阅读说明：本技术 一种石墨烯导电氧化铝陶瓷的制备方法 (A kind of preparation method of graphene conductive aluminium oxide ceramics ) 是由 贺祖章 张燕萍 赵志国 于 2019-08-12 设计创作，主要内容包括：本发明提供一种石墨烯导电氧化铝陶瓷的制备方法,利用了石墨烯材料的物理化学稳定性、独特的片层结构及优良的导电性能改善了氧化铝陶瓷的强度韧性,赋予了氧化铝陶瓷的导电功能；本发明属于无机功能性复合材料领域,其制备方法为：(1)石墨烯在液体硅凝胶中的分散；(2)氧化铝粉体的配合、表面处理及干燥；(3)分散有石墨烯的硅凝胶与经过配合和表面处理过的氧化铝粉体的均匀混合；(4)第(3)步中混好的物料的成型和热模压硫化及产品尺寸修整；(5)初步热压裂解第(4)中成型硫化好的产品；(6)真空高温烧结初步裂解后的产品,最终得到致密性好、力学性能优异、具有导电性能的氧化铝陶瓷材料产品。(The present invention provides a kind of preparation method of graphene conductive aluminium oxide ceramics, physical and chemical stability, unique lamellar structure and the excellent electric conductivity that grapheme material is utilized improve the strength and toughness of aluminium oxide ceramics, impart the conducting function of aluminium oxide ceramics；The invention belongs to inorganic functional field of compound material, preparation methods are as follows: (1) dispersion of the graphene in liquid silicone gel；(2) cooperation, surface treatment and drying of alumina powder；(3) Silica hydrogel for being dispersed with graphene is mixed with by cooperation and the uniform of surface-treated alumina powder；The molding and hot moulding vulcanization of mixed material and product size finishing in (4) (3) steps；(5) the good product of molding sulfuration in preliminary hot pressing cracking (4)；(6) product after vacuum high-temperature sintering tentatively cracks, finally obtain good compactness, excellent in mechanical performance, it is conductive can alumina ceramic material product.)

1. a kind of preparation method of graphene conductive aluminium oxide ceramics, it is characterised in that: specific step is as follows:

Step 1: dispersing graphene in liquid silicone gel；

Step 2: alumina powder is carried out cooperation processing, surface treatment and drying process；

Step 3: will be dispersed in the Silica hydrogel and step 2 of graphene that treated in step 1, alumina powder is uniformly mixed It closes；

Step 4: material mixed in step 3 is formed, hot-press vulcanization and product size finishing processing；

Step 5: the product that preliminary hot pressing cleavage step four is prepared；

Step 6: the product pressure less high temperature ceramic after hot pressing cracking in step 5 is sintered under vacuum condition, finally obtain stone Black alkene conducting aluminium oxide ceramic material product.

2. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 1 Described in liquid silicone gel be viscosity within the scope of 500-3000Mpas, two-component 1:1 mixing, needle penetration >=150mm, Add-on type Silica hydrogel of the room temperature operable time in 10-15hrs.

3. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 1 Described in graphene requirement: the number of plies≤5 layer, stack thickness < 10nm；Temperature is 25 DEG C, when humidity is 50%, according to GB/T- 24521-2009 standard testing, the graphene powder volume resistivity under 20-30MPa pressure≤1.0*10^-3Ω·cm。

4. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 1 Described in graphene dispersion in liquid silicone gel, specifically by graphene powder with the ultrasonic power of 1KW, keep system temperature 30 DEG C of conditions of < are spent, ultrasonic disperse 2hrs in liquid silicone gel is added to --- 4hrs；Wherein: the graphene and liquid silicon Gel is in mass ratio are as follows: graphene: liquid silicone gel=1:5-12.5.

5. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 2 Described in alumina powder refer to α crystal content >=99%, ball-aluminium oxide of the particle size distribution range in 0.1um -70um.

6. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 2 Described in alumina powder carry out cooperation processing, surface treatment and be dried refer to: by the powder of no less than 3 kinds different-grain diameters Body accumulate and mixed with planetary-type mixer by horsfield dense packing theory, with spraying shape in mixed process Formula is sprayed to mixed powder surface for the silane coupling agent for being free of N, P, S element in 98% ethanol solution is scattered in, then It is dry under the conditions of 50-80 DEG C.

7. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 3 It is middle by the alumina powder that is dispersed in the Silica hydrogel and step 2 of graphene that treated in step 1 in the ratio of 1:10-22 Uniformly mixing, the uniform mixing are the rates in vacuum kneader with 45-55r/min, and vacuum degree < -0.08Mpa is mixed 50 DEG C of temperature < are closed, the condition mixing of 3-5hrs of incorporation time.

8. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 4 Described in material mixed in step 3 is carried out molding and hot-press vulcanization refer to: the material mixed is placed in a setting In the mold of shape, molding vulcanization 2hrs, the product ruler are carried out not less than 50Mpa condition not less than 200 DEG C, pressure with temperature Very little finishing is burr removal or the stamp of specific structure shape of the product after the completion of vulcanizing.

9. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step 5 Described in the product that is prepared of preliminary hot pressing cleavage step four refer to: by the intact product of size is set after vulcanization or after stamp In hot-pressed sintering furnace, product surface apply 100-150Mpa pressure, vacuum degree be less than-0.08Mpa, with 3-5 DEG C/ The heating rate of min is warming up to 600 DEG C, and 3-5hrs conditions of heat preservation carry out hot pressing cracking.

10. a kind of preparation method of graphene conductive aluminium oxide ceramics according to claim 1, it is characterised in that: step The product pressure less high temperature ceramic sintering after hot pressing cracking in step 5 is referred under vacuum condition described in six: the first step is split Product after solution removes impressed pressure, and vacuum degree is maintained to be less than 0.08Mpa, and 1500-1800 DEG C of condition is selected to carry out ceramic Sintering, can finally be made the alumina ceramic material of different electric conductivities.

Technical field

The present invention provides a kind of preparation methods of graphene conductive aluminium oxide ceramics, belong to complex function ceramic material neck Domain.

Background technique

Graphene is a kind of excellent new material for obtaining promise prize in recent years, it is the hexagon two formed by single layer of carbon atom The nano novel material of honeycomb crystal lattice structure is tieed up, unique microstructure imparts its unconventional physicochemical properties, object Manage characteristic, mechanical property: Young's modulus reaches 1.0TPa, intrinsic tensile strength 130GPa；Thermal property: flawless graphene is led Hot coefficient is up to 5300W/ (mK), surmounts the high-melting-point of existing known materials, and some researches show that its fusing points to be up to 5000K is the only choosing as heat-resisting material；Electric property: the superior electron mobility being hardly affected by temperature is high Up to 15000cm²/ (Vs), electric conductivity is excellent, and just has quantum hall effect at room temperature；Optical property: mono-layer graphite Absorptivity of the alkene in wider wave-length coverage is only 2.3%, and the number of plies increases, and every layer of absorptivity can all increase about 2.3%, so The graphene of single layer or a small number of layers is pellucidity；Dissolution properties: have in nonpolarity or weak polar solvent good molten Xie Xing has super-hydrophobicity and excellent lipophilicity.Oxidisability: chemical property can be reacted with active metal；Reproducibility: can be Normal temperature and pressure state being oxidized property acid oxidase, obtains the graphene oxide for being dissolved in water；Addition reaction: graphene can be with H₂Added The graphite alkane with semiconductor property is prepared at reaction；Other spies for also having biocompatibility, high-temperature stability etc. excellent Property.

Aluminium oxide ceramics is one kind with Al₂O₃Based on ceramic material, the aluminium oxide ceramics of commercialization is according to Al₂O₃Content Usually have the kinds such as " 99 porcelain ", " 95 porcelain ", " 90 porcelain " " 85 porcelain ", the biggest advantage of aluminium oxide ceramics is: hardness height (is only second to Diamond), wear-resisting property is good, the small (3.5-4.0g/cm of density³, for most metal materials), excellent insulation performance (14-16MV/m), manufacturing process is mature and stable, cost performance is also relatively high；The aluminium oxide ceramics of commercialization is widely used, can not Or it lacks.

Conductivity ceramics refers to that (temperature, pressure etc.) under certain condition has electronics (or hole) conductance or ionic conductance Ceramic material has known that there are many high-temperature electric conduction ceramic materials: SiC base, MoSi₂Base, ZrO base, ThO₂Base, SrCeO₃Base etc..It is multiple One of phase material is based on fluorite type fast ion conducting material, by adding a certain amount of noble metal, such as Ag, Au and Electronic conductor oxide forms the two-phase mixed conductor material of continuous second phase in the material.The conductor material is mainly used in Electrode material, lambda sensor and oxygen permeable film material of SOFC etc., this complex phase mixed conductor material, which removes, requires material using item Have outside good heat chemistry and mechanical stability under part, also requiring two-phase is each other chemical inertness, but its production is difficult And its high cost limits its application development.

