CN113667936B

CN113667936B - High-temperature antioxidant ultrathin heating film and preparation method thereof

Info

Publication number: CN113667936B
Application number: CN202111037127.7A
Authority: CN
Inventors: 刘磊
Original assignee: China Tobacco Hubei Industrial LLC
Current assignee: China Tobacco Hubei Industrial LLC
Priority date: 2021-09-06
Filing date: 2021-09-06
Publication date: 2023-08-25
Anticipated expiration: 2041-09-06
Also published as: CN113667936A

Abstract

The application relates to the technical field of electric heating films, in particular to a high-temperature oxidation-resistant ultrathin heating film and a preparation method thereof. The high-temperature oxidation-resistant ultrathin heating film sequentially comprises an insulating basal layer, a conductive layer, a transition layer and an oxidation layer, wherein the conductive layer comprises conductive metal or/and conductive ceramic, and the transition layer comprises incomplete oxidation oxide AO of metal A _x The highest valence to which A can be oxidized is a,0 < x < 0.5a; the oxide layer comprises a complete oxide BO of metal B _y The highest valence to which B can be oxidized is B, y=0.5b. The electric heating film has the advantages of good electric conduction effect and difficult warping and falling.

Description

High-temperature antioxidant ultrathin heating film and preparation method thereof

Technical Field

The application relates to the technical field of electric heating films, in particular to a high-temperature oxidation-resistant ultrathin heating film and a preparation method thereof.

Background

Numerous studies have shown that if the temperature of the cigarette is reduced below 500 ℃, the so-called "tobacco is heated but not combusted", the smoke can be substantially reduced for a number of harmful components, while the nicotine and aroma components are relatively less affected, and some of the aroma components may even increase due to reduced pyrolysis. Based on this idea, new concepts of "tobacco heating but not burning" have been developed. The cut tobacco of the tobacco product is heated only but not burnt, so that the release of harmful chemical components in the smoke is greatly reduced. The heating of non-combustible tobacco products is generally achieved by physically separating the tobacco from the heat source, and therefore one of the cores is heat source design development. The heating non-combustion tobacco products mainly use an electric heating type heat source, but the current commercial electric heating smoking set generally has the problem of uneven heating of the smoke releasing material, and the smoke releasing material can remain on the electric heating component after use due to coking, carbonization, bonding and other reasons, and a special tool is required to be matched for cleaning the heating component, so that the experience of consumers on the product is affected.

The electric heating film technology has the following basic principle: under the action of an electric field, electrons in the heating element move under the action of current to enhance and generate heat energy, and are externally transferred in the forms of conduction, radiation and convection, so that the heat energy has important application value in the fields of electronic appliances, heating, military, tobacco and the like. The heating uniformity and the service life can be greatly improved when the heating agent is applied to heating non-combustible cigarettes.

There are two conventional methods for manufacturing an industrially produced electric heating film, the first being sintering, in which a powder or a powder compact is heated to a temperature lower than the melting point of the essential components thereof, and then cooled to room temperature at a certain method and rate, as a result of which bonding between powder particles occurs, the strength of the sintered body increases, and aggregates of the powder particles become agglomerates of crystal grains, thereby obtaining an electric heating film of desired physical and mechanical properties. However, the method has complex manufacturing process and high energy consumption in the sintering process. The second type is buried wires, namely, a heat conducting wire is added into a heating plate, the thickness of a heating film is generally more than 1mm, and the miniaturization requirement of an electronic heating device is difficult to meet. Other preparation methods have been developed in the prior art, such as the method disclosed in the patent document with publication number CN101873729a, for the electric heating film and the preparation method thereof, a method of grinding the mixed powder of the adhesive, the conductive carbon black and the graphite powder and then coating the ground mixed powder on the fiber cloth is adopted. In another example, in the electric heating film with high heating efficiency disclosed in the patent publication No. CN109587841A and the preparation method thereof, the electric heating film consists of an electric heating layer, an insulating heat conducting layer and an insulating heat insulating layer, wherein the electric heating layer is formed by mixing mixed powder and an adhesive and then coating the mixed powder on a substrate material of the electric heating layer, the mixed powder consists of graphite powder, ce powder, Y powder and Cu powder with the particle size of less than 50nm, and the adhesive consists of dimethylbenzene, dimethylamide, polyurethane and polyimide polymer solution; the matrix material of the electric heating layer is polyimide, and the insulating heat conducting layer is an alumina ceramic layer.

