阅读说明：本技术 一种复合陶瓷材料及其制备方法 (Composite ceramic material and preparation method thereof ) 是由 刘建 王重海 路翔 齐刚 于淼 翟萍 廖荣 于 2021-09-07 设计创作，主要内容包括：本发明公开了一种复合陶瓷材料,由以下原料制备而成：石墨粉或碳粉、聚碳硅烷、助剂,以及氮化硅粉、氮化铝粉、硼化锆粉、硼化钛粉中的一种或者几种；所述助剂包括：氧化铝、氟化钙、氧化镍、氧化钇、氧化钙中的一种或者几种；本发明另一方面公开了一种复合陶瓷材料制备方法,能够实现陶复合瓷材料具有抗氧化性、高导热性,能够代替石墨材料在600-1000℃使用,且在≤800℃的工作环境下不会出现石墨氧化现象。(The invention discloses a composite ceramic material which is prepared from the following raw materials: graphite powder or carbon powder, polycarbosilane, an auxiliary agent and one or more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder; the auxiliary agent comprises: one or more of aluminum oxide, calcium fluoride, nickel oxide, yttrium oxide and calcium oxide; the invention also discloses a preparation method of the composite ceramic material, which can realize the oxidation resistance and high thermal conductivity of the ceramic composite ceramic material, can replace the graphite material to be used at the temperature of 600-1000 ℃, and can not generate the graphite oxidation phenomenon under the working environment of less than or equal to 800 ℃.)

1. the composite ceramic material is characterized by being prepared from the following raw materials:

graphite powder or carbon powder, polycarbosilane, an auxiliary agent and one or more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder;

the auxiliary agent comprises: one or more of aluminum oxide, calcium fluoride, yttrium oxide, calcium oxide and silicon carbide.

2. The composite ceramic material of claim 1, wherein the composite ceramic material has a thermal conductivity of 35-60W/m.k (25 ℃).

3. The composite ceramic material according to claim 1, wherein graphite powder or carbon powder accounts for 10-30 wt% of the total mass of the solid raw material.

4. The preparation method of the composite ceramic material is characterized by comprising the following steps of:

the raw materials comprise graphite powder or carbon powder and one or a mixture of more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder;

adding the mixture, an auxiliary agent, a dispersing agent and polycarbosilane into equipment for mixing to obtain ceramic slurry;

drying the ceramic slurry to obtain ceramic powder;

prepressing and molding the ceramic powder to obtain a ceramic blank;

and sintering the ceramic blank to obtain the ceramic material.

5. The preparation method of the composite ceramic material according to claim 4, wherein the mixture is added in the following proportion:

the graphite powder or the carbon powder accounts for 10-30 wt% of the total solid raw material, the silicon nitride powder accounts for 40-70 wt% of the total solid raw material, and the aluminum nitride powder accounts for 10-20 wt% of the total solid raw material;

or

The graphite powder or the carbon powder accounts for 10-30 wt% of the total solid raw material, the zirconium boride powder accounts for 30-40 wt% of the total solid raw material, and the aluminum nitride powder accounts for 10-30 wt% of the total solid raw material; the titanium boride powder accounts for 10-30 wt% of the total solid raw material.

6. The method for preparing a composite ceramic material according to claim 5, wherein the auxiliary agent comprises: one or more of aluminum oxide, calcium fluoride, yttrium oxide, calcium oxide and silicon carbide;

the adding mass of the aluminum oxide, the calcium fluoride, the yttrium oxide, the calcium oxide and the silicon carbide is respectively 0-20 wt%, 0-10 wt%, 0-26.7 wt%, 0-20 wt% and 0-28 wt% of the adding mass of the graphite powder or the carbon powder.

7. The preparation method of the composite ceramic material as claimed in claim 5, wherein the addition mass of the polycarbosilane is 5-10 wt% of the addition mass of the graphite powder or the carbon powder.

8. The method for preparing a composite ceramic material according to claim 5, wherein the dispersant is absolute ethanol;

when the ceramic slurry is dried, vacuum drying is adopted, the drying temperature is 60-80 ℃, the drying time is 12-14 hours, and the content of absolute ethyl alcohol in the ceramic powder is less than 2 wt%.