Summary of the invention

Because of the excellent properties and high performance-price ratio of conventional aluminium oxide ceramic material, for the application surface for widening aluminium oxide ceramics, institute It is that tradition height is assigned under the premise of not reducing aluminium oxide ceramics other aspects performance substantially absolutely with the problem to be solved in the present invention Edge alumina ceramic material electric conductivity, improves its economic value, widens its application surface.Thus the present invention provides a kind of graphite The preparation method of alkene conducting aluminium oxide ceramics, has been related to the wet dispersion technology of graphene, spherical inorganic powder material is most Closs packing and process for treating surface, the high temperature sintering technique etc. of ceramic material, by the electric conductivity of graphene and in hot conditions Under physical stability impart final product have conductive capability and good mechanical property.

Present invention utilizes the excellent conductive capabilities of graphene, are scattered in liquid silastic, then with activity Alumina powder progress is compound, and after high temperature sintering, a small amount of residue and graphene uniform of liquid silicone gel cracking are distributed in this In aluminium oxide ceramics, become the conductor phase of the ceramic material, because containing the electronics that largely can move freely in graphene, thus It imparts the aluminium oxide ceramics and is just provided with conductive capability under the conditions of atmospheric pressure at room.

The technical scheme is that a kind of preparation method of graphene conductive aluminium oxide ceramics, the specific steps are as follows:

Step 1: dispersing graphene in liquid silicone gel；

Step 2: alumina powder is carried out cooperation processing, surface treatment and drying process；

Step 3: will be dispersed in the Silica hydrogel and step 2 of graphene that treated in step 1, alumina powder is uniform Mixing；

Step 4: material mixed in step 3 is formed, hot-press vulcanization and product size finishing processing；

Step 5: the product that preliminary hot pressing cleavage step four is prepared；

Step 6: be sintered the product pressure less high temperature ceramic after hot pressing cracking in step 5 under vacuum condition, final To excellent in mechanical performance, the graphene conductive alumina ceramic material product of conductive energy.

Further, graphene feature described in step 1 are as follows: powder state, lamellar structure, the number of plies≤5 layer stack Thickness < 10nm；Temperature is 25 DEG C, when humidity is 50%, according to GB/T-24521-2009 standard testing, the graphene powder body Product resistivity under 20-30MPa pressure≤1.0*10^-3Ω·cm。

Further, liquid silicone gel feature described in step 1 are as follows: transparency liquid, viscosity is in 500-3000Mpa Within the scope of s, (wherein, two-component refers to: the Silica hydrogel is made of two parts A and B, and two parts do not use for two-component 1:1 mixing When be apart from, need to vulcanize under certain condition in use, mix in the ratio of 1:1), needle penetration >= 150mm, add-on type Silica hydrogel of the room temperature operable time in 10-15hrs.

Further, graphene dispersion described in step 1 is in liquid silicone gel, specifically by graphene powder with The ultrasonic power of 1KW keeps 30 DEG C of conditions of system temperature <, is added to ultrasonic disperse 2hrs in liquid silicone gel --- 4hrs； Wherein: the graphene and liquid silicone gel is in mass ratio are as follows: graphene: liquid silicone gel=1:5-12.5.

Further, alumina powder described in step 2 refers to that α crystal content >=99%, particle size distribution range exist The ball-aluminium oxide of 0.1um -70um.

Further, alumina powder described in step 2 carries out cooperation processing, surface treatment and is dried to refer to: The powder of no less than 3 kinds different-grain diameters accumulate and carried out with planetary-type mixer by horsfield dense packing theory It mixes, the silane coupling agent for being free of N, P, S element in 98% ethanol solution will be scattered in mixed process with Sprayable It is sprayed to mixed powder surface, it is then dry under the conditions of 50-80 DEG C.

It is preferred that three kinds of partial sizes, four kinds of partial sizes, the different types of ball-aluminium oxide powder of five kinds of partial sizes have carried out horsfield Dense packing theory carries out accumulation mixing.

It is preferred that two kinds of silane coupling agents of KH560, KH570 are surface-treated and are dried to the alumina powder mixed.

Further, the oxidation that will be dispersed in the Silica hydrogel and step 2 of graphene that treated in step 3 in step 1 Aluminium powder body is mixed by the ratio uniform of 1:10-22, and the uniform mixing is the speed in vacuum kneader with 45-55r/min Rate, 50 DEG C of vacuum degree <-0.08Mpa, mixing temperature <, the condition mixing of 3-5hrs of incorporation time.

It is preferred that graphene Silica hydrogel and alumina powder are respectively as follows: 1:10,1:13,1:16,1:19,1:22 in mass ratio Ratio carry out it is eligible under mixing.

