Receptor device for inductive heating of aerosol-forming

Abstract

A susceptor device for inductively heating an aerosol-forming substrate, the susceptor device comprising: at least one susceptor body having a susceptor body surface, the at least one susceptor body comprising a first susceptor material; and a first thermal diffusion layer comprising a first thermal diffusion material, where the first thermal diffusion layer extends across at least a portion of the susceptor body surface in thermal contact or in thermal proximity to the portion of the susceptor body surface, and wherein the first thermal diffusion material has a thermal conductivity of at least 3.5 times, preferably 4 times, more preferably 5 times, of the thermal conductivity of the first susceptor material. The invention also relates to an inductively heatable aerosol-generating article comprising such a susceptor device.

Description

[0001] The present disclosure relates to a susceptor device for inductively heating an aerosol-forming substrate. The present invention also relates to an inductively heatable aerosol-generating article comprising such a susceptor device, and to an aerosol-generating device comprising such a susceptor device.

[0002] Aerosol-generating articles comprising at least one aerosol-forming substrate capable of forming an inhalable aerosol when heated are well known. To heat the aerosol-forming substrate, the aerosol-generating article can be received in an aerosol-generating device comprising an electric heater. The heater may be an induction heater comprising an induction source. The induction source is configured to generate an alternating magnetic field to inductively heat a susceptor device through at least one of eddy currents and hysteresis losses (depending on the electrical and magnetic properties of the susceptor device). The susceptor device may be an integral part of the aerosol-generating article and arranged so as to be in thermal proximity or direct physical contact with the aerosol-generating substrate to be heated. Alternatively, the susceptor device may be part of the aerosol-generating device. During operation of the device, volatile compounds are released from the heated aerosol-forming substrate in the aerosol-generating article and are entrained in the airflow drawn through the aerosol-generating article during puffing by the user. As the released compounds cool, they condense to form an aerosol.

[0003] However, depending on the geometry and internal structure of the susceptor device, the heating of the aerosol-generating substrate may sometimes be unsatisfactory. In particular, the heating of the substrate may be non-uniform, with different temperature regions across the substrate, leading to, for example, inefficient aerosol generation, inconsistent sensory perception of the aerosol, or the release of undesirable volatile compounds.

[0004] It would therefore be desirable to have a susceptor device which has the advantages of prior art solutions whilst alleviating the limitations of prior art solutions. In particular, it would be desirable to achieve more uniform heating of an aerosol-generating substrate.

[0005] According to one aspect of the present invention, a susceptor device for inductively heating an aerosol-forming substrate is provided. The susceptor device comprises: at least one susceptor body having a susceptor body surface, the susceptor body comprising a first susceptor material; and a first heat diffusion layer comprising a first heat diffusion material. The first heat diffusion layer extends across at least a portion of the susceptor body surface and is in thermal contact or proximity with the portion of the susceptor body surface. The first heat diffusion material also has a thermal conductivity that is at least 3.5 times, preferably 4 times, and more preferably 5 times, the thermal conductivity of the first susceptor material.

[0006] Using a susceptor arrangement including a heat diffusion layer provides several advantages compared to other susceptor arrangements.

[0007] The heat diffusion layer improves the distribution and dissipation of the generated heat across the surface of the susceptor device, thereby allowing a more uniform temperature distribution across the surface of the susceptor device while avoiding temperature hot spots on the surface of the susceptor device. Thus, the heating of the aerosol-generating substrate is improved and a uniform temperature distribution of the aerosol-generating substrate is achieved.

[0008] According to another aspect of the present invention, a susceptor device for inductively heating an aerosol-forming substrate is provided. The susceptor device comprises: at least one susceptor body having a susceptor body surface, the susceptor body comprising a first susceptor material; and a first heat diffusion layer comprising a first heat diffusion material. The first heat diffusion layer extends across at least a portion of the susceptor body surface and is in thermal contact or proximity with the portion of the susceptor body surface. The first susceptor material has a thermal conductivity greater than 25 W / (mK), particularly greater than 30 W / (mK), and more particularly greater than 40 W / (mK). For each of these values ​​of thermal conductivity of the first susceptor material, the first heat diffusion material may have a thermal conductivity that is at least 1.5 times, preferably 2 times, more preferably 2.5 times, and particularly 3 times the thermal conductivity of the first susceptor material.

[0009] Preferably, the first heat diffusion material may be a carbon allotrope, more preferably graphite or graphene. Carbon allotropes are known to exhibit high thermal conductivity values ​​and can be provided as very thin layers, thereby improving the thermal properties of the susceptor device without significantly increasing the volume and mass of the susceptor device.

[0010] Preferably, the first heat diffusion material may be provided as a graphite sheet, more preferably as a pyrolytic graphite sheet. Graphite sheets have the advantage of being flexible and amenable to cutting, and thus may be adapted and / or cut into different shapes for the susceptor device. The graphite sheet is preferably bonded to the susceptor body with a temperature-resistant adhesive, which is also harmless when the susceptor body is used to heat the aerosol-generating product.

[0011] Preferably, the graphite sheet may have a thickness of 1 micrometer to 200 micrometers, more preferably 5 micrometers to 20 micrometers, even more preferably substantially 10 micrometers.

[0012] Alternatively, the first heat diffusion material may be graphene. Thus, the graphene may be deposited onto the surface of the susceptor body via a vapor deposition method, preferably a chemical vapor deposition (CVD) method or a catalytic chemical vapor deposition (CCVD) method. When graphene is used, the first heat diffusion material may include one or more graphene layers.

[0013] In yet another alternative, the first heat diffusion material may be a metal. Preferably, the metal is selected from the group consisting of: copper, copper alloys, nickel, nickel alloys, aluminum and aluminum alloys.

[0014] Preferably, the first heat diffusion layer may have a thickness of 2 to 100 μm, more preferably 3 to 60 μm, even more preferably 5 to 20 μm, and particularly 12 to 16 μm. For example, the first heat diffusion layer may have a thickness of 3 to 30 μm or 30 to 60 μm.

[0015] Preferably, a spacer layer may be disposed between the susceptor body and the first thermal diffusion layer. The spacer layer may preferably include at least one of an electrically insulating layer, an anti-diffusion layer, a temperature-marking layer having a specific Curie temperature, and a protective layer. The spacer layer may be advantageous for providing additional functionality to the susceptor device. The electrically insulating layer may be advantageous for avoiding the "skin effect" in the susceptor device (i.e., the tendency of induced eddy currents at high frequencies to flow primarily at the outer surface of the susceptor). In particular, induced eddy currents tend to flow between the outer surface and a level known as the skin depth. By providing an electrically insulating layer between the susceptor body and the first thermal diffusion layer, the induced eddy currents can be confined to the susceptor body, where they can provide greater energy dissipation and, therefore, greater heat generation.