Based on this, it can be found that the conventional electric heating film has the following drawbacks: (1) In the prior art, conductive carbon black and graphene are mostly used as conductive materials, and the materials have the advantage of difficult oxidation, but have relatively poor conductive effect compared with metals. (2) In the prior art, metal particles are added on the basis of graphite to enhance the conductive effect, but after metal is added, an anti-oxidation layer such as alumina is generally needed to prevent oxidation of the metal, and in the heating process of the electric heating film, the thermal expansion coefficients of the metal and the anti-oxidation layer are inconsistent, so that the problems of deformation, falling-off and the like of the electric heating film are easily caused. (3) The existing electric heating film is mostly prepared by mixing conductive particles with an adhesive, and has strict requirements on medicine precision and proportion during mixing, and the preparation method is complicated; and although the particle size of the conductive particles is about 50nm, after a large amount of particles and the adhesive are mixed, the thickness of the prepared electric heating film is more than 1mm, so that the application of the electric heating film in heating a non-burning cigarette appliance is limited.

Disclosure of Invention

The application aims to solve the problems and provide the high-temperature oxidation-resistant ultrathin heating film which has good conductive effect and is not easy to warp and fall off and the preparation method thereof.

The application provides a high-temperature oxidation-resistant ultrathin heating film, which sequentially comprises an insulating basal layer, a conductive layer, a transition layer and an oxidation layer, wherein the conductive layer comprises conductive metal or/and conductive ceramic, and the transition layer comprises incomplete oxide AO of metal A _x The highest valence to which A can be oxidized is a,0 < x < 0.5a; the oxide layer comprises a complete oxide BO of metal B _y The highest valence to which B can be oxidized is B, y=0.5b.

Preferably, the insulating substrate layer is made of a high-temperature resistant insulating material, and is preferably one or more of a ceramic sheet, a PI film and an insulating stainless steel sheet.

Preferably, the conductive metal includes one or more of Cr, ag, ti, cu, al, mo, W.

Preferably, the conductive ceramic comprises one or more of nitrides, carbides, oxides and borides of transition metals.

By fully oxidized oxide of a metal is meant that in this oxide, the metal is oxidized to the highest valence to which it can be oxidized; by partially oxidized oxide of a metal is meant that in this oxide the valence of the metal is lower than the highest valence to which the metal can be oxidized.

In the present application, the metal B preferably includes one or more of Cr, si, ti, al. As a preferred aspect of the present application, the metal a includes one or more of Cr, si, ti, al.

Wherein Cr has a valence of +3 and +6, but is hexavalent CrO ₃ Unstable, mostly Cr in a doubly polymerized form in solution ₂ O ₇ ² In the presence of oxygen, which oxidizes Cr up to a valence of 3 only during the reaction with oxygen, the fully oxidized oxide BO of Cr _y Refers to CrO _1.5 I.e. Cr ₂ O ₃ Incomplete oxide with CrO _x Indicating that 0 < x < 1.5.

The valence of Si is 0, +2, +4, wherein the highest valence is positive tetravalent. So that the fully oxidized oxide of Si means SiO ₂ Incomplete oxide of SiO _x Indicating that 0 < x < 2.

The valence of Ti is-1, 0, +2, +3, +4, wherein the highest valence is positive tetravalent. So the fully oxidized oxide of Ti is referred to as TiO ₂ The incomplete oxide is TiO _x Indicating that 0 < x < 2.

The maximum valence of Al is +3, and the fully oxidized oxide of Al is Al ₂ O ₃ Incomplete oxide with AlO _x Indicating that 0 < x < 1.5.

In the application, the conductive metal is used as the conductive layer, so that the conductive layer has the advantage of good conductive effect, thereby having good heating effect. Meanwhile, in order to prevent the conductive metal from being oxidized to influence the conductive effect when the conductive metal is used for a long time, the application also designs an oxide layer on the conductive layer, and the surface layer compact oxide layer isolates air and protects the conductive layer from being oxidized, so that the heating film can work stably. Although an oxide layer is designed, a transition layer is also designed between the conductive layer and the oxide layer. In the heating process, the distance between metal atoms of the conductive layer is larger, so that the thermal expansion degree of the conductive layer is larger; the smaller distance between the oxide layer metal oxide atoms results in a smaller degree of thermal expansion thereof; the distance between the incomplete oxide atoms of the transition layer is between the two distances, and the buffer effect is achieved. And due to the existence of the transition layer, the stress caused by different thermal expansion coefficients of the conductive layer and the oxide layer can be relieved, and the coating is prevented from falling off.

