# US 2020/0396805 A1 · Induction cookware with bi-metallic smart susceptor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0396805 A1 - Document ID: US20200396805A1 - Status: Published application - Kind: A1 - Application number: 16/442,415 - Filed: 2019-06-14 - Published: 2020-12-17 - Earliest claimed: 2019-06-14 - Assignees: The Boeing Company - Applicants: The Boeing Company - Inventors: Marc R. Matsen; Landon K. Henson - Web page: https://patentgrep.com/patent/US20200396805A1 ## CPC - H05B 6/1209: {induction cooking plates or the like and devices to be used in combination with them} - H05B 6/1245: {with special coil arrangements} - A47J 27/002: {Construction of cooking-vessels; Methods or processes of manufacturing specially adapted for cooking-vessels} - A47J 36/02: Selection of specific materials, e.g. heavy bottoms with copper inlay or with insulating inlay - H05B 6/062: {for cooking plates or the like} - H05B 2206/02: Induction heating - H05B 2206/023: using the curie point of the material in which heating current is being generated to control the heating temperature - H05B 2213/07: Heating plates with temperature control means - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - A47J: KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES ## Abstract Cookware, and an induction cooking system including the cookware, can include a container, a base layer, and a susceptor layer. The container and the base layer can be non-magnetic at room temperature, while the susceptor layer is magnetic at room temperature and has a Curie temperature at which the susceptor layer becomes non-magnetic. During heating of a material within the container, the base layer functions as a passive heat exchange to transfer heat across the susceptor layer, thereby decreasing a range of temperatures across the susceptor layer. Further, during the heating, the base layer conducts an electric current when the susceptor layer approaches a leveling temperature and/or the Curie temperature of the susceptor layer, thereby decreasing an amount of heat produced and resulting in a more even heating of the material. ## Claims ### Claim 1 A cookware for use with an induction coil, the cookware comprising: a container configured to receive a material to be heated; and a bi-metallic assembly over a surface of the container and in thermal communication with the container, wherein: the bi-metallic assembly comprises a susceptor layer and a base layer positioned adjacent to the susceptor layer; the susceptor layer is magnetic at room temperature and has a Curie temperature at which the susceptor layer is non-magnetic; the container is non-magnetic at the room temperature; and the base layer is non-magnetic at the room temperature, an electrical conductor, a thermal conductor, and in thermal communication with the susceptor layer. ### Claim 2 (depends on 1) The cookware of claim 1, wherein: the susceptor layer comprises nickel, iron, cobalt, or combinations thereof; the base layer comprises copper, bronze, non-magnetic copper-nickel, aluminum, or combinations thereof; and the container comprises glass, borosilicate glass, ceramic, non-magnetic metal, and combinations thereof. ### Claim 3 (depends on 1) The cookware of claim 1, wherein: the susceptor layer has a thickness of from 0.065 micrometers (μm) to 150 μm; and the base layer has a thickness of from 0.065 μm to 150 μm. ### Claim 4 (depends on 1) The cookware of claim 1, wherein the Curie temperature of the susceptor layer is from 30° C. to 500° C. ### Claim 5 (depends on 1) The cookware of claim 1, wherein: the susceptor layer is a metal alloy comprising from 30 weight percent (wt. %) to 36 wt. % nickel and from 63 wt. % to 70 wt. % iron; and the base layer comprises at least 65% copper. ### Claim 6 (depends on 1) The cookware of claim 1, wherein the base layer is positioned between the susceptor layer and the container. ### Claim 7 (depends on 1) The cookware of claim 1, wherein the susceptor layer is positioned between the base layer and the container. ### Claim 8 (depends on 1) The cookware of claim 1, wherein: the base layer has an electrical conductivity of from 1E7 Siemens per meter (S/m) to 6E7 S/m and a thermal conductivity of from 200 watts per meter-kelvin (W/m·K) to 400 W/m·K. ### Claim 9 A cookware for use with an induction coil, the cookware comprising: a container configured to receive a material to be heated, wherein the container comprises a susceptor material; and a base layer positioned adjacent to the container, wherein: the container is magnetic at a room temperature and has a Curie temperature at which the container is non-magnetic; and the base layer is non-magnetic at the room temperature, an electrical conductor, a thermal conductor, and in thermal communication with the container. ### Claim 10 An induction cooking system comprising: a cooktop comprising an induction coil configured to generate a electromagnetic field; and a cookware, comprising: