阅读说明：本技术 一种石墨烯/贱金属合金导电材料、电阻浆料、发热体及其制备和应用 (A kind of graphene/lowpriced metal alloy conductive material, resistance slurry, heater and its preparation and application ) 是由 周宏明 王博益 刘宁 包志强 于 2018-05-21 设计创作，主要内容包括：本发明属于导电材料领域,具体涉及一种石墨烯/贱金属合金导电材料,其特征在于,包含石墨烯,合金粉和玻璃粉。本发明还提供了包含所述导电材料的导电浆料；包含所述导电材料的发热体；本发明还提供了所述的发热体的制备方法和应用。本发明所述的导电材料具有优良性能,由其制得的膜发热体具有安全性好,成本低,导电性好,结合力强,加热速度快等优点,特别适合应用于烫发棒中。(The invention belongs to conductive material fields, and in particular to a kind of graphene/lowpriced metal alloy conductive material, which is characterized in that include graphene, alloyed powder and glass powder.The present invention also provides the electrocondution slurries comprising the conductive material；Heater comprising the conductive material；The present invention also provides the preparation method and application of the heater.The advantages that conductive material of the present invention has excellent performance, and film heater as made from it has safety good, at low cost, and good conductivity, binding force is strong, and heating speed is fast, particularly suitable in permanent lod.)

1. a kind of graphene/lowpriced metal alloy conductive material, which is characterized in that include graphene, alloyed powder and glass powder.

2. graphene as described in claim 1/lowpriced metal alloy conductive material, which is characterized in that glass powder is devitrified glass, Its solid-phase component is SiO₂-Al₂O₃-CaO-MgO-B₂O₃-Bi₂O₃-Bi₂O₃；Fusing point is 600 DEG C~800 DEG C.

Preferably, the alloyed powder is at least one of NiB, NiCu, NiFe, NiAlCr；

Preferably, the graphene is multi-layer graphene, with a thickness of 1nm~100nm.

3. graphene as claimed in claim 1 or 2/lowpriced metal alloy conductive material, which is characterized in that the parts by weight of alloyed powder It is 45~90 parts；The parts by weight of graphene are 1~10 part；The parts by weight of glass powder are 1~15 part.

4. a kind of doped graphene resistance alloys slurry, which is characterized in that include the described in any item graphite of claims 1 to 3 Alkene/lowpriced metal alloy conductive material and organic carrier；

Preferably, the organic carrier includes solvent, thickener, thixotropic agent, surfactant and binder.

5. doped graphene resistance alloys slurry as claimed in claim 4, which is characterized in that

In the organic carrier, solvent, thickener, thixotropic agent, surfactant and binder mass parts ratio be 85-93: 8-14:1-4:1-4:1-8；

The mass percent that organic carrier accounts for the doped graphene resistance alloys slurry is 10%~30%；

The solvent is terpinol, butyl acetate, one or more in dibutyl phthalate.

6. a kind of doped graphene alloy heat generating film heater of stainless base steel, which is characterized in that include stainless steel base, phase Pair two planes be compounded with thermal insulation layer and dielectric layer 1 respectively；1 surface recombination of dielectric layer has dielectric layer 2；2 table of dielectric layer Face is compounded with resistance alloys layer；Resistance alloys layer surface is compounded with insulated thermal insulating layer；

The resistance alloys layer contains the described in any item graphenes of claims 1 to 3/lowpriced metal alloy conductive material；It is excellent Choosing is obtained by the described in any item doped graphene resistance alloys slurry curings of claim 4~5.

7. the doped graphene alloy heat generating film heater of stainless base steel as claimed in claim 6, which is characterized in that described Dielectric layer 1 contains glass 1, and the dielectric layer 2 contains glass 2；

The fusing point of glass 1 is 800 DEG C~1000 DEG C；The fusing point of glass 2 is 600 DEG C~800 DEG C；

Preferably, the glass 1 is devitrified glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃；

Preferably, the glass 2 is devitrified glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃-Bi₂O₃。

8. a kind of preparation of the doped graphene alloy heat generating film heater of the described in any item stainless base steels of claim 6~7 Method, which comprises the following steps:

Step 1: stainless steel substrate surface is pre-processed；

Step 2: solvent, thickener, thixotropic agent, surfactant, binder are mixed, organic carrier is obtained；