[0016] A temperature marking layer may be beneficial for determining whether the susceptor device has reached a predetermined temperature.

[0017] To this end, the temperature marker layer may include a temperature marker material that is magnetic (ferromagnetic or ferrimagnetic) and is selected to have a Curie temperature corresponding to the predefined temperature of the susceptor device. At the Curie temperature, the magnetic permeability of the temperature marker material decreases, causing its magnetic properties to change from ferromagnetic or ferrimagnetic to paramagnetic. This change in magnetic properties is accompanied by a temporary change in the electrical resistance of the temperature marker layer, and therefore also in the electrical resistance of the susceptor device. Thus, by monitoring the corresponding change in the current through the induction source used to heat the susceptor device, it is possible to detect when the temperature marker material has reached its Curie temperature, and therefore when the predefined temperature of the susceptor device has been reached.

[0018] A protective layer may be advantageous for providing corrosion protection. Thus, as used herein, the term "protective layer" describes a layer composed of or including a susceptor device for protecting underlying material(s) from corrosion. The corrosion-resistant material may be any suitable material that is resistant to corrosion. The corrosion-resistant material may include at least one of a corrosion-resistant metal, an inert metal, a corrosion-resistant alloy, a corrosion-resistant organic coating, glass, ceramic, a polymer, an anti-corrosion paint, a wax, or a grease.

[0019] An anti-diffusion layer can be advantageous for providing a barrier between the susceptor body and the first heat diffusion layer (e.g., preventing ion diffusion and unwanted potential buildup within the susceptor device). Therefore, as used herein, the term "anti-diffusion layer" describes a layer of a susceptor device composed of or including an anti-diffusion material that acts as a barrier to prevent diffusion of material from and / or into the underlying material(s) of the susceptor device. For example, the anti-diffusion layer can be configured to prevent metal migration from a material of the susceptor device into the aerosol-forming matrix, or to prevent metal migration between different layers of the susceptor device. For example, the anti-diffusion layer can have a thickness of 6 microns and can include or consist of nickel or a nickel alloy. This is particularly advantageous when using a metallic heat diffusion layer (e.g., copper or a copper alloy that can have a thickness between 12 and 16 microns) to prevent ions from the heat diffusion layer from diffusing into the susceptor body. In this example, the susceptor body can preferably include or consist of AISI 430 steel susceptor material and can be up to 60 microns thick.

[0020] On the side opposite to the susceptor device, the first thermal diffusion layer may additionally or alternatively be at least partially coated with at least one of an electrical insulation layer, an anti-diffusion layer, a temperature marking layer having a specific Curie temperature, and a protective layer. The electrical insulation layer, the anti-diffusion layer, the temperature marking layer, and the protective layer may have the same functions and properties as the corresponding layers described above with reference to the spacer layer.

[0021] Preferably, the susceptor body is a substantially flat element, and the susceptor body surface comprises a first susceptor body major surface and an opposing second susceptor body major surface. This has the advantage that the precursor of the susceptor body can be provided as a strip or sheet, and the susceptor body can be cut from the strip or sheet into the desired shape and size. Alternatively, the susceptor device precursor can be provided as a strip or sheet, and the susceptor device can be cut from the strip or sheet into the desired shape and size. Of course, the intermediate product of the susceptor device can also be provided as a strip-shaped or sheet-shaped precursor.

[0022] Preferably, the first heat diffusion layer may extend across at least a portion of at least one of the first susceptor body major surface and the second susceptor body major surface.

[0023] Alternatively, the first heat diffusion layer may extend across at least a portion of the first susceptor body major surface, and the susceptor arrangement may further comprise a second heat diffusion layer comprising a second heat diffusion material, wherein the second heat diffusion layer may extend across at least a portion of the second susceptor body major surface, being in thermal contact or proximity with that portion of the second susceptor body major surface. This is advantageous because at least a portion of both the first susceptor body major surface and the second susceptor body major surface are provided with the first heat diffusion layer and the second heat diffusion layer, respectively, thereby providing the benefits of heat diffusion layers on two opposing sides of the susceptor arrangement.

[0024] Preferably, the first heat diffusion layer extends across the entire first susceptor body major surface and / or the second heat diffusion layer extends across the entire second susceptor body major surface.

[0025] Preferably, the first heat diffusion layer and the second heat diffusion layer may be identical in at least one of the following characteristics: heat diffusion material, thickness of the heat diffusion layer, width of the heat diffusion layer, length of the heat diffusion layer, and area of ​​the heat diffusion layer.

[0026] As used herein, when the susceptor body is configured as a substantially flat element, the term "width" of the heat diffusion layer describes the dimension of the heat diffusion layer extending along a first axis of the heat diffusion layer. Similarly, the term "length" describes the dimension of the heat diffusion layer extending along a second axis of the heat diffusion layer that is perpendicular to the first axis. Finally, the term "area" describes the dimension of the surface of the heat diffusion layer extending along a given width and a given length.

[0027] Preferably, the susceptor body may be a multilayer susceptor body. The multilayer susceptor body may comprise at least two layers, in particular two layers, or three layers, or four layers.

[0028] The susceptor body may preferably include a layer made of a first susceptor material and a temperature-marking layer having a specific Curie temperature. The layer made of the first susceptor material and the temperature-marking layer may be adjacent layers. Additionally, the susceptor body may further include a protective layer. The protective layer may preferably be arranged on top of the temperature-marking layer, opposite the layer made of the first susceptor material. The layer made of the first susceptor material and the temperature-marking layer may be tightly coupled to each other. Similarly, if present, the protective layer and the temperature-marking layer may be tightly coupled to each other. For example, one of the respective layers may be plated, deposited, coated, clad, or welded to the respective other layer. Similarly, one of the respective layers may be applied to the respective other layer by spraying, dipping, rolling, electroplating, or cladding. Any of the above-described configurations falls within the term "tightly coupled" as used herein.

[0029] In an alternative configuration, the susceptor body may be strip-shaped, wherein the susceptor body surface is the shell surface of the strip-shaped susceptor body. Regarding configurations in which the susceptor body is provided as a substantially flat element, the precursor of the strip-shaped susceptor body may be provided as a filament or strip, and the strip-shaped subsequent body may be cut from the filament or strip to the desired size. Of course, the susceptor device or its intermediate product may similarly be provided as a filament-shaped or strip-shaped precursor and processed accordingly.