In order to further improve the buffer capacity, it is preferable that the metal content per unit volume in the transition layer is not more than the metal content per unit volume in the conductive layer and not less than the metal content per unit volume in the oxide layer. At the same volume, if the metal content of each layer is the same, the distance between the atoms naturally decreases in the transition layer due to the increase of oxygen atoms, resulting in a decrease in the degree of thermal expansion relative to the conductive layer, at which time, by decreasing the metal content in the transition layer while also decreasing the metal-bonded atoms, the distance between the atoms in the transition layer increases relatively in the same volume, so that the degree of thermal expansion is reduced less than that of the conductive layer, thereby reducing the risk of warping thereof. The mechanism by which the oxide layer further reduces the metal content is the same.

The electric heating film is mainly used for heating the heating smoking set of the non-combustible cigarettes, and the smoking set belongs to a micro structure, so that the thickness of the electric heating film needs to be made lower in order to improve the adaptation degree of the electric heating film.

Preferably, the thickness of the conductive layer is 0.1-50 μm.

Preferably, the thickness of the transition layer is 0.1-10 μm.

Preferably, the thickness of the oxide layer is 0.1-10 μm.

In the prior art, the method for preparing the electric heating film by mixing the adhesive and the conductive particles is difficult to achieve the thickness, so another object of the application is to provide a preparation method of a high-temperature oxidation-resistant ultrathin heating film, which comprises the following steps:

s1, depositing a conductive layer on the insulating basal layer; the thickness of the conductive layer is adjusted by controlling the deposition time, and a set resistance value is obtained;

s2, controlling the flow ratio of oxygen to the metal A so that the oxygen can not lead the metal A to be completely oxidized, and depositing a transition layer on the conductive layer;

s3, controlling the flow ratio of the oxygen to the metal B, so that the oxygen inlet can enable the metal B to be completely oxidized, and depositing an oxide layer on the transition layer.

The deposition method may be a chemical vapor deposition method or a physical vapor deposition method, preferably a physical vapor deposition method, and more preferably a magnetron sputtering method in the physical vapor deposition method.

In the application, the conductive layer, the transition layer and the oxide layer are directly and sequentially compounded on the insulating basal layer in a deposition mode, so that the use of an adhesive is avoided, the heat conducting performance is improved, and the thickness of each layer is reduced; and the thickness of each layer can be controlled by controlling the metal inlet amount and the deposition time during deposition, so that the thickness of the conductive layer can be arbitrarily designed according to the requirements of heating power and rated voltage to adjust the resistance value, and the application range is wide.

As the preference of the application, the deposition is carried out under the conditions of bias voltage of 0.1-500V, power of 10-500W and internal pressure of 0.1-10 Pa.

The application has the beneficial effects that:

1. the application provides a novel high-temperature oxidation-resistant heating film and a preparation method thereof, which have the advantages that the preparation method is simple, the preparation of a three-layer structure on a substrate can be finished by means of a film coating technology, the thickness is thinner, the overall thickness is below hundreds of micrometers, the geometric dimension of a device is not obviously increased after the film is deposited on a miniature device, and the film is easy to compound with the miniature device.

2. The heating film provided by the application has the advantages that the problem of film heating and warping is avoided due to the existence of the transition layer, and meanwhile, the coating can be kept firm and the durability is strong under the conditions of external blade coating and the like.

Drawings

FIG. 1 is a schematic diagram of a high temperature oxidation resistant ultra-thin heating film;

in the figure: an insulating base layer 1, a conductive layer 2, a transition layer 3 and an oxide layer 4.

Detailed Description

The following is a specific embodiment of the present application, and the technical solution of the present application is further described with reference to the accompanying drawings, but the present application is not limited to these examples.

Example 1

A high-temperature oxidation-resistant ultrathin heating film is shown in fig. 1, and sequentially comprises an insulating basal layer 1, a conductive layer 2, a transition layer 3 and an oxidation layer 4.