Step 3: glass 1, glass 2 are mixed with organic carrier respectively, respectively obtain dielectric paste 1 and dielectric paste 2；

Step 4: dielectric paste 1 is compounded in a plane of pretreated stainless steel substrate, dry, sintering, stainless The dielectric layer 1 is formed on steel substrate；Then the surface recombination dielectric paste 2 of dielectric layer 1, drying are sintered, in dielectric layer again 1 surface forms the dielectric layer 2；

Step 5: alloyed powder, Graphene powder, glass powder are mixed, the graphene/lowpriced metal alloy conductive material is obtained；

Step 6: it mixes, obtains by organic carrier is prepared into the graphene/lowpriced metal alloy conductive material and step 2 The doped graphene resistance alloys slurry；

Step 7: doped graphene resistance alloys slurry is compounded on the dielectric layer 2 in step 4, dry, sintering, in medium The resistance alloys layer is formed on layer 2；

Step 8: the resistance alloys layer that step 7 is obtained sprays one layer of insulated heat slurry；Stainless steel substrate compound medium layer 1 Opposite face spray one layer of insulating heat-conductive slurry, it is dry, obtain the doped graphene alloy heat generating film hair of the stainless base steel Hot body.

9. preparation method as claimed in claim 8, it is characterised in that: the stainless steel substrate is a kind of in 430,304,316；

Preferably, in step 4,1 sintering process of dielectric layer are as follows: in air, with 2 DEG C/min~10 DEG C/min heating speed Rate keeps the temperature 1h~5h to 300 DEG C~500 DEG C, then with 0.5 DEG C/min~10 DEG C/min heating rate to 800 DEG C~1000 DEG C, Keep the temperature 1h~5h；

Preferably, 2 sintering process of dielectric layer are as follows: in air, with 2 DEG C/min~10 DEG C/min heating rate to 300 DEG C~500 DEG C, 1h~5h is kept the temperature, then with 0.5 DEG C/min~10 DEG C/min heating rate to 600 DEG C~800 DEG C, keeps the temperature 1h~5h；

In step 7, resistance alloys layer sintering process are as follows: vacuum degree be 10^-4~10^-3In Pa vacuum, with 2 DEG C/min~10 DEG C/ Min heating rate keeps the temperature 0.5h~2h, then with 0.5 DEG C/min~10 DEG C/min heating rate to 600 to 300 DEG C~500 DEG C DEG C~800 DEG C, keep the temperature 0.5h~3h.

10. any one of heater described in a kind of claim 6-7 or claim 8~9 preparation method hair obtained The application of hot body, it is characterised in that: the application includes being applied in permanent lod.

Technical field

The present invention relates to a kind of doped graphene alloy heat generating film preparation of stainless base steel and its applications, and in particular to stainless Application of the doped graphene alloy heat generating film heater of base steel in permanent lod.

Background technique

It is existing with the problems such as traditional heating mode reflected service life is short, heating method is not flexible, heating efficiency is low Traditional heating mode be no longer satisfied existing needs, Electric radiant Heating Film constantly came out as the product of heating element in recent years, And ceramic base, glass base, polymer matrix, Metal Substrate can be divided by substrate according to thick-film heating element, wherein Metal Substrate belongs to not The steel substrate that becomes rusty be it is most widely used, stainless base steel heating element have power density it is big, it is small in size, be easily installed and anti-vibration etc. is all More advantages.But since insulating properties of the stainless base steel heating film to substrate requires high, heating speed, anti-oxidant energy to heating film The performance indicators such as power, binding force all have higher requirements.If Chinese patent is " based on the large power thick film circuit of stainless steel substrate with leading Plasma-based material and its preparation process " (application number: 02139895.X) describe silver-colored palladium resistance slurry printing stainless steel substrate as big Power circuit.Due to using noble metal as conductive phase, production cost is considerably increased, heating film inoxidizability is poor；Again Then silver is easy migration during the sintering process, the insulating properties of the stainless steel substrate it is difficult to ensure that.As Chinese patent " is based on stainless base steel YBCO thick-film resistor paste of plate and preparation method thereof " (it is thick 201010158934) application number: to describe stainless steel substrate YBCO Film resistance.Due to the higher cost using synthesis in solid state YBCO, purity is lower, and there are production cost or excessively high, thermal expansion systems The disadvantages of number matching is poor, and the electric conductivity of resistive film is poor, and electrothermal calefactive rate is affected.Therefore, current urgent to be essential It asks and exactly finds a kind of low cost, good conductivity, the thick film heating resistance material highly-safe, heating speed is fast.