[0030] The susceptor body can also include at least one fiber or thread, and more preferably, the susceptor body or susceptor device can be configured as one of a core, fluff, net or fabric. When the aerosol-forming substrate is configured as a liquid matrix or a gel-like matrix, these alternative configurations are particularly advantageous, wherein the susceptor body or susceptor device configured as one of a core, fluff, net or fabric can not only be used to heat the aerosol-forming substrate, but also store and / or transport the aerosol-forming substrate due to the capillary properties of the core, fluff, net or fabric. The susceptor body can be configured as a fiber, a fiber bundle or a thread, and then the first heat diffusion layer can be provided to the susceptor body, and then the core, fluff, net or fabric can be manufactured by the susceptor body including the first heat diffusion layer. Alternatively, the susceptor body has been configured as one of a core, fluff, net or fabric, and then the first heat diffusion layer can be provided to the susceptor body. Intermediate forms are also possible. For example, a fiber is provided, which includes a first susceptor material, a temperature marker layer with a specific Curie temperature, and a protective layer. The fibers may then be used to make a susceptor body web, and the first heat diffusion layer may then be provided to the susceptor body web.

[0031] Alternatively, the susceptor body or susceptor device may be a mesh. Unlike the above configuration, in this preferred configuration, the susceptor body does not include fibers or threads, but is instead formed entirely as a mesh. For example, the susceptor body may be provided as a multi-layer sheet material, which is then perforated to form a mesh, and the heat diffusion layer may then be applied to the mesh. Alternatively, the susceptor device may be provided as a multi-layer sheet material, which is then perforated to form a mesh.

[0032] Preferably, the susceptor body may be a bead, and the susceptor body surface is the outer surface of the bead. Thus, the susceptor body may be provided as a block of material having a particular spherical shape. An advantage of the susceptor body being a bead is that the susceptor means may be diffused or dispersed within the aerosol-forming substrate, thereby providing more uniform heating of the aerosol-forming substrate compared to an arrangement having a substantially flat or strip-shaped susceptor means.

[0033] Preferably, the first heat diffusion material and / or the second heat diffusion material may have a thermal conductivity greater than 80 W / (m K), in particular greater than 100 W / (m K), more particularly greater than 200 W / (m K), preferably greater than 350 W / (m K), more preferably greater than 1000 W / (m K) at 25 degrees Celsius.

[0034] According to another aspect of the present invention, there is provided an inductively heatable aerosol-generating article comprising an aerosol-forming substrate and at least one susceptor device as described herein. All preferred configurations and advantages associated with those preferred configurations described above may be correspondingly applied to the inductively heatable aerosol-generating article.

[0035] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming substrate capable of releasing volatile compounds that can form an aerosol when heated. Preferably, the aerosol-generating article is a heated aerosol-generating article. That is, an aerosol-generating article comprising at least one aerosol-forming substrate that is intended to be heated rather than burned. The aerosol-generating article may be a consumable product, in particular a consumable product that is discarded after a single use. For example, the article may be a cartridge comprising a liquid aerosol-forming substrate to be heated. As another example, the article may be a rod-shaped article, in particular a tobacco product, similar to a traditional cigarette.

[0036] As used herein, the term "aerosol-forming substrate" means a substrate formed by or comprising an aerosol-forming material that can release volatile compounds when heated to generate an aerosol. Preferably, the aerosol-forming substrate is intended to be heated rather than burned to release the volatile compounds that form an aerosol. The aerosol-forming substrate can be a solid aerosol-forming substrate, a liquid aerosol-forming substrate, a gel-like aerosol-forming substrate, or any combination thereof. For example, the aerosol-forming substrate can include both a solid component and a liquid component. The aerosol-forming substrate can include a tobacco-containing material that contains volatile tobacco flavor compounds released from the substrate when heated. Alternatively or in addition, the aerosol-forming substrate can include a non-tobacco material. The aerosol-forming substrate can also include an aerosol-forming agent. The example of a suitable aerosol-forming agent is glycerol and propylene glycol. The aerosol-forming substrate can also include other additives and ingredients, such as nicotine or spices. The aerosol-forming substrate may also be a paste-like material, a pouch of porous material comprising an aerosol-forming substrate, or for example loose tobacco mixed with a gelling agent or binder, which may include common aerosol formers such as glycerol, and compressed or moulded into a rod.

[0037] Preferably, the article may be an elongated article or a rod-shaped article. The elongated or rod-shaped article may have a shape similar to that of a conventional cigarette.

[0038] The aerosol-generating article, in particular an elongated or strip-shaped article, may have a circular, elliptical, oval, square, rectangular, triangular or polygonal cross-section.

[0039] For example, the aerosol-generating article may be a rod-shaped article, in particular a cylindrical article, comprising one or more of the following elements: a distal front-rod element, a matrix element, a first tube element, a second tube element and a filter element.

[0040] The substrate element preferably comprises at least one aerosol-forming substrate to be heated and a susceptor arrangement in thermal contact or thermal proximity to the aerosol-forming substrate.The substrate element may have a length of 10 mm to 14 mm, for example 12 mm.

[0041] The first tubular element is more distal than the second tubular element. Preferably, the first tubular element is proximal to the matrix element, while the second tubular element is proximal to the first tubular element and distal to the filter element, i.e., between the first tubular element and the filter element. At least one of the first tubular element and the second tubular element may include a central air passage. The cross-section of the central air passage of the second tubular element may be larger than the cross-section of the central air passage of the first tubular element. Preferably, at least one of the first tubular element and the second tubular element may include a hollow cellulose acetate tube. At least one of the first tubular element and the second tubular element may have a length of 6 to 10 mm, for example, 8 mm.

[0042] The filter element is preferably used as a mouthpiece, or as part of a mouthpiece together with the second tube element. As used herein, the term "mouthpiece" refers to the portion of the article through which the aerosol leaves the aerosol-generating article. The filter element may have a length of 10 mm to 14 mm, for example 12 mm.

[0043] The distal front rod element can be used to cover and protect the distal front end of the matrix element. The distal front rod element can have a length of 3 mm to 6 mm, for example 5 mm. The distal front rod element can be made of the same material as the filter element.

[0044] All aforementioned elements can be arranged in sequence along the length axis of goods according to the above-mentioned order, wherein the distal front rod element is preferably arranged at the distal end of goods, and the filter element is preferably arranged at the proximal end of goods. Each element in the aforementioned elements can be substantially cylindrical. Especially, all elements can have identical external cross-sectional shape and / or size. In addition, these elements can be limited by one or more outer packagings, so that these elements are kept together and maintain the desired cross-sectional shape of strip-shaped goods. Preferably, the packaging is made of paper. The packaging can also include an adhesive that the overlapping free ends of the packaging are adhered to each other. For example, the distal front rod element, matrix element and the first tube element can be limited by the first packaging, and the second tube element and the filter element can be limited by the second packaging. The second packaging can also limit at least a portion of the first tube element (after being wrapped by the first packaging) so that the distal front rod element, matrix element and the first tube element defined by the first packaging are connected to the second tube element and the filter element. The second packaging can include the perforation around its circumference.

[0045] According to another aspect of the present invention, there is provided an aerosol-generating device for heating an aerosol-generating article comprising an aerosol-forming substrate, the aerosol-generating device comprising at least one susceptor device as described herein. All preferred configurations and advantages associated with those preferred configurations described above may apply accordingly to the aerosol-generating device.