9. The method for preparing composite ceramic material according to claim 4, wherein the pressure of the ceramic powder is 400-800kg/cm³。

10. The preparation method of the composite ceramic material according to claim 4, wherein the sintering process of the ceramic body is as follows:

heating to 500 deg.C for 28-32 min; 500 ℃ and 1000 ℃, and the temperature rise time is 68-72 min; at temperature of 1000 ℃ and 1400 ℃, the temperature rise time is 68-72min, the heat preservation time is 58-62min, and the pressurization is started when the temperature reaches 1400 ℃; 1400 ℃ and 1760 ℃, the temperature rise time is 68-72min, and the heat preservation time is 58-62 min;

or

Heating to 500 deg.C for 28-32 min; 500 ℃ and 1000 ℃, and the temperature rise time is 68-72 min; at temperature of 1000 ℃ and 1400 ℃, the temperature rise time is 48-52min, the heat preservation time is 13-17min, and pressurization is started when the temperature reaches 1400 ℃; 1400 ℃ and 1900 ℃, the temperature rise time is 68-72min, and the heat preservation time is 60 min;

the pressurizing pressure is 2MPa or 22 MPa.

Technical Field

The invention relates to the field of oxidation-resistant and high-thermal-conductivity composite ceramic materials, in particular to the field of metal thermal coupling molds.

Background

The graphite has better stability in nature at normal temperature, has excellent high-temperature mechanical property, corrosion resistance, heat conductivity and other characteristics, and is widely applied to the fields of metallurgy, electricity, electrochemistry and the like; however, as the temperature rises to 400 ℃, some active site sites in the graphite structure are susceptible to corrosive gases (O)₂、NH₃Etc.) to undergo a chemical reaction; in an aerobic environment higher than 400 ℃, oxidation occurs, the oxidation rate is sharply accelerated along with the temperature rise, the strength of the material is greatly reduced or even disappears, and the application of the graphite material in the aerobic condition is greatly limited. Particularly, with the continuous development of the electronic industry technology, the industries such as newly-emerging new energy electric automobiles, 3D mobile phone screens and the like all use graphite mold materials, the working temperature is usually 600-; for this reason, the solution of improving the high-temperature oxidation resistance of graphite materials and maintaining high thermal conductivity of the materials has been sought for many years.

Disclosure of Invention

The invention aims to realize that the ceramic composite material has oxidation resistance and high thermal conductivity, can replace graphite materials, and does not have the phenomenon of graphite oxidation under the working environment of less than or equal to 800 ℃; the composite ceramic material is prepared from the following materials: graphite powder or carbon powder, polycarbosilane, an auxiliary agent and one or more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder; the oxidation resistance of the composite material is realized, and the heat conducting property of the composite material can be improved.

In order to achieve the purpose, the technical scheme of the invention is as follows:

according to one aspect of the invention, the composite ceramic material is prepared from the following raw materials: graphite powder or carbon powder, polycarbosilane, an auxiliary agent and one or more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder; the auxiliary agent comprises: one or more of aluminum oxide, calcium fluoride, yttrium oxide, calcium oxide and silicon carbide;

the composite ceramic material is not oxidized within 3 hours in the use environment at the temperature of less than or equal to 800 ℃;

the composite material has an oxidation rate of 0 at 800 ℃, an oxidation rate of less than or equal to 0.12 wt% at 1000 ℃, and an oxidation rate of less than or equal to 0.03 wt% at 900 ℃; the detection method of the oxidation rate of the composite material comprises the following steps: drying and weighing the composite ceramic sample and measuring the data as W₀Putting the ceramic powder into a muffle furnace with corresponding temperature, preserving heat for 3 hours, taking out a composite ceramic sample, weighing W_yOxidation rate ═ W₀-W_y)/W₀100% of the total weight; the density of the composite ceramic composite material is more than 93 percent; bending strength is 80-800 Mpa; the hardness is 0.4-12 Gpa; resistivity of 2.0-20 [ mu ] omega m; the use temperature is 600-1000 ℃.

The beneficial effect of the present invention over the prior art is that,

1. the raw materials prepared from the composite ceramic material comprise one or more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder, and form a glass state dispersed around graphite or carbon for wrapping in the sintering process, so that macroscopic and microscopic defects between the graphite and other phases are reduced;

2. because graphite or carbon is not easy to sinter in ceramics and is not beneficial to being combined with ceramic materials, gaps around the graphite or carbon phase are further filled by adding polycarbosilane, and the polycarbosilane has good affinity with glass phases formed when the graphite or carbon and other materials are sintered; finally, crystal phase defects or cracks in the composite material are reduced, so that the composite material has good heat-conducting property;

3. in the using process, when the composite material is in a high-temperature environment, silicon nitride, aluminum nitride, zirconium boride and titanium boride can form metal oxide, so that not only is the oxidation of oxygen on graphite or carbon avoided, but also the metal oxide is further attached to or even wrapped around the graphite or carbon, and the oxidation or corrosion of the graphite or carbon is avoided; the metal oxide has high heat resistance, is not volatilized, melted or damaged at high temperature, and can still protect graphite or carbon at high temperature so as to avoid corrosion at high temperature.