Summary of the invention

To solve the deficiencies in the prior art, an object of the present disclosure is, it is conductive to provide a kind of graphene/lowpriced metal alloy A kind of material (present invention also abbreviation conductive material or electrically conductive composition), it is desirable to provide conduction material with excellent conductive performance Material.

Second purpose of the invention is, provides a kind of comprising the doping of the graphene/lowpriced metal alloy conductive material Graphene resistance alloys slurry.

For at high cost, the poorly conductive that solves existing stainless steel substrate thick film heating film, binding force is poor, heating speed slowly Defect.Third purpose of the present invention is, it is desirable to provide one kind includes the graphene/lowpriced metal alloy conductive material, and is had The doped graphene alloy heat generating film heater of the stainless base steel of one brand new characteristic.

4th purpose of the invention is, provides a kind of preparation of the doped graphene alloy heat generating film heater of stainless base steel Method.

5th purpose of the invention is, provides a kind of answering for the doped graphene alloy heat generating film heater of stainless base steel With.

A kind of graphene/lowpriced metal alloy conductive material includes graphene, alloyed powder and glass powder.

Raw material and production can be substantially reduced by the collaboration between component using conductive material of the present invention Cost；Moreover, it can also aid in the densification for the heating film for being sintered the conductive material, reduce the heating film that sintering obtains Defect, make heating film have higher stability.In addition, present invention doped graphene in lowpriced metal alloy is used as a part Conductive phase can greatly increase the electric conductivity of film, simultaneously because it increases alloy conductive particle and glass with lamellar structure Glass binder and bond strength with dielectric layer, doped graphene adjust the work of the thermal expansivity of film layer wherein also functioning to simultaneously With these all enhance the mechanical anti-thermal shock characteristic of film layer, improve the stability of film, extend the service life of heater.

Preferably, glass powder fusing point is 600 DEG C~800 DEG C in the graphene/lowpriced metal alloy conductive material.

Further preferably, glass powder is devitrified glass.

Still more preferably, the solid-phase component of the glass powder is SiO₂-Al₂O₃-CaO-MgO-B₂O₃-Bi₂O₃。

Preferably, the alloyed powder is at least one of NiB, NiCu, NiFe, NiAlCr.It is closed using base metal Gold replaces noble metal, reduces the cost of raw material, while alloy and graphene cooperation, can also reduce sintering temperature, make Film can be sintered more densification and reduce defect, reduce process costs, improve the stability of film layer.

Still more preferably, the alloyed powder is NiB.The study found that using NiB and graphene and the glass Synergy it is more excellent, resistance variations caused by film layer sweeps away the thermal pressure of generation also in heat can be further reduced, mentioned significantly The stability of high film layer.

Preferably, the graphene is multi-layer graphene, with a thickness of 1nm~100nm.The graphene of the preferred thickness and its His ingredient synergy is good, can further coordinated regulation film layer electric conductivity.

Preferably, the parts by weight of alloyed powder are 45~90 parts in the graphene/lowpriced metal alloy conductive material； The parts by weight of graphene are 1~10 part；The parts by weight of glass powder are 1~15 part.It is small in the component collaboration, in the preferred model Effect under enclosing is more excellent.

The present invention also provides a kind of doped graphene resistance alloys slurries, include the graphene/lowpriced metal alloy Conductive material and organic carrier.

Preferably, the organic carrier includes solvent, thickener, thixotropic agent, surfactant and binder.

The solvent is terpinol, butyl acetate, one or more in dibutyl phthalate.Into One step is preferred, and the solvent is the mixture of terpinol, butyl acetate, dibutyl phthalate.

The thickener can be the interior conventional material with thickening effect of industry, preferably ethyl cellulose.

The thixotropic agent can be the interior conventional material with anti-thixotroping of industry, preferably rilanit special.