It is prepared by the following steps:

s1, a ceramic plate with the thickness of 100 mu m is adopted as an insulating basal layer, a Cu target is adopted as a sputtering source material by utilizing a magnetron sputtering technology, and the deposition is carried out for 60 minutes, so that a layer of Cu with the thickness of 5 mu m can be plated on the insulating basal layer to serve as a conducting layer.

S2, using a magnetron sputtering technology, taking a Cr target as a sputtering source material, and introducing a lower oxygen flow of 1mL/min to ensure that Cr is not completely oxidized, wherein the deposition time is 15min, so that an oxide film with the thickness of 1 mu m can be plated on the conductive layer to serve as a transition layer.

Since the amount of oxygen introduced is insufficient, cr cannot be completely oxidized to Cr ₂ O ₃ At this time, the metal oxide in the transition layer is aCr bCr ₂ O ₃ Considering that the ratio of a to b is different due to the different flow rates of oxygen and Cr, and the loss of oxygen and Cr exists in the deposition process, the ratio of a to b is uncertain, so the metal oxide is directly recorded as CrO _x 0 < x < 1.5, as in the examples below.

S3, using a magnetron sputtering technology, taking a Cr target as a sputtering source material, introducing high oxygen flow rate of 3 mL/min to completely oxidize Cr, and depositing for 15min to plate an oxide film of Cr with the thickness of 1 mu m on the conductive layer to serve as an oxide layer.

Wherein, the magnetron sputtering parameters are bias voltage 50V, power 250W and air pressure 0.7Pa in the cavity.

Since the surface areas of the conductive layer, the transition layer and the oxide layer are substantially the same, in this embodiment, the metal content per unit volume in the transition layer and the oxide layer is substantially the same and is lower than the metal content per unit volume in the conductive layer by controlling the metal flux and the deposition time.

Example 2

The high temperature oxidation resistant ultrathin heating film sequentially comprises an insulating basal layer, a conducting layer, a transition layer and an oxidation layer.

It is prepared by the following steps:

s1, adopting a stainless steel sheet with the thickness of 150 mu m as an insulating basal layer, utilizing a magnetron sputtering technology, taking an Ag target as a sputtering source material, depositing for 60min, and plating an Ag layer with the thickness of 6 mu m on the insulating basal layer to serve as a conductive layer.

S2, using a magnetron sputtering technology, taking a Cr target as a sputtering source material, and introducing a lower oxygen flow of 1mL/min to ensure that Cr is not completely oxidized, wherein the deposition time is 25min, so that an oxide film of Cr with the thickness of 1.2 mu m can be plated on the conductive layer to serve as a transition layer. . Since the amount of oxygen introduced is insufficient, cr cannot be completely oxidized to Cr ₂ O ₃ At this time, the metal oxide in the transition layer is CrO _x ，0＜x＜1.5。

S3, using a magnetron sputtering technology, taking an Al target as a sputtering source material, introducing high oxygen flow rate of 3 mL/min to enable the Al to be completely oxidized, and enabling the deposition time to be 25min, so that an oxide film of the Al with the thickness of 1.2 mu m can be plated on the conductive layer to serve as an oxide layer.

Wherein, the magnetron sputtering parameters are bias voltage 100V, power 250W and air pressure 0.7Pa in the cavity.

By controlling the oxygen inlet amount and the deposition time, the metal content of the unit volume in the oxide layer is less than the metal content of the unit volume in the transition layer and less than the metal content of the unit volume in the conductive layer.

Example 3

The preparation method comprises the following steps:

s1, adopting a PI film with the thickness of 80 mu m as an insulating basal layer, utilizing a magnetron sputtering technology, taking an Ag target as a sputtering source material, depositing for 300min, and plating an Ag layer with the thickness of 50 mu m on the insulating basal layer to serve as a conductive layer.