[0046] As used herein, the term "aerosol-generating device" may describe an electrically operated device for interacting with an aerosol-generating article comprising an aerosol-forming substrate to generate an aerosol by inductively heating the aerosol-forming substrate via a susceptor arrangement of the device. Preferably, the aerosol-generating device is a puffing device for generating an aerosol that can be inhaled directly by a user through the user's mouth. In particular, the aerosol-generating device is a handheld aerosol-generating device.

[0047] The device may comprise a receiving cavity for removably receiving at least a portion of the aerosol-generating article.

[0048] The aerosol generating device comprises an induction heating device configured and arranged to generate an alternating magnetic field capable of inductively heating a susceptor means of the device.

[0049] To generate the alternating magnetic field, the induction heating device may comprise at least one induction coil surrounding at least a portion of the susceptor device. The at least one induction coil may be a spiral coil or a flat planar coil, in particular a pancake coil or a bent planar coil.

[0050] The induction heating device may further comprise an alternating current (AC) generator. The AC generator may be powered by the power supply of the aerosol generating device. The AC generator may be operably coupled to the at least one induction coil. In particular, the at least one induction coil may be an integral part of the AC generator. The AC generator is configured to generate a high-frequency oscillating current through the at least one induction coil for generating an alternating magnetic field. The AC current may be supplied continuously to the at least one induction coil after activation of the system, or may be supplied intermittently, for example on a puff-by-puff basis. Preferably, the induction heating device comprises a DC / AC converter comprising an LC network, wherein the LC network comprises a series connection of a capacitor and an inductor. The DC / AC converter may be connected to a DC power supply.

[0051] The induction heating device is preferably configured to generate a high-frequency magnetic field. As mentioned herein, the high-frequency magnetic field can be an alternating magnetic field with a frequency in the range of 500kHz (kilohertz) to 30MHz (megahertz), in particular in the range of 5MHz (megahertz) to 15MHz (megahertz), preferably in the range of 5MHz (megahertz) to 10MHz (megahertz).

[0052] The aerosol-generating device may further comprise a controller configured to control the operation of the heating process, in particular for controlling the heating of the aerosol-forming liquid to a predetermined operating temperature, preferably in a closed-loop configuration.

[0053] The controller may be the overall controller of the aerosol generating device, or may be part of the overall controller.

[0054] The controller may include a microprocessor, such as a programmable microprocessor, a microcontroller, or an application-specific integrated circuit (ASIC), or other electronic circuitry capable of providing control. The controller may include additional electronic components, such as at least one DC / AC inverter and / or a power amplifier, such as a class C power amplifier, a class D power amplifier, or a class E power amplifier. In particular, the inductive source may be part of the controller.

[0055] The aerosol generating device may further comprise a power supply, in particular a DC power supply, configured to provide a DC supply voltage and a DC supply current to the induction source.

[0056] Preferably, the power source is a battery, such as a lithium iron phosphate battery. The power source may be rechargeable. The power source may have a capacity to store sufficient energy for one or more user experiences. For example, the power source may have sufficient capacity to allow continuous aerosol generation for approximately six minutes, or multiples of six minutes. In another example, the power source may have sufficient capacity to allow a predetermined number of puffs or discontinuous activation of the induction source.

[0057] The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0058] Example Ex1: A susceptor device for inductively heating an aerosol-forming substrate, the susceptor device comprising: at least one susceptor body having a susceptor body surface, the susceptor body comprising a first susceptor material; and a first heat diffusion layer comprising a first heat diffusion material, wherein the first heat diffusion layer extends across at least a portion of the susceptor body surface and is in thermal contact or thermal proximity with the portion of the susceptor body surface, and wherein the first heat diffusion material has a thermal conductivity that is at least 3.5 times, preferably 4 times, more preferably 5 times the thermal conductivity of the first susceptor material.

[0059] Example Ex2: The susceptor device according to example Ex1, wherein the first heat diffusion material is a carbon allotrope, preferably graphite or graphene.

[0060] Example Ex3: The susceptor device according to example Ex1 or Ex2, wherein the first heat diffusion material is provided as a graphite sheet, preferably a pyrolytic graphite sheet.

[0061] Example Ex4: A susceptor device according to Example Ex3, wherein the graphene sheet has a thickness of 1 to 200 micrometers, preferably 5 to 20 micrometers, more preferably substantially 10 micrometers.

[0062] Example Ex5: The susceptor device according to example Ex1, wherein the first heat diffusion material is a metal.

[0063] Example Ex6: The susceptor device according to example Ex5, wherein the metal is selected from the group consisting of: copper, copper alloys, nickel, nickel alloys, aluminum, and aluminum alloys.

[0064] Example Ex7: The susceptor device according to example Ex5 or Ex6, wherein the first heat diffusion layer has a thickness of 2 to 100 μm, preferably 3 to 60 μm, more preferably 5 to 20 μm, more preferably 12 to 16 μm, for example 3 to 30 μm or 30 to 60 μm.

[0065] Example Ex8: The susceptor device according to any one of the preceding examples Ex1 to Ex7, wherein a spacer layer is disposed between the susceptor body and the first heat diffusion layer.

[0066] Example Ex9: The susceptor device of Example Ex8, wherein the separator layer comprises at least one of an electrical insulating layer, an anti-diffusion layer, a temperature marking layer having a specific Curie temperature, and a protective layer.

[0067] Example Ex10: The susceptor device according to any of the preceding examples Ex1 to Ex9, wherein the first heat diffusion layer is at least partially coated with at least one of an electrical insulation layer, an anti-diffusion layer, a temperature marking layer having a specific Curie temperature, and a protective layer.

[0068] Example Ex11: The susceptor device according to any of the preceding examples Ex1 to Ex10, wherein the susceptor body is a substantially flat element, and the susceptor body surface comprises a first susceptor body major surface and an opposing second susceptor body major surface.

[0069] Example Ex12: The susceptor device according to example Ex11, wherein the first heat diffusion layer extends across at least a portion of at least one of the first susceptor body major surface and the second susceptor body major surface.

[0070] Example Ex13: The susceptor device of Example Ex11, wherein the first heat diffusion layer extends across at least a portion of the first susceptor body major surface, the susceptor device further comprising a second heat diffusion layer, the second heat diffusion layer comprising a second heat diffusion material, wherein the second heat diffusion layer extends across at least a portion of the second susceptor body major surface and is in thermal contact or thermal proximity with the portion of the second susceptor body major surface.

[0071] Example Ex14: The susceptor device according to example Ex13, wherein the first heat diffusion layer extends across the entire first susceptor body major surface and / or the second heat diffusion layer extends across the entire second susceptor body major surface.