The surfactant can be the conventional material with raising surface-active in industry, preferably oleic acid.

The binder can mention highly viscous conventional material, preferably polyvinyl butyral to have in industry.

Preferably, in the organic carrier, the mass parts of solvent, thickener, thixotropic agent, surfactant and binder Ratio is 85-93: 8-14: 1-4: 1-4: 1-8.

Preferably, organic carrier account for the mass percent of the doped graphene resistance alloys slurry be 10%~ 30%.Surplus is the graphene/lowpriced metal alloy conductive material.

Further preferably, in the doped graphene resistance alloys slurry, as mass fraction, alloyed powder 45%~ 90%, graphene 1%~10%, glass powder 1%~15%, organic carrier 10%~30%.

The present invention also provides a kind of doped graphene alloy heat generating film heaters of stainless base steel, include stainless base steel Bottom, two opposite planes are compounded with thermal insulation layer and dielectric layer 1 respectively；1 surface recombination of dielectric layer has dielectric layer 2；It is situated between 2 surface recombination of matter layer has resistance alloys layer；Resistance alloys layer surface is compounded with insulated thermal insulating layer；

The resistance alloys layer contains the graphene/lowpriced metal alloy conductive material.

The present invention provides a kind of brand new and have innovation ingredient advantage stainless base steel doped graphene alloy Heating film heating-body；The longitudinal section of the doped graphene alloy heat generating film heater of the stainless base steel is (perpendicular to the hair The section in the direction of hot body plane) it is successively compound thermal insulation layer, stainless steel substrate, dielectric layer 1, dielectric layer 2, alloy electricity Resistance layer and insulated thermal insulating layer.

Heater of the present invention, stainless steel substrate is as substrate, with excellent heating conduction, and has excellent Mechanical performance, resistance material (slurry) of the present invention use on stainless base steel as fever film layer, can satisfy stainless base steel The high-power use of heater can sustain powerful thermal shock, and heating efficiency is high, also high using temperature.Moreover, The present invention also innovatively makes substrate, dielectric layer, alloy using compound dielectric layer (successively compound dielectric layer 1 and dielectric layer 2) Resistive layer more preferably carries out the collaboration matching of thermal expansivity, enhance while increasing substrate insulating properties mutual bond strength and Stability.

Preferably, the resistance alloys layer is obtained by the doped graphene resistance alloys slurry curing.

The present invention, the dielectric layer 1 contain glass 1, and the dielectric layer 2 contains glass 2；

The fusing point of glass 1 is 800~1000 DEG C；The fusing point of glass 2 is 600~800 DEG C.

In the present invention, by the use of the successively compound dielectric layer 1 and dielectric layer 2, can make substrate, dielectric layer, Resistance alloys layer more preferably carries out the matching of thermal expansivity, enhance while increasing substrate insulating properties mutual bond strength and Stability.

Preferably, the glass 1 is devitrified glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃。

Preferably, the glass 2 is devitrified glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃-Bi₂O₃。

The material of the thermal insulation layer can be used having for row industry routine and insulate and thermally conductive material.

The material of the insulated thermal insulating layer can be the material with insulated heat effect of row industry routine.

Insulated thermal insulating layer and thermal insulation layer are applied by being arranged in the top and bottom of heater, can further be promoted and be added The thermal conversion efficiency of heater.

Thickness between each layer can be adjusted as needed, it is preferable that dielectric layer 1 is with a thickness of 80 μm~140 μm；Medium Layer 2 is with a thickness of 50 μm~80 μm.

The present invention also provides the preparation sides of the doped graphene alloy heat generating film heater of the stainless base steel described in one kind Method, comprising the following steps:

Step 1: stainless steel substrate surface is pre-processed；

Step 2: solvent, thickener, thixotropic agent, surfactant, binder are mixed, organic carrier is obtained；

Step 3: glass 1, glass 2 are mixed with organic carrier respectively, respectively obtain dielectric paste 1 and dielectric paste 2；

Step 4: dielectric paste 1 is compounded in a plane of pretreated stainless steel substrate, dry, sintering, In The dielectric layer 1 is formed on stainless steel substrate；Then the surface recombination dielectric paste 2 of dielectric layer 1, drying, sintering are being situated between again 1 surface of matter layer forms the dielectric layer 2；