S2, using a magnetron sputtering technology, taking a Si target as a sputtering source material, respectively introducing oxygen with lower flow rate of 2mL/min, depositing for 50min, and plating a Si oxide film with the thickness of 5 mu m on the conductive layer to serve as a transition layer. Since the amount of oxygen introduced is insufficient, si cannot be completely oxidized to SiO ₂ At this time, the metal oxide in the transition layer is SiO _x ，0＜x＜2。

S3, using a magnetron sputtering technology, taking an Al target as a sputtering source material, introducing high oxygen flow of 5mL/min to enable the Al to be completely oxidized, depositing for 100min, and plating a layer of Al with the thickness of 10 mu m on the transition layer ₂ O ₃ As an oxide layer.

Wherein, the magnetron sputtering parameters are bias voltage 500V, power 500W and air pressure 5Pa in the cavity.

The metal content of the unit volume of the oxide layer is less than the metal content of the unit volume of the transition layer and less than the metal content of the unit volume of the conductive layer by controlling the metal inflow and the deposition time.

Example 4

It is prepared by the following steps:

s1, a PI film with the thickness of 80 mu m is adopted as an insulating basal layer, a magnetron sputtering technology is utilized, a Ti target is adopted as a sputtering source material, the deposition is carried out for 40min, and a layer of Ti with the thickness of 2 mu m is plated on the insulating basal layer to be used as a conducting layer.

S2, using a magnetron sputtering technology, taking a Cr target as a sputtering source material, introducing low-flow oxygen gas of 0.5 mL/min, depositing for 20min, and plating a Cr oxide film with the thickness of 1 mu m on the conductive layer to serve as a transition layer. Since the amount of oxygen introduced is insufficient, cr cannot be completely oxidized to Cr ₂ O ₃ At this time, the metal oxide in the transition layer is CrO _x ，0＜x＜1.5。

S3, using a magnetron sputtering technology, taking a Ti target as a sputtering source material, and introducing higher oxygenThe flow is 5mL/min, the deposition time is 20min, and a layer of TiO with the thickness of 1 mu m is plated on the transition layer ₂ As an oxide layer.

Wherein, the magnetron sputtering parameters are bias voltage 10V, power 200W and air pressure 0.3Pa in the cavity.

The metal content of the unit volume in the oxide layer, the transition layer and the conductive layer is basically the same through controlling the oxygen inlet amount and the deposition time.

Example 5

It is prepared by the following steps:

s1, a PI film with the thickness of 200 mu m is used as an insulating basal layer, an Al target is used as a sputtering source material by utilizing a magnetron sputtering technology, the deposition is carried out for 8min, and a layer of Al with the thickness of 1 mu m is plated on the insulating basal layer to be used as a conducting layer.

S2, using a magnetron sputtering technology, taking a Cr target as a sputtering source material, wherein the oxygen inlet flow is 1mL/min, the deposition time is 5min, and plating a Cr oxide film with the thickness of 0.5 mu m on the conductive layer to serve as a transition layer. Since the amount of oxygen introduced is insufficient, cr cannot be completely oxidized to Cr ₂ O ₃ At this time, the metal oxide in the transition layer is CrO _x ，0＜x＜1.5。

S3, using a magnetron sputtering technology, taking a Cr target as a sputtering source material, wherein the oxygen inlet flow is 4mL/min, the deposition time is 7min, and plating a layer of Cr with the thickness of 0.8 mu m on the transition layer ₂ O ₃ As an oxide layer.

Wherein, the magnetron sputtering parameters are bias voltage 200V, power 300W and air pressure 1Pa in the cavity.

The metal content per unit volume in the oxide layer is larger than the metal content per unit volume in the transition layer by controlling the metal inflow and the deposition time, but the oxide layer and the transition layer are smaller than the metal content per unit volume in the conductive layer.

Example 6

It is prepared by the following steps:

s1, adopting a PI film with the thickness of 80 mu m as an insulating basal layer, utilizing a magnetron sputtering technology, taking an Al target as a sputtering source material, depositing for 10min, and plating a layer of Al with the thickness of 1.1 mu m on the insulating basal layer to serve as a conductive layer.

S2, using a magnetron sputtering technology, taking an Al target as a sputtering source material, introducing oxygen with the flow of 2mL/min, depositing for 5min, and plating an Al oxide film with the thickness of 0.6 mu m on the conductive layer to serve as a transition layer. Since the amount of oxygen introduced is insufficient, al cannot be completely oxidized to Al ₂ O ₃ At this time, the metal oxide in the transition layer is AlO _x ，0＜x＜1.5。

S3, using a magnetron sputtering technology, taking an Al target as a sputtering source material, introducing oxygen with a flow of 5mL/min and a deposition time of 4min, and plating an Al layer with a thickness of 0.5 mu m on the transition layer ₂ O ₃ As an oxide layer.