Further, material mixed in step 3 is subjected to molding described in step 4 and hot-press vulcanization refers to: The material mixed is placed in the mold of certain shapes, is carried out not less than 200 DEG C, pressure not less than 50Mpa condition with temperature Molding vulcanization 2hrs, the product size finishing are burr removal or the specific structure of the product after the completion of vulcanizing The stamp of shape.

It is preferred that conditions of vulcanization are as follows: 200 DEG C/50Mpa/2hrs, 225 DEG C/50MPa/2hrs, 250 DEG C/50Mpa/2hrs, 200 DEG C/75MPa/2hrs, and 200 DEG C/100Mpa/2hrs, 225 DEG C/75Mpa/2hrs, 225 DEG C/100Mpa/2hrs, 250 DEG C/ 75Mpa/2hrs, 250 DEG C/100Mpa/2hrs.

Further, the product that preliminary hot pressing cleavage step four is prepared described in step 5 refers to: after vulcanization Or the intact product of size is placed in hot-pressed sintering furnace after stamp, applies the pressure of 100-150Mpa, vacuum degree in product surface Less than-0.08Mpa, 600 DEG C are warming up to the heating rate of 3-5 DEG C/min, 3-5hrs conditions of heat preservation carry out hot pressing cracking.

Further, by the product pressure less high temperature ceramics after hot pressing cracking in step 5 under vacuum condition described in step 6 Change sintering to refer to: the product after the first step is cracked removes impressed pressure, and vacuum degree is maintained to be less than -0.08Mpa, and foundation is initially matched Fang Butong selects 1500-1800 DEG C of condition to carry out ceramic sintering, and the aluminium oxide ceramics of different electric conductivities can finally be made Material.

Graphene is dispersed in liquid silicone gel well by high frequency ultrasound dispersing technology, solves stone by the present invention The problem of black alkene is easy to reunite, difficult dispersion, then, the alumina powder that the liquid silicone gel containing graphene and dense packing activated Body (i.e. processed by silane coupling agent) is uniformly mixed under the mixing of vacuum strong stirring, prepares the mixing with plasticity Material, vulcanized by hot press moulding, graphene be further scattered in vulcanization after prefabricated blank in, due to graphene additive amount and its The presence of free electron, has gone beyond conductivity threshold, to impart the conductive capability of preform blank after vulcanization, further vacuum Pintsch process and vacuum high-temperature sintering ,-H ,-CH in Silica hydrogel₃Group is quickly removed, and graphene chemical stability makes it It is almost not involved in cracking reaction, so that the electric conductivity of the pre-sintered body in step 4 is maintained, in subsequent step 5 In high-temperature sintering process, recrystallized between graphene-Silica hydrogel cracking residue-alumina molecule, crystal grain is grown up, gap (stomata) It is gradually reduced with crystal boundary, by the transmitting of substance, green body total volume is shunk, and density increases, and finally becoming has certain micro- knot The dense multicrystalline sintered body of structure, by the invention it is possible to prepare the excellent oxidation of the electric conductivity not limited by temperature condition Aluminium ceramic material.

The beneficial effects of the present invention are:

(1) it is mixed with using a small amount of graphene-Silica hydrogel compound with the alumina powder that dense packing activated Plastic, electric conductivity material is provided, so that the molding of some shaped pieces, Complex Parts becomes simple.

(2) method that Pintsch process organic matter precursor prepares functionality ceramic is utilized, has broken the system of traditional ceramics Standby technique；And the disadvantages of process of traditional handicraft is more, length is time-consuming, prefabricated blank intensity difference, has also obtained good improvement.Pass through elder generation High temperature pressure cracking, then the step of high temperature sintering overcome bubbling, cracking, micro-crack in organic cracking method preparation ceramics The disadvantages of Quick Extended, stress are concentrated, the doping of graphene and Silica hydrogel cracking residual mutually play the role of reinforcing and toughening, thus So that the alumina ceramic product that sintering comes out has the excellent performance such as hardness height, high intensity, super abrasive.

(3) the dispersion of graphene has obtained significantly improving, and the addition of minimal amount graphene allows for sintering and comes out Alumina ceramic product be provided with preferable conductive capability, and its electric conductivity in large temperature range (such as: room Temperature --- 1200 DEG C) it is unaffected, the application surface of alumina ceramic material has been widened, its economical and practical value is improved.

Specific embodiment

A kind of preparation preferably to explain the present invention, in conjunction with following specific embodiments to graphene conductive aluminium oxide ceramics Method is discussed further.But the present embodiment cannot be used for the limitation present invention, all using similar method and its phase of the invention Like variation, protection scope of the present invention should all be included in.