[0072] Example Ex15: The susceptor device according to example Ex13 or Ex14, wherein the first heat diffusion layer and the second heat diffusion layer are identical in at least one of the following properties: heat diffusion material, thickness of the heat diffusion layer, width of the heat diffusion layer, length of the heat diffusion layer, and area of ​​the heat diffusion layer.

[0073] Example Ex16: The susceptor device according to any one of Examples Ex11 to Ex15, wherein the susceptor body is a multi-layer susceptor body.

[0074] Example Ex17: The susceptor device according to example Ex16, wherein the susceptor body comprises at least two layers.

[0075] Example Ex18: The susceptor device according to example Ex17, wherein the susceptor body comprises a layer made of the first susceptor material and a temperature marking layer having a specific Curie temperature.

[0076] Example Ex19: The susceptor device according to example Ex18, wherein the susceptor body further comprises a protective layer, the protective layer preferably being tightly coupled to the temperature marking layer.

[0077] Example Ex20: The susceptor device according to any one of Examples Ex1 to Ex10, wherein the susceptor body is strip-shaped, and the susceptor body surface is a shell surface of the strip-shaped susceptor body.

[0078] Example Ex21: The susceptor device according to any one of Examples Ex1 to Ex10, wherein the susceptor body comprises at least one fiber or thread.

[0079] Example Ex22: The susceptor device according to example Ex21, wherein the susceptor body or the susceptor device is provided as one of a core, a fleece, a mesh, or a fabric.

[0080] Example Ex23: The susceptor device according to any one of examples Ex1 to Ex10, wherein the susceptor body or the susceptor device is a mesh.

[0081] Example Ex24: The susceptor device according to any one of Examples Ex1 to Ex10, wherein the susceptor body is a bead and the susceptor body surface is the bead outer surface.

[0082] Example Ex25: The susceptor device according to any of Examples Ex1 to Ex24, wherein the first heat diffusing material and / or the second heat diffusing material has a thermal conductivity greater than 80 W / (mK), in particular greater than 100 W / (mK), more particularly greater than 200 W / (mK), preferably greater than 350 W / (mK), more preferably greater than 1000 W / (mK).

[0083] Example Ex26: An inductively heatable aerosol-generating article comprising an aerosol-forming substrate and at least one susceptor device according to any one of Examples Ex1 to Ex25.

[0084] Example Ex27: An aerosol-generating device for heating an aerosol-generating article comprising an aerosol-forming substrate, the aerosol-generating device comprising at least one susceptor device according to any one of Examples Ex1 to Ex25.

[0085] Several examples will now be further described with reference to the accompanying drawings, in which:

[0086] Figure 1 A schematically shows a possible configuration of the susceptor body without a heat diffusion layer;

[0087] Figure 1BC schematically shows a possible configuration of the susceptor body and the heat diffusion layer according to the present invention;

[0088] Figure 2 A schematically shows a possible configuration of the susceptor body without a heat diffusion layer;

[0089] Figure 2 BC schematically shows different possible layer configurations of a susceptor device according to the present invention;

[0090] Figure 3 AB shows in schematic cross-sectional views further possible layer configurations of the susceptor device according to the invention;

[0091] Figure 4 shows a schematic diagram of a cross section through a strip-shaped susceptor device according to the present invention;

[0092] Figure 5 schematically illustrates an inductively heatable aerosol-generating article comprising a susceptor arrangement according to the present invention;

[0093] Figure 6 schematically illustrates an aerosol-generating device including an aerosol-generating article according to the present invention;

[0094] Figure 7 schematically illustrates an aerosol generating device comprising a susceptor device according to the present invention; and

[0095] Figure 8 Another embodiment of an aerosol generating device comprising a susceptor device according to the invention is schematically shown.

[0096] exist Figure 1 In A, a susceptor body 2 is shown which is arranged as a substantially flat element. The susceptor body 2 has a susceptor body surface 3, wherein Figure 1 In the configuration shown in A, the susceptor body surface 3 includes a first susceptor body major surface 3' and a second susceptor body major surface 3" opposite the first susceptor body major surface 3'.

[0097] exist Figure 1 B shows the Figure 1 A susceptor arrangement of a susceptor body 2 and a first heat diffusion layer 4 is shown. The first heat diffusion layer 4 is in thermal contact or thermal proximity with a first susceptor body major surface 3' and extends substantially across the entire first susceptor body major surface 3'. In contrast, a second susceptor body major surface 3" opposite the first susceptor body major surface 3' is not covered by any layer (in particular the heat diffusion layer) but is exposed.

[0098] exist Figure 1In Figure C, the susceptor device 1 includes a first heat diffusion layer 4 and a second heat diffusion layer 5. The first heat diffusion layer 4 is in thermal contact or thermal proximity with the first susceptor body major surface 3' and extends across substantially the entire first susceptor body major surface 3', wherein the second heat diffusion layer 5 is in thermal contact or thermal proximity with the second susceptor body major surface 3" and extends across substantially the entire second susceptor body major surface 3". The first heat diffusion layer 4 and / or the second heat diffusion layer 5 improve the distribution and dissipation of generated heat across the surface of the susceptor device 1, thereby allowing for a more uniform temperature distribution across the surface of the susceptor device 1 while avoiding temperature hot spots on the surface of the susceptor device 1. Consequently, heating of the aerosol-generating substrate is improved, and a uniform temperature distribution of the aerosol-generating substrate is achieved.

[0099] exist Figure 2 In Figure A, another possible configuration of the susceptor body 2 is depicted in cross-section. The susceptor body 2 is a multilayer susceptor body comprising a layer made of a first susceptor material 6, said layer being tightly coupled to a temperature marker layer 7. The susceptor body 2 also comprises a protective layer 8, which is tightly coupled to the temperature marker layer 7 opposite the layer made of the first susceptor material 6. The first susceptor body major surface 3' is the outer surface of the layer made of the first susceptor material 6, while the second susceptor body major surface 3" is the outer surface of the protective layer 8. The first susceptor material 6 is steel, in particular AISI 430 steel, and has a thickness of 40.5 microns. The temperature marker layer 7 is made of FeNi80Mo alloy and has a thickness of 16.5 microns. The protective layer 8 is made of steel, in particular AISI 430 steel, and has a thickness of 3 microns. In an alternative configuration, the temperature marker layer 7 is made of FeNi80Mo alloy and has a thickness of 16 microns, while the protective layer 8 is made of steel, in particular AISI 430 steel, and has a thickness of 3.5 microns.

[0100] Figure 2 B and 2C show another possible configuration of the susceptor device 1. For simplicity only, the susceptor body 2 is shown with Figure 2 The first susceptor body main surface 3' and the second susceptor body main surface 3" are respectively provided with a first heat diffusion layer 4 and a second heat diffusion layer 5. The first heat diffusion layer 4 and the second heat diffusion layer 5 respectively include a first heat diffusion material and a second heat diffusion material.