Wherein, the magnetron sputtering parameters are bias voltage 400V, power 200W and air pressure 3Pa in the cavity.

Comparative example 1

This comparative example is substantially the same as example 1, except that: no transition layer is contained.

It is prepared by the following steps:

and (3) taking a ceramic sheet with the thickness of 100 mu m as an insulating basal layer, taking a Cu target as a sputtering source material by utilizing a magnetron sputtering technology, and depositing for 60 minutes, so that a layer of Cu with the thickness of 5 mu m can be plated on the insulating basal layer to serve as a conductive layer.

By using a magnetron sputtering technology, a Cr target is used as a sputtering source material, a higher oxygen flow rate of 3 mL/min is introduced to fully oxidize Cr, the deposition time is 15min, and an oxide film with the thickness of 1 mu m can be plated on the conductive layer to be used as an oxide layer.

Comparative example 2

This comparative example refers to the data in example 1 of the patent document publication No. CN101873729a, in which the conductive layer is a mixture of conductive carbon black, graphite powder and polyimide resin, excluding the transition layer, and is coated with a PET film.

It is prepared by the following steps:

weighing the following materials in weight: 4.0kg of graphite powder with the particle diameter of 1-10 mu m; 4.0kg of conductive carbon black with the particle diameter of 10-100 nm; 100kg of polyimide resin; 90kg of dimethylacetamide.

Firstly, mixing conductive carbon black and graphite powder to obtain mixed powder, then mixing polyimide resin and the mixed powder, and adding a diluent for dilution; grinding for 10-60 min under stirring speed of 250-500 rpm, adding dimethylacetamide as diluent, and mixing to obtain a gel mixture with viscosity of 180-250 mmpa.s.

Coating the gelatinous mixture on a ceramic sheet with the thickness of 100 mu m by a coating machine, baking, immersing the gelatinous mixture and solidifying to form an electric heating film; the temperature in the baking process is gradually increased from 100 ℃ to 300 ℃. And then wrapping PET films on the upper and lower surfaces of the electrothermal film at 110+/-10% by using a film laminating machine to prepare the electrothermal film with the thickness of 0.6 mm.

Comparative example 3

This comparative example refers to the data of example 1 in the patent document with publication No. CN109587841 a.

The method comprises the following steps:

(1) Preparing an insulating layer: a layer of aluminum film is plated on one surface of a 100 mu m polyimide flexible substrate layer by adopting a direct current magnetron sputtering technology, and the aluminum film with the thickness of 0.03mm is prepared by controlling sputtering power, gas pressure and tape feeding speed.

(2) Preparing electric heating layer slurry: weighing graphite powder, ce powder, Y powder and Cu powder with the particle size of 50nm at the mass ratio of 12:2:3:6, mixing to obtain mixed powder, adding an adhesive into the mixed powder according to the mass ratio of 2:10, fully mixing and grinding to obtain the electric heating layer slurry, wherein the adhesive is formed by mixing dimethylbenzene, dimethylamide, polyurethane and polyimide polymer solution at the mass ratio of 1:2:1:4.

(3) Coating the electric heating layer slurry on a polyimide substrate material by a coating machine, baking by heating and drying equipment, immersing and curing the electric heating layer on the polyimide substrate material to form an electric heating film, wherein the temperature in the baking process is gradually increased from 100 ℃ to 300 ℃, and the heating speed is controlled at 30 min/DEG C; the heat preservation time is 30min;

(4) Implanting an electrode on the electric heating film, wherein the electrode is made of copper foil or aluminum foil;

(5) Plating an alumina ceramic layer on one surface of the electric heating film coated with the electric heating layer slurry by adopting a direct current sputtering technology; the specific requirements of direct current sputtering are as follows: ar/O in sputtering working gas by taking high-purity aluminum as target material ₂ The flow ratio of (2) is 12:1, the working air pressure is 1.0Pa, the sputtering power is 50W, and the heat treatment temperature is 200 ℃;

(6) And wrapping the insulating heat-insulating layer on the heating layer matrix material by adopting a film coating machine, wherein one surface of the insulating heat-insulating layer plated with an aluminum film contacts with the heating layer matrix material during wrapping.

