Ceramic foam

• US 4,803,025 A
• Filed: 04/23/1984
• Issued: 02/07/1989
• Est. Priority Date: 04/23/1984
• Status: Expired due to Fees

• Current Assignee: First Union National Bank Of North Carolina (Wells Fargo & Company)
• Original Assignee: Swiss Aluminium, Ltd.
• Inventors: Brockmeyer, Jerry W.
• Primary Examiner(s): SCHOR, KENNETH M
• Application Number:
  US06/602,683
• Time in Patent Office: 1,751 Days
• Field of Search: 210/510.1, 55/523, 501/80, 501/119, 266/227, 266/229, 266/230, 266/231, 264/44, 264/43, 264/59, 264/63
• US Class Current: 264/610
• CPC Class Codes: B01D 39/2093 Ceramic foam
• CPC Class Codes: C04B 38/0615 the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles C04B38/0022 takes precedence
• CPC Class Codes: C22B 9/023 By filtering filtration of aluminium C22B21/066
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

Disclosed is a ceramic foam material and process for making same having superior strength and chemical durability properties wherein the impregnated foam impregnated with a phosphate bonded ceramic is fired at an elevated temperature so as to produce a ceramic body substantially free of phosphate and having individual grains of ceramic tightly coalesced to minimize porosity between the grains.

Claims

1. A process for preparing a ceramic foam filter for filtering molten metal which comprises:

providing a reticulated, organic polymer foam;

impregnating said foam with an aqueous slurry of a thixotropic ceramic composition including a phosphate binder in an amount of at least 8%;

drying and heating said impregnated polymer foam to remove the organic component therefrom; and

firing at an elevated temperature of at least about 3020°

F. to volatilize the phosphate producing a substantially phosphate-free material and sintering the refractory to produce a material having individual grains of ceramic tightly coalesced to minimize porosity between the grains, wherein the porosity between the grains is microporosity and the microporosity is less than about 5%.

2. A process according to claim 1 wherein the polymer foam is a polyurethane foam.

3. A process according to claim 1 wherein the firing temperature is greater than or equal to 3020°

F. for from 15 minutes to 10 hours.

4. A process according to claim 3 wherein the firing temperature is greater than or equal to 3050°

F. for from 15 minutes to 10 hours.

5. A process according to claim 1 wherein said ceramic is alumina.

6. A process according to claim 1 wherein said phosphate is aluminum orthophosphate.