a container configured to receive a material to be heated; and a bi-metallic assembly over a surface of the container and in thermal communication with the container, wherein: the bi-metallic assembly comprises a susceptor layer and a base layer positioned adjacent to the susceptor layer; the susceptor layer is magnetic at a room temperature and has a Curie temperature at which the susceptor layer is non-magnetic; the container is non-magnetic at the room temperature; and the base layer is non-magnetic at the room temperature, an electrical conductor, a thermal conductor, and in thermal communication with the susceptor layer. ### Claim 11 (depends on 10) The induction cooking system of claim 10, wherein: susceptor layer comprises nickel, iron, cobalt, or combinations thereof; the base layer comprises copper, bronze, non-magnetic copper-nickel, aluminum, or combinations thereof; and the container comprises glass, borosilicate glass, ceramic, non-magnetic metal, or combinations thereof. ### Claim 12 (depends on 10) The induction cooking system of claim 10, wherein: the susceptor layer has a thickness of from 0.065 micrometers (μm) to 150 μm; and the base layer has a thickness of from 0.065 μm to 150 μm. ### Claim 13 (depends on 10) The induction cooking system of claim 10, wherein the Curie temperature of the susceptor layer is from 100° C. to 500° C. ### Claim 14 (depends on 10) The induction cooking system of claim 10, wherein: the susceptor layer is a metal alloy comprising from 30 weight percent (wt. %) to 36 wt. % nickel and from 63 wt. % to 70 wt. % iron; and the base layer comprises at least 65% copper. ### Claim 15 A method for forming a cookware for use with an induction coil, the method comprising: forming a bi-metallic assembly comprising a susceptor layer and a base layer over a surface of a container, wherein: the container is configured to receive a material to be heated; the susceptor layer and the base layer are in thermal communication with the container; the susceptor layer is magnetic at a room temperature and has a Curie temperature at which the susceptor layer is non-magnetic; the base layer is non-magnetic at the room temperature, an electrical conductor, and a thermal conductor; and the container is non-magnetic at the room temperature. ### Claim 16 (depends on 15) The method of claim 15, further comprising: coating the surface of the container with the susceptor layer; and coating the susceptor layer with the base layer, wherein the susceptor layer is positioned between the container and the base layer. ### Claim 17 (depends on 15) The method of claim 15, further comprising: coating the surface of the container with the base layer; and coating the base layer with the susceptor layer, wherein the base layer is positioned between the container and the susceptor layer. ### Claim 18 (depends on 15) The method of claim 15, wherein the forming of the bi-metallic assembly over the surface of the container comprises: forming the susceptor layer to have a thickness of from 0.065 micrometers (μm) to 150 μm; and forming the base layer to have a thickness of from 0.065 μm to 150 μm. ### Claim 19 (depends on 15) The method of claim 15, wherein the Curie temperature of the susceptor layer is from 30° C. to 500° C. ### Claim 20 (depends on 15) The method of claim 15, wherein: the susceptor layer comprises nickel, iron, cobalt, and combinations thereof; the base layer comprises copper, bronze, non-magnetic copper-nickel, and combinations thereof; and the container comprises glass, borosilicate glass, ceramic, non-magnetic metal, and combinations thereof. ### Claim 21 (depends on 15) The method of claim 15, further comprising applying a nonstick coating to the container. ### Claim 22 A method for cooking, comprising: placing a material to be heated onto a cookware, the cookware comprising: a container configured to receive the material to be heated; and a bi-metallic assembly positioned over a surface of the container and in thermal communication with the container, the bi-metallic assembly comprising a base layer and a susceptor layer, wherein: the susceptor layer is magnetic at a room temperature and has a Curie temperature at which the susceptor layer is non-magnetic; the container is non-magnetic at the room temperature; and the base layer is non-magnetic at the room temperature, an electrical conductor, a thermal conductor, and in thermal communication with the susceptor layer; placing the cookware in proximity to an electromagnetic field; flowing, with the cookware in proximity to the electromagnetic field, an electric current through the susceptor layer and heating the susceptor layer toward a leveling temperature of the susceptor layer; transferring a flow of the electric current from the susceptor layer to the base layer thereby decreasing further heating of at least a portion of the susceptor layer and the container; and removing the material to be heated from the cookware.