# US 2014/0190647 A1 · Investment Casting Refractory Material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190647 A1 - Document ID: US20140190647A1 - Status: Published application - Kind: A1 - Application number: 13/735,770 - Filed: 2013-01-07 - Published: 2014-07-10 - Earliest claimed: 2013-01-07 - Assignees: WiSys Technology Foundation, Inc. - Applicants: Wisys Technology Foundation, Inc. - Inventors: Daniel Scott McGuire; Eric Ernst Hellstrom - Web page: https://patentgrep.com/patent/US20140190647A1 ## CPC - B22C 1/02: characterised by additives for special purposes, e.g. indicators, breakdown additives - B22C 9/04: Use of lost patterns - B22C: FOUNDRY MOULDING (moulding refractory materials in general B28B) ## Abstract An investment casting method involves producing a casting shell by applying a hardenable refractory material to a sacrificial pattern. The casting shell having a plurality of phosphate bonds in the hardenable refractory material, which provide increased structural integrity during casting and improved frangibility during shell removal. The casting shell may also have a plurality of gaseous pockets suspended in the refractory material, which do not degrade the structural integrity during casting and provide improved frangibility during shell removal. ## Claims ### Claim 1 An investment casting method for creating an article from a sacrificial pattern, the method comprising: applying a liquid refractory material to an outer surface of an investment casting pattern; curing the liquid refractory material onto the outer surface of the pattern to from a shell, the curing process generating a plurality of phosphate bonds; replacing the pattern with a molten material; and allowing the molten material to solidify in the shell to produce the article. ### Claim 2 (depends on 1) The investment casting method of claim 1, wherein the liquid refractory material contains liquid phosphoric acid. ### Claim 3 (depends on 1) The investment casting method of claim 1, wherein the liquid refractory material contains a dibasic phosphate and a monobasic phosphate. ### Claim 4 (depends on 3) The investment casting method of claim 3, wherein the liquid refractory material contains greater than 1% by weight of dibasic ammonium phosphate and monobasic magnesium phosphate. ### Claim 5 (depends on 4) The investment casting method of claim 4, wherein the liquid refractory material contains greater than 5% by weight of dibasic ammonium phosphate and monobasic magnesium phosphate. ### Claim 6 (depends on 5) The investment casting method of claim 5, wherein the liquid refractory material contains greater than 1% by weight of the dibasic ammonium phosphate and greater than 7% by weight of monobasic magnesium phosphate. ### Claim 7 (depends on 5) The investment casting method of claim 5, wherein the liquid refractory material contains greater than 10% by weight of the dibasic ammonium phosphate and monobasic magnesium phosphate. ### Claim 8 (depends on 1) The investment casting method of claim 1, wherein the shell contains a plurality of ammonium phosphate bonds. ### Claim 9 (depends on 1) The investment casting method of claim 1, wherein the shell contains a plurality of magnesium phosphate bonds. ### Claim 10 (depends on 1) The investment casting method of claim 1, wherein the liquid refractory material is a foam having gaseous pockets suspended in a refractory material substrate. ### Claim 11 (depends on 10) The investment casting method of claim 10, wherein the liquid refractory material comprises no less than 40% by weight of the refractory material substrate. ### Claim 12 (depends on 10) The investment casting method of claim 10, wherein the outer surface of the gaseous pockets is alumina. ### Claim 13 (depends on 1) The investment casting method of claim 1, wherein the shell is formed of a single application of the liquid refractory material to the outer surface of the investment casting wax pattern. ### Claim 14 (depends on 1) The investment casting method of claim 1, further comprising the steps of heating the shell; and weakening the phosphate bonds in the shell to increase frangibility of the shell after the molten material has solidified in the shell to produce the article. ### Claim 15 An investment casting shell for the casting of high-temperature molten materials comprising: a hardened refractory material formed around an outer surface of an investment casting wax pattern to from a shell, the hardened refractory material deriving strength from a plurality of phosphate bonds. ### Claim 16 (depends on 15) The investment casting shell of claim 15, wherein the shell contains a plurality of ammonium phosphate bonds. ### Claim 17 (depends on 15) The investment casting shell of claim 15, wherein the shell contains a plurality of magnesium phosphate bonds. ### Claim 18 (depends on 15) The investment casting shell of claim 15, wherein the shell comprises less than 60% by weight of an entrapped gas. ### Claim 19 An investment casting refractory material for the casting of high-temperature molten materials comprising: a liquid refractory material containing dibasic ammonium phosphate and monobasic magnesium phosphate, and configured to be received on an outer surface of an investment casting wax pattern. ### Claim 20 (depends on 19) The investment casting refractory material of claim 19, wherein the liquid refractory material contains greater than 5% by weight of the dibasic ammonium phosphate and monobasic magnesium phosphate. ### Claim 21 (depends on 20) The investment casting refractory material of claim 20, wherein the liquid refractory material contains greater than 1% by weight of the dibasic ammonium phosphate and greater than 7% by weight of monobasic magnesium phosphate. ### Claim 22 (depends on 21) The investment casting refractory material of claim 21, wherein the liquid refractory material contains greater than 10% by weight of the dibasic ammonium phosphate and monobasic magnesium phosphate. ### Claim 23 (depends on 19) The investment casting refractory material of claim 19, wherein the liquid refractory material is a foam having gaseous pockets suspended in a refractory material substrate. ### Claim 24 (depends on 23) The investment casting refractory material of claim 23, wherein the liquid refractory material comprises less than 60% by weight of an entrapped gas.