[0101] exist Figure 2 In the configuration of C, the first heat diffusion layer 4 and the second heat diffusion layer 5 are in thermal contact with the susceptor body 2, while Figure 2In the configuration of FIG. 2 , a spacer layer 9 is placed between the susceptor body 2 and the first heat diffusion layer 4 and between the susceptor body 2 and the second heat diffusion layer 5, respectively. Each of the two spacer layers 9 is an electrical insulator layer having a thickness of 5 microns. The first heat diffusion material and / or the second heat diffusion material may be a carbon allotrope, such as graphite. The first heat diffusion layer 4 and the second heat diffusion layer 5 may each have a thickness of 10 microns. The graphite is preferably provided as a graphite sheet and bonded to a substrate such as a heat dissipation film by means of an adhesive. Figure 2 The receptor body 2 shown in C, or combined with Figure 2 The corresponding separator layer 9 is shown in B.

[0102] Alternatively, the first heat diffusion material and / or the second heat diffusion material may be another carbon allotrope, such as graphene. Graphene may be deposited onto the substrate by a vapor deposition method (preferably a chemical vapor deposition (CVD) method or a catalytic chemical vapor deposition (CCVD) method). Figure 2 C, or deposited onto the susceptor body 2 as shown in FIG. Figure 2 On the separation layer 9 shown in B. The first heat diffusion layer 4 and / or the second heat diffusion layer 5 may each include one graphene layer or several graphene layers.

[0103] In another alternative configuration, the first heat spreading material and / or the second heat spreading material is a metal or a metal alloy.

[0104] Figure 3 Another possible configuration of the susceptor device 1 is shown in A. The susceptor device 1 comprises a susceptor body 2 comprising a first susceptor material 6 having a first susceptor body major surface 3′ and a second susceptor body major surface 3″. The first susceptor material 6 is steel, in particular AISI 430 steel. The susceptor body 2 may have a thickness of up to 60 microns. The first heat diffusion layer 4 is in thermal contact with the first susceptor body major surface 3′ and has a thickness between 12 and 16 microns. As described above, the first heat diffusion layer 4 is tightly coupled to the susceptor body 2 and comprises at least a first heat diffusion material, preferably a carbon allotrope or a metal. Alternatively, as Figure 3 As shown in FIG. 2B , a spacer layer 9 is disposed between the susceptor body 2 and the first thermal diffusion layer 4. The spacer layer 9 is made of an anti-diffusion material and has a thickness of 6 microns. The susceptor assembly 1 also includes a temperature marker layer 7, which is tightly coupled to the first thermal diffusion layer 4 opposite the susceptor body 2. The temperature marker layer 7 is made of an FeNi80Mo alloy and has a thickness between 6 and 8 microns. Furthermore, the susceptor assembly 1 includes a protective layer 8 tightly coupled to the temperature marker layer 7. The protective layer 8 is made of steel, particularly AISI 430 steel, and has a thickness of 3.5 microns.

[0105] Figure 4 A cross section through a strip-shaped susceptor device 1 is schematically shown. The strip-shaped susceptor device 1 comprises a multi-layer strip-shaped susceptor body 2 having a susceptor body surface 3, which is the shell surface of the strip-shaped susceptor body 2. The multi-layer strip-shaped susceptor body 2 comprises a core comprising a first susceptor material 6. On top, the strip-shaped susceptor body 2 further comprises a temperature marking layer 7, which is tightly coupled to the core comprising the first susceptor material 6. On top of the temperature marking layer 7, the strip-shaped susceptor body 2 further comprises a protective layer 8, which is tightly coupled to the temperature marking layer 7. Furthermore, the susceptor device 1 comprises a first heat diffusion layer 4, which is tightly coupled to the susceptor body 2 and, in this configuration, to the protective layer 8 of the susceptor body 2, which forms the susceptor body surface 3.

[0106] It should be self-evident that the above configuration in the case of a strip-shaped susceptor device 1 is purely exemplary and that other configurations provided as a substantially flat element as explained above with respect to the susceptor body 2 may be implemented.

[0107] Figure 5 An inductively heatable aerosol-generating article 10 comprising a susceptor device 1 according to the present invention is schematically shown (not to scale). The aerosol-generating article 10 is a substantially strip-shaped consumable comprising five elements arranged sequentially in coaxial alignment: a distal front-rod element 11, a substrate element 12, a first tube element 13, a second tube element 14, and a filter element 15. The distal front-rod element 11 is arranged at the distal end 16 of the aerosol-generating article 10 to cover and protect the distal front end of the substrate element 12, while the filter element 15 is arranged at the proximal end 17 of the aerosol-generating article 10. Both the distal front-rod element 11 and the filter element 15 may be made of the same filter material. The filter element 15 preferably serves as a mouthpiece, preferably as part of a mouthpiece together with the second tube element 14.

[0108] The filter element 15 may have a length of 10 mm to 14 mm, for example 12 mm, and the distal front rod element 11 may have a length of 3 mm to 6 mm, for example 5 mm. The substrate element 12 comprises an aerosol-forming substrate 18 to be heated and a susceptor device 1 according to the invention (e.g. Figure 11B, 1C; 2B, 2C, 3A, or 3B), the susceptor device is configured and arranged to heat the aerosol-forming substrate 18. To this end, the susceptor device 1 is fully embedded in the aerosol-forming substrate 18 so as to be in direct thermal contact with the aerosol-forming substrate 18. The substrate element 12 may have a length of 10 to 14 mm, for example, 12 mm. Each of the first tube element 13 and the second tube element 14 is a hollow cellulose acetate tube having a central air passage 19, 20, wherein the cross-section of the central air passage 20 of the second tube element 14 is larger than the cross-section of the central air passage 19 of the first tube element 13. The first tube element 13 and the second tube element 14 may have a length of 6 to 10 mm, for example, 8 mm.

[0109] In use, an aerosol formed by the volatile compounds released from the substrate element 12 upon heating is drawn through the first and second tube elements 13, 14 and the filter element 15 towards the proximal end 17 of the aerosol-generating article 10. Each of the aforementioned elements 11, 12, 13, 14, 15 may be substantially cylindrical. In particular, all elements 11, 12, 13, 14, 15 may have the same external cross-sectional shape and size.

[0110] In addition, these elements can be limited by one or more outer packagings, so that these elements are kept together and maintain the desired cross-sectional shape of strip-shaped product. Distal front rod element 11, matrix element 12 and first tube element 13 are limited by first packaging 21, and second tube element 14 and filter element 15 are limited by second packaging 22 simultaneously. Second packaging 22 also limits at least a portion of first tube element 13 (after being wrapped by first packaging 21), so that distal front rod element 11, matrix element 12 and first tube element 13 limited by first packaging 21 are connected to second tube element 14 and filter element 15. Preferably, first packaging 21 and second packaging 22 are made of paper. In addition, second packaging 22 can comprise the perforation (not shown) around its circumference. Packer 21,22 can also comprise the adhesive that the overlapping free ends of packer are adhered to each other.