Step 5: alloyed powder, Graphene powder, glass powder are mixed, the graphene/lowpriced metal alloy conduction material is obtained Material；

Step 6: mixing organic carrier is prepared into the graphene/lowpriced metal alloy conductive material and step 2, Obtain the doped graphene resistance alloys slurry；

Step 7: doped graphene resistance alloys slurry is compounded on the dielectric layer 2 in step 4, dry, sintering, In The resistance alloys layer is formed on dielectric layer 2 (present invention is also referred to as heating layer)；

Step 8: the resistance alloys layer that step 7 is obtained sprays one layer of insulated heat slurry；Compound Jie of stainless steel substrate The opposite face of matter layer 1 sprays one layer of insulating heat-conductive slurry, dry, obtains the doped graphene alloy heat generating of the stainless base steel Film heater.

The stainless steel substrate is a kind of in 430,304,316.

In the preparation method, the organic carrier includes mixed solvent, thickener, thixotropic agent, surfactant, glues Tie agent；Wherein, the mass parts ratio of solvent, thickener, thixotropic agent, surfactant and binder is 85-93: 8-14: 1-4: 1-4:1-8；The mixed solvent is terpinol, butyl acetate, a kind of or more in dibutyl phthalate Kind.

The glass powder 1 is devitrified glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃, glass powder 2 is crystallite Glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃-Bi₂O₃。

Preferably, the glass 2 of the graphene/lowpriced metal alloy conductive material glass powder and dielectric layer 2 is Identical material.

The sintering process of dielectric layer 1 described in step 4 are as follows: in air, arrived with 2 DEG C/min~10 DEG C/min heating rate 300 DEG C~500 DEG C, 1h~5h is kept the temperature, then with 0.5 DEG C/min~10 DEG C/min heating rate to 800 DEG C~1000 DEG C, heat preservation 1h~5h.

2 sintering process of dielectric layer are as follows: in air, with 2 DEG C/min~10 DEG C/min heating rate to 300 DEG C~500 DEG C, 1h~5h is kept the temperature, then with 0.5 DEG C/min~10 DEG C/min heating rate to 600 DEG C~800 DEG C, keeps the temperature 1h~5h.

Alloyed powder described in step 5 is one or more in NiB, NiCu, NiFe, NiAlCr.

Graphene described in step 5 is multi-layer graphene, with a thickness of 1nm~100nm.

As mass fraction, alloyed powder 45%~90%, graphene 1%~10%, glass powder 1%~15% have airborne Body 10%~30%.

Resistance alloys layer described in step 7 be sintered sintering process are as follows: vacuum degree be 10^-4~10^-3In Pa vacuum, with 2 DEG C/ Min~10 DEG C/min heating rate keeps the temperature 0.5h~2h, then with 0.5 DEG C/min~10 DEG C/min liter to 300 DEG C~500 DEG C Warm rate keeps the temperature 0.5h~3h to 600 DEG C~800 DEG C.

A kind of doped graphene alloy heat generating film heater of preferred stainless base steel of the present invention, preparation method include Following steps:

Step 1: stainless steel substrate surface is subjected to blasting treatment.

Step 2: by mixed solvent, thickener, thixotropic agent, surfactant, binder be uniformly mixed be made have it is airborne Body.

Step 3: glass powder 1, glass powder 2 are uniformly mixed to get with deployed organic carrier respectively dielectric paste 1, Dielectric paste 2.

Step 4: dielectric paste 1, dielectric paste 2 are taken up in order of priority by silk-screen printing and are imprinted on pretreated stainless steel Dry on substrate, sintering obtains the stainless steel substrate with insulating layer.

Step 5: alloyed powder, Graphene powder, glass powder 2 are uniformly mixed to get mixed powder.

Step 6: doping stone is uniformly mixed to get by organic carrier is prepared into mixed powder and step 2 that step 5 obtains Black alkene resistance alloys slurry.

Step 7: doped graphene resistance alloys slurry is imprinted in step 4 by certain circuit pattern by silk-screen printing Stainless steel substrate on, dry, sintering obtains stainless base steel heating layer.

Step 8: the compound coating surface of the stainless steel that step 7 is obtained sprays one layer of insulated heat slurry, back side spraying One layer of insulating heat-conductive slurry is dried to obtain a kind of doped graphene alloy heat generating film heater of stainless base steel.