[ thickness detection ]

The thicknesses of the electrically heated films produced in examples and comparative examples were measured, respectively, and the detection results are shown in table 1 below.

[ warpage detection ]

The electrically heated films in examples and comparative examples were cut into pieces of 11 x 20cm (20 cm in the longitudinal direction), the pieces were placed on a horizontal plane, the pieces were energized for 1 hour, and the degree of warpage was represented by the angle θ between the end points of the pieces and the horizontal plane, and the detection results were as shown in table 1 below.

[ conductivity detection ]

The area specific resistances of the electrically heated films in examples and comparative example 1 before the transition layer and the oxide layer were respectively measured, and the area specific resistances of the electrically heated films in comparative examples 2, 3 before the insulating film (layer) was coated, and the detection results are shown in table 1 below.

Table 1.

As can be seen from table 1, the electric heating film prepared by the application has smaller thickness and smaller specific area resistance, and can be used for heating non-combustible cigarette smoking articles. In example 4, the conductive layer is thin, so the area specific resistance is large; in example 5, since the metal content per unit volume in the oxide layer was made larger than that in the conductive layer by controlling the flow rate and the deposition time, the warpage thereof was relatively increased, but the overall performance remained superior to that of the comparative example. In comparative example 1, the transition layer was reduced, and although the specific resistance of the thickness and area was improved, the warpage was greatly increased, which was disadvantageous for long-term use of the electric heating film. The electrically heated films of comparative examples 2 and 3, although not prone to warping, have high specific resistance to thickness and area, and are unsuitable for use in heating non-combustible cigarette smoking articles.

The specific embodiments described herein are offered by way of example only to illustrate the spirit of the application. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the application or exceeding the scope of the application as defined in the accompanying claims.

Claims

1. The utility model provides a high temperature oxidation resistance ultra-thin heating film which characterized in that: comprises an insulating basal layer (1), a conductive layer (2), a transition layer (3) and an oxide layer (4) in sequence, wherein the conductive layer (2) comprises conductive metal or/and conductive ceramic, and the transition layer (3) comprises incomplete oxide AO of metal A _x The highest valence to which A can be oxidized is a,0 < x < 0.5a; the oxide layer (4) comprises a fully oxidized oxide BO of a metal B _y The highest valence to which B can be oxidized is B, y=0.5b;

the metal content of the transition layer (3) per unit volume is not more than the metal content of the conductive layer (2) per unit volume and not less than the metal content of the oxide layer (4) per unit volume;

the thickness of the conductive layer (2) is 0.1-50 mu m;

the thicknesses of the transition layer (3) and the oxide layer (4) are respectively 0.1-10 mu m.

2. The high temperature oxidation resistant ultra thin heating film according to claim 1, wherein: the conductive metal comprises one or more of Cr, ag, ti, cu, al, mo, W; the conductive ceramic comprises one or more of transition metal nitrides, carbides, oxides and borides.

3. The high temperature oxidation resistant ultra thin heating film according to claim 1, wherein: the metal B comprises one or more of Cr, si, ti, al.

4. The high temperature oxidation resistant ultra thin heating film according to claim 1, wherein: the metal A comprises one or more of Cr, si, ti, al.

5. A method for preparing the high-temperature oxidation-resistant ultrathin heating film according to any one of claims 1 to 4, which is characterized in that: the method comprises the following steps:

s1, depositing a conductive layer (2) on the insulating basal layer (1);

s2, controlling the flow ratio of oxygen to the metal A so that the oxygen can not lead the metal A to be completely oxidized, and depositing a transition layer (3) on the conductive layer (2);

s3, controlling the flow ratio of oxygen to the metal B, so that the oxygen inlet can enable the metal B to be completely oxidized, and depositing an oxide layer (4) on the transition layer (3).

6. The method for preparing the high-temperature oxidation-resistant ultrathin heating film according to claim 5, which is characterized in that: the deposition is carried out under the bias voltage of 0.1-500V, the power of 10-500W and the internal air pressure of 0.1-10 Pa.

7. The method for preparing the high-temperature oxidation-resistant ultrathin heating film according to claim 6, which is characterized in that: all adopt magnetron sputtering method to deposit.