[0111] like Figure 6 As shown in Figure 5The aerosol-generating article 10 is configured for use with an induction-heated aerosol-generating device 23. The aerosol-generating device 23 and the aerosol-generating article 10 together form an aerosol-generating system 24. The aerosol-generating device 23 comprises a cylindrical receiving cavity 25 defined within a proximal portion 26 of the aerosol-generating device 23 for receiving at least a distal portion of the aerosol-generating article 10 therein. The aerosol-generating device 23 further comprises an induction heating device comprising an induction coil 27 for generating an alternating magnetic field, in particular a high-frequency magnetic field, within the cylindrical receiving cavity 25. The induction coil 27 is a helical coil circumferentially surrounding the cylindrical receiving cavity 25. The induction coil 27 is arranged such that when the aerosol-generating article 10 is inserted into the cylindrical receiving cavity 25 of the aerosol-generating device 23, the susceptor device 1 of the aerosol-generating article 10 is exposed to the magnetic field. Thus, when the induction heating means is activated, the susceptor means 1 heats up due to eddy currents and / or hysteresis losses induced by the alternating magnetic field (depending on the magnetic and electrical properties of the susceptor material of the susceptor means 1). The susceptor means 1 is heated until an operating temperature is reached that is sufficient to vaporize the aerosol-forming substrate 18 surrounding the susceptor means 1 within the aerosol-generating article 10. Within the distal portion 28, the aerosol-generating device 23 further comprises a DC power supply 29 and a controller 30 (at Figure 6 In addition to the induction coil 27, the induction heating device is preferably at least partially an integrated part of the controller 30.

[0112] Figure 7 An aerosol generating device 23' comprising a susceptor device 1 according to the present invention is shown. The aerosol generating device 23' is configured for use with an aerosol generating article 10'. The aerosol generating article 10' is configured substantially similarly to Figure 5 ', but lacks the receptor device 1. The aerosol generating device 23' and the aerosol generating article 10' together form an aerosol generating system 24'. The aerosol generating device 23' comprises a cylindrical receiving cavity 25', which is defined within a proximal portion 26' of the aerosol generating device 23' for receiving at least a distal portion of the aerosol generating article 10' therein. The aerosol generating device 23' further comprises an induction heating device, which comprises an induction coil 27' for generating an alternating magnetic field, in particular a high-frequency magnetic field, within the cylindrical receiving cavity 25'. The induction coil 27' is a spiral coil circumferentially surrounding the cylindrical receiving cavity 25'. The receptor device 1 is arranged as a substantially cylindrical hollow body within and coaxial with the cylindrical receiving cavity 25'. In this configuration, the receptor device 1 realizes an induction heating furnace or heating chamber. As Figure 7As shown in , the susceptor device 1 is arranged such that when the aerosol-generating article 10 ′ is inserted into the cylindrical receiving cavity 25 ′, the susceptor device at least partially surrounds the substrate element 12 of the aerosol-generating article 10 ′.

[0113] The susceptor device 1 is also arranged so that it is exposed to a magnetic field generated by the induction heating device of the aerosol generating device 23'. Thus, when the induction heating device is activated, the susceptor device 1 heats up due to eddy currents and / or hysteresis losses (depending on the magnetic and electrical properties of the susceptor material of the susceptor device 1) induced by the alternating magnetic field. The susceptor device 1 is heated until it reaches an operating temperature sufficient to vaporize the aerosol-forming substrate 18 within the aerosol-generating article 10'. Within the distal portion 28', the aerosol generating device 23' further comprises a DC power supply 29' and a controller 30' (at Figure 7 In addition to the induction coil 27 ', the induction heating device is preferably at least partially an integrated part of the controller 30 '.

[0114] Figure 8 Another embodiment of an aerosol generating device 23" comprising a susceptor device 1 according to the present invention is shown. The aerosol generating device 23" is configured for use with an aerosol generating article 10". The aerosol generating article 10" is substantially similar to Figure 5 The aerosol-generating article 10 is configured as shown in , but lacks the susceptor means 1 and the distal front-rod element 11. Instead, the substrate element 12 has a greater length extension.

[0115] The aerosol generating device 23″ comprises a cylindrical receiving cavity 25″ defined within a proximal portion 26″ of the aerosol generating device 23″ for receiving at least a distal portion of the aerosol generating article 10″ therein. The aerosol generating device 23″ further comprises an induction heating device comprising an induction coil 27″ for generating an alternating magnetic field, in particular a high-frequency magnetic field, within the cylindrical receiving cavity 25″. The induction coil 27″ is a spiral coil circumferentially surrounding the cylindrical receiving cavity 25″. The susceptor device 1 is configured as a sheet element, a strip element or a pin element and is arranged within the cylindrical receiving cavity 25″.

[0116] The distal end of the susceptor means 1 is arranged at the bottom portion of the cylindrical receiving cavity 25". From there, the susceptor means 1 extends into the inner space of the cylindrical receiving cavity 25" towards the opening of the cylindrical receiving cavity 25" at the proximal portion 26" of the aerosol generating device 23". Figure 8As shown in the figure, the proximal end of the sensor device 1 can be tapered, pointed or provided with a sharp edge to easily penetrate into the substrate element 12 of the aerosol-generating article 10" at the distal end 16 of the aerosol-generating article 10" when the aerosol-generating article 10" is inserted into the cylindrical receiving cavity 25".

[0117] The susceptor device 1 is arranged such that it is exposed to a magnetic field generated by the induction heating device of the aerosol generating device 23". Thus, when the induction heating device is activated, the susceptor device 1 heats up due to eddy currents and / or hysteresis losses (depending on the magnetic and electrical properties of the susceptor material of the susceptor device 1) induced by the alternating magnetic field. The susceptor device 1 is heated until it reaches an operating temperature sufficient to vaporize the aerosol-forming substrate 18 within the aerosol-generating article 10". Within the distal portion 28", the aerosol generating device 23" further comprises a DC power supply 29" and a controller 30 (at Figure 8 In addition to the induction coil 27 ″, the induction heating device is preferably at least partially an integrated part of the controller 30 ″.

[0118] For the purpose of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, quantities, percentages, etc. should be understood to be modified by the term "about" in all cases. In addition, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed in this article. Therefore, in this context, the number A is understood to be 5% of A±A. In this context, the number A can be regarded as including the numerical value within the general standard error for the measurement of the attribute modified by the number A. In some cases used in the appended claims, the number A can deviate from the percentages listed above, provided that the amount of A deviation does not substantially affect the basic characteristics and novel features of the invention claimed. In addition, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed in this article.