The present invention also provides the application of the heater described in one kind, the application includes being applied in permanent lod.

Beneficial effects of the present invention:

(1) of the invention since function mutually uses lowpriced metal alloy (NiB series), electric conductivity and conductive noble metal difference are not Greatly, to replace noble metal membrane material, since alloy melting point is lower than the sintering temperature of single metal, to reduce heating film sintering Temperature greatly reduces material and preparation cost.

(2) present invention is mixed with graphene in resistance alloys slurry, increases the electric conductivity of heating film, accelerates and adds Thermal velocity, while the mechanical performance of film layer is also increased, enhance heating film and dielectric layer binding force, and make its heat shock resistance Performance also greatly improves.

(3) present invention employs the devitrified glasses with different gradient fusing points as stainless steel substrate compound medium layer, increases The insulation performance for adding substrate stainless steel, reduces that substrate, dielectric layer, matched coefficients of thermal expansion is poor between resistive layer three asks Topic, improves the binding force between three, while improving the thermal shock resistance and heater element security performance of heating film.

The resistivity of heater of the present invention reaches as high as 2.04 × 10-6 Ω m, compared to not using the present invention The structure and the electrically conductive composition case, lift up to 27.8 times；

The insulation resistance of heater of the present invention reaches as high as 8G Ω, compared to not using the structure of the invention And the case of the electrically conductive composition, lift up to 167%；

The heating rate of heater of the present invention reaches as high as 50 DEG C/s, compared to not using the knot of the invention The case of structure and the electrically conductive composition, lifts up to 116%；

The thermal shock resistance resistance varying-ratio of heater of the present invention is minimum up to 1%, compared to not using this The structure of invention and the case of the electrically conductive composition reduce up to 15 times；

Bond strength between each layer of heater of the present invention is I grade, compared to do not use it is of the invention described in The case of structure and the electrically conductive composition improves 2 ranks；

Detailed description of the invention

Attached drawing 1 is the preparation flow figure of stainless steel substrate compound medium layer of the present invention

Attached drawing 2 is a kind of preparation flow figure of the doped graphene alloy heat generating film heater of stainless base steel of the present invention

Attached drawing 3 is a kind of structural schematic diagram of the doped graphene alloy heat generating film heater of stainless base steel of the present invention；

In Fig. 3,1: insulated thermal insulating layer, 2: resistance alloys layer, 3: dielectric layer 2,4: dielectric layer 1,5: stainless steel substrate, 6: absolutely Edge heat-conducting layer.

Specific embodiment

Following embodiment is implemented by aforesaid operations method:

Stainless steel substrate compound medium layer uses preparation flow shown in FIG. 1 in following embodiment.

Heating film heating-body uses preparation flow shown in Fig. 2 in following embodiment.

The graphene is multi-layer graphene, with a thickness of 1nm~100nm.

The devitrified glass 1 is devitrified glass, solid-phase component SiO₂-Al₂O₃-CaO-MgO-B₂O₃；Fusing point be 800~ 1000℃；

2 solid-phase component of devitrified glass is SiO₂-Al₂O₃-CaO-MgO-B₂O₃-Bi₂O₃；Fusing point is 600 DEG C~800 ℃；

Insulated heat coating is obtained using existing Conventional insulation insulating moulding coating, and the insulated heat coating is, for example, Guangzhou Also take in the fresh material Science and Technology Ltd. offer the CN-302A trade mark material；

Insulating heat-conductive coating is obtained using existing Conventional insulation heat-conductive coating, and the insulating heat-conductive coating is, for example, Guangzhou Also take in the fresh material Science and Technology Ltd. offer the CN-202A trade mark material.

The heater is made by structural schematic diagram described in Fig. 3 in following embodiment；As shown in Figure 1, the hair Hot body includes stainless steel base 5, and two opposite planes are compounded with thermal insulation layer 6 and dielectric layer 1 (4) respectively；Dielectric layer 1 (4) surface recombination has dielectric layer 2 (3)；Dielectric layer 2 (3) surface recombination has resistance alloys layer 2；2 surface recombination of resistance alloys layer has Insulated thermal insulating layer 1.