claim 1, wherein the acid is an organic acid or an inorganic acid, and wherein the acid is capable of reacting with the yttria in the slurry to form a salt that will hydrate in the presence of moisture.

9. A refractory core according to claim 1, wherein the solvent is an alkanol or a ketone.

2. A refractory foundry core made from a refractory composition including a slurry of yttria, an acid and an inert organic solvent.

10. A refractory foundry core according to claim 2, wherein the refractory composition includes an additional material selected from the group consisting of yttrium oxide, zirconium oxide, fused yttrium oxide, fused zirconium oxide, fused stabilized zirconium oxide, and a fused homogeneous mixture of yttrium oxide and zirconium oxide.

11. A refractory foundry core according to claim 10, wherein the refractory composition contains a minor amount of water.

12. A refractory foundry core according to claim 2, wherein the refractory composition includes an additional material selected from the group consisting of monoclinic zirconium oxide, yttrium oxide, cubic zirconium oxide, fused yttrium oxide, fused zirconium oxide, and fused stabilized zirconium oxide.

13. A refractory foundry core according to claim 12, wherein fused stabilized zirconium oxide is present having as a stabilizing agent a member selected from the group consisting of calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, dysprosium oxide, and oxides of other rare earth elements from the Periodic Table with an atomic number of 57 to 71, blends of zirconium oxide and yttrium oxide, and fused blends of zirconium and/or yttrium oxide with other oxides of a rare earth element from the Periodic Table with an atomic number of 57 to 71.

14. A refractory foundry core according to claim 2, wherein the acid is an organic acid or an inorganic acid, and wherein the acid is capable of reacting with the yttria in the slurry to form a salt that will hydrate in the presence of moisture.

15. A refractory foundry core according to claim 2, wherein the solvent is an alkanol or a ketone.