Relatively common B₄When C and other materials are mixed and sintered with graphite powder or carbon powder, the C and other materials can be oxidized into B at a certain temperature₂O₃，B₂O₃Will be coated on the surface of the easily oxidized component and has antioxidant effect at a certain temperature, but B₂O₃Is a volatile material, especially at temperatures above 850 ℃, mainly due to B₂O₃The increased volatility of (a) causes the oxidation rate of the composite material to begin to increase;

the material reasonably designs a composite material framework, a microstructure and a sintering mechanism, so that high-temperature and rapid sintering can be realized; the densification of the composite material is facilitated, so that the high thermal conductivity of the composite ceramic is facilitated;

therefore, the composite ceramic material is not oxidized in the service environment of less than or equal to 800 ℃ for 3 hours, and the oxidation rate of less than or equal to 0.12 wt% at 1000 ℃; the corrosion resistance of the graphite material is obviously improved, the heat conductivity is still good, the good stability of the graphite and the non-wettability to metal are kept, and the graphite material can be replaced to be used in the high-temperature field.

Further, the thermal conductivity of the composite ceramic material is 35-60W/m.k (25 ℃).

The further technical scheme has the beneficial effects that the thermal conductivity of the composite ceramic material is 35-60W/m.k (25 ℃), the composite ceramic material can be used as a material of a metal hot-press forming grinding tool instead of a graphite material, the composite ceramic material has high thermal conductivity, and heat can be transferred to a molded product through a composite material die.

Further, graphite powder or carbon powder accounts for 10-30 wt% of the total mass of the solid raw materials.

The further technical scheme has the beneficial effects that the graphite or the carbon has better stability, excellent high-temperature mechanical property and metal non-wettability, so that the composite ceramic material has high graphite addition amount, the high-temperature mechanical property and the metal non-wettability are better, but the graphite is difficult to sinter in the ceramic, and the composite ceramic is easy to have poor strength and thermal conductivity; therefore, graphite powder or carbon powder accounting for 10-30 wt% of the total mass of the solid raw materials is a preferable scheme.

According to another aspect of the present invention, there is provided a method for preparing a composite ceramic material, comprising the steps of: the raw materials comprise graphite powder or carbon powder and one or more of silicon nitride powder, aluminum nitride powder, zirconium boride powder and titanium boride powder which are mixed to obtain a mixture; adding the mixture, an auxiliary agent, a dispersing agent and polycarbosilane into equipment for mixing to obtain ceramic slurry; drying the ceramic slurry to obtain ceramic powder; prepressing and molding the ceramic powder to obtain a ceramic blank; sintering the ceramic blank to obtain the ceramic material; adding a preferential additive into a dispersing agent for premixing for 2-4 hours, and then adding the mixture into the premixed material for mixing for 6-10 hours; further preferably, the graphite powder or carbon powder has a size of D50: 1-5 μm; the size of the silicon nitride powder is D50: <1 μm; the size of the zirconium boride powder is D50: 1-3 μm.

Compared with the prior art, the invention has the advantages that the material reasonably designs the composite material framework, the microstructure and the sintering mechanism, thereby realizing high-temperature and rapid sintering; the densification of the composite material is facilitated, so that the high thermal conductivity of the composite ceramic is facilitated;

after the ceramic slurry is dried, the ceramic blank is prepared by pre-pressing and forming, so that the density of the biscuit can be improved, the furnace charging yield is increased, the cost is saved, the densification of the sintered composite material is facilitated, and the thermal conductivity is improved;

therefore, the composite ceramic material is not oxidized in the service environment of less than or equal to 800 ℃ for 3 hours, and the oxidation rate of less than or equal to 0.12 wt% at 1000 ℃; the oxidation resistance of the graphite material is obviously improved, the graphite material still has good thermal conductivity, and meanwhile, the good stability of the graphite and the non-wettability to metal are kept, so that the graphite material can be used in the field of higher temperature instead of the graphite material.