Claims

1. A susceptor device for inductively heating an aerosol-forming substrate, the susceptor device comprising: - at least one susceptor body having a susceptor body surface, said susceptor body comprising a first susceptor material; - a first heat diffusion layer comprising a first heat diffusion material, wherein the first heat diffusion layer extends across at least a portion of the susceptor body surface, is in thermal contact or thermal proximity with said portion of the susceptor body surface, and wherein the first heat diffusion material is a non-magnetic metal or non-magnetic metal alloy having a thermal conductivity that is at least 3.5 times, preferably 4 times, more preferably 5 times the thermal conductivity of the first susceptor material.

2. The susceptor device of claim 1, wherein the metal is selected from the group consisting of: copper, copper alloys, aluminum, and aluminum alloys.

3. A susceptor device according to claim 1 or 2, wherein the first heat diffusion layer has a thickness of 2 to 100 μm, preferably 3 to 60 μm, more preferably 5 to 20 μm, in particular 12 to 16 μm, for example 3 to 30 μm or 30 to 60 μm.

4. A susceptor arrangement according to any one of the preceding claims, wherein a spacer layer is arranged between the susceptor body and the first heat diffusion layer.

5. The susceptor device of claim 4, wherein the separator layer comprises at least one of an electrical insulating layer, an anti-diffusion layer, a temperature marking layer having a specific Curie temperature, and a protective layer.

6. A susceptor arrangement according to any one of the preceding claims, wherein the susceptor body is a substantially flat element and the susceptor body surface comprises a first susceptor body major surface and an opposing second susceptor body major surface.

7. The susceptor assembly of claim 6, wherein the first heat diffusion layer extends across at least a portion of the first susceptor body major surface, the susceptor assembly further comprising a second heat diffusion layer, the second heat diffusion layer comprising a second heat diffusion material, wherein the second heat diffusion layer extends across at least a portion of the second susceptor body major surface and is in thermal contact or thermal proximity with the portion of the second susceptor body major surface.

8. A susceptor arrangement according to claim 7, wherein the first heat diffusion layer extends across the entire first susceptor body major surface and / or the second heat diffusion layer extends across the entire second susceptor body major surface.

9. The susceptor device according to any one of claims 6 to 8, wherein the susceptor body is a multi-layer susceptor body.

10. A susceptor device for inductively heating an aerosol-forming substrate, the susceptor device comprising: - at least one susceptor body having a susceptor body surface, wherein the susceptor body is a substantially flat element and the susceptor body surface comprises a first susceptor body major surface and an opposing second susceptor body major surface, the susceptor body comprising a first susceptor material; - a first heat diffusion layer comprising a first heat diffusion material, wherein the first heat diffusion layer extends across at least a portion of the susceptor body surface, is in thermal contact or thermal proximity to said portion of the susceptor body surface, and wherein the first heat diffusion material is a metal having a thermal conductivity at least 3.5 times, preferably 4 times, more preferably 5 times the thermal conductivity of the first susceptor material, and wherein the first heat diffusion layer is at least partially coated with a temperature marking layer having a specific Curie temperature.

11. The susceptor device of claim 1 , wherein the metal is selected from the group consisting of: copper, copper alloys, nickel, nickel alloys, aluminum, and aluminum alloys.

12. A susceptor device according to claim 10 or 11, wherein the first heat diffusion layer has a thickness of 2 to 100 microns, preferably 3 to 60 microns, more preferably 5 to 20 microns, in particular 12 to 16 microns, such as 3 to 30 microns or 30 to 60 microns.

13. A susceptor arrangement according to any one of claims 10 to 12, wherein a spacer layer is arranged between the susceptor body and the first heat diffusion layer.

14. The susceptor assembly of claim 10, wherein the first heat diffusion layer extends across at least a portion of the first susceptor body major surface, the susceptor assembly further comprising a second heat diffusion layer, the second heat diffusion layer comprising a second heat diffusion material, wherein the second heat diffusion layer extends across at least a portion of the second susceptor body major surface and is in thermal contact or thermal proximity with the portion of the second susceptor body major surface.

15. A susceptor arrangement according to claim 14, wherein the first heat diffusion layer extends across the entire first susceptor body major surface and / or the second heat diffusion layer extends across the entire second susceptor body major surface.

16. The susceptor device according to any one of claims 10 to 15, wherein the susceptor body is a multi-layer susceptor body.

17. A susceptor device for inductively heating an aerosol-forming substrate, the susceptor device comprising: - at least one susceptor body having a susceptor body surface, said susceptor body comprising a first susceptor material; - a first heat diffusion layer comprising a first heat diffusion material, wherein the first heat diffusion layer extends across at least a portion of the susceptor body surface, is in thermal contact or thermal proximity with said portion of the susceptor body surface, and wherein the first heat diffusion material has a thermal conductivity that is at least 3.5 times, preferably 4 times, more preferably 5 times greater than the thermal conductivity of the first susceptor material, wherein the first heat diffusion material is a carbon allotrope, preferably graphite or graphene.

18. A susceptor arrangement according to claim 17, wherein the first heat spreading material is provided as a graphite sheet, preferably a pyrolytic graphite sheet.

19. A susceptor device according to claim 18, wherein the graphene sheet has a thickness of 1 to 200 microns, preferably 5 to 20 microns, more preferably substantially 10 microns.

20. A susceptor device according to any one of claims 17 to 19, wherein a spacer layer is arranged between the susceptor body and the first heat diffusion layer.

21. The susceptor device of claim 20, wherein the separator layer comprises at least one of an electrical insulating layer, an anti-diffusion layer, a temperature marking layer having a specific Curie temperature, and a protective layer.

22. A susceptor device according to any one of claims 17 to 21 wherein the susceptor body is a substantially flat element and the susceptor body surface comprises a first susceptor body major surface and an opposing second susceptor body major surface.

23. The susceptor assembly of claim 22, wherein the first heat diffusion layer extends across at least a portion of the first susceptor body major surface, the susceptor assembly further comprising a second heat diffusion layer comprising a second heat diffusion material, wherein the second heat diffusion layer extends across at least a portion of the second susceptor body major surface and is in thermal contact or proximity with the portion of the second susceptor body major surface.

24. A susceptor arrangement according to claim 23, wherein the first heat diffusion layer extends across the entire first susceptor body major surface and / or the second heat diffusion layer extends across the entire second susceptor body major surface.

25. A susceptor device according to any one of claims 22 to 24, wherein the susceptor body is a multi-layer susceptor body.

26. A susceptor device according to any of the preceding claims, wherein the first and / or second heat diffusing material has a thermal conductivity greater than 80 W / (mK), in particular greater than 100 W / (mK), more particularly greater than 200 W / (mK), preferably greater than 350 W / (mK), more preferably greater than 1000 W / (mK).

27. An inductively heatable aerosol-generating article comprising an aerosol-forming substrate and at least one susceptor device according to any preceding claim.

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