Further, the mixture is added in the proportion that: the graphite powder or the carbon powder accounts for 10-30 wt% of the total solid raw material, the silicon nitride powder accounts for 40-70 wt% of the total solid raw material, and the aluminum nitride powder accounts for 10-20 wt% of the total solid raw material; or the graphite powder or the carbon powder accounts for 10-30 wt% of the total solid raw material, the zirconium boride powder accounts for 30-40 wt% of the total solid raw material, and the aluminum nitride powder accounts for 10-30 wt% of the total solid raw material; the titanium boride powder accounts for 10-30 wt% of the total solid raw material.

The further technical scheme has the advantages that the density of the composite material is gradually reduced along with the increase of the addition amount of the graphite; the heat conductivity coefficient is a trend that the heat conductivity coefficient is increased and then decreased along with the increase of the addition amount; the material addition ratio thus achieves high thermal conductivity as well as high corrosion resistance.

Further, the auxiliary agent comprises: one or more of aluminum oxide, calcium fluoride, yttrium oxide, calcium oxide and silicon carbide; the adding mass of the aluminum oxide, the calcium fluoride, the yttrium oxide, the calcium oxide and the silicon carbide is respectively 0-20 wt%, 0-10 wt%, 0-26.7 wt%, 0-20 wt% and 0-28 wt% of the adding mass of the graphite powder or the carbon powder.

The further technical scheme has the beneficial effects that the auxiliary agent is beneficial to material sintering and densification, and after sintering, partial or all auxiliary agent volatilization and other phenomena caused by high temperature can not occur in the high-temperature environment, so that internal defects can not occur, and the oxidation resistance and high thermal conductivity of the composite material can not be reduced.

Further, the adding mass of the polycarbosilane is 5-10 wt% of the adding mass of the graphite powder or the carbon powder.

The further technical scheme has the beneficial effects that by the addition proportion of the polycarbosilane, macroscopic and microscopic defects among phases caused by graphite or carbon powder can be effectively filled, and the compactness of the composite material is improved, so that the heat conductivity of the composite material is improved; and the strength of the composite material is prevented from being reduced when excessive addition is carried out.

Further, the dispersing agent is absolute ethyl alcohol; when the ceramic slurry is dried, vacuum drying is adopted, the drying temperature is 60-80 ℃, the drying time is 12-14 hours, and the absolute ethyl alcohol content of the ceramic powder is less than 2 wt%;

when the ceramic powder slurry is pre-pressed and formed, the pressure is 400-800kg/cm³。

The further technical scheme has the beneficial effects that the strength and the compactness of the green body prepared by subsequent prepressing are favorably realized by firstly drying the ceramic powder and ensuring that the absolute ethyl alcohol content of the ceramic powder is less than 2 wt%.

Further, the sintering process of the ceramic body comprises the following specific steps: heating to 500 deg.C for 28-32 min; 500 ℃ and 1000 ℃, and the temperature rise time is 68-72 min; at temperature of 1000 ℃ and 1400 ℃, the temperature rise time is 68-72min, the heat preservation time is 58-62min, and the pressurization is started when the temperature reaches 1400 ℃; 1400 ℃ and 1760 ℃, the temperature rise time is 68-72min, and the heat preservation time is 58-62 min; or heating to 500 deg.C for 28-32 min; 500 ℃ and 1000 ℃, and the temperature rise time is 68-72 min; at temperature of 1000 ℃ and 1400 ℃, the temperature rise time is 48-52min, the heat preservation time is 13-17min, and pressurization is started when the temperature reaches 1400 ℃; 1400 ℃ and 1900 ℃, the temperature rise time is 68-72min, and the heat preservation time is 60 min; the pressurizing pressure is 2MPa or 22 MPa.

The further technical scheme has the beneficial effects that the sintering temperature is adopted, so that the sintering is fast, the final sintering temperature is high, and the densification of the composite material is facilitated; and the temperature rise rate is controlled by adopting sectional temperature rise, so that the materials are heated uniformly, the reaction time among the components and the clearance time of gaps are ensured, the increase of cracks or crystal phase defects among phases, which are caused by the disadvantages when the ceramic components are combined with graphite, is avoided, and the high thermal conductivity of the composite ceramic material is finally realized.

Detailed Description

In order to better understand the technical solution of the present invention, the present invention is further described below with reference to specific examples.

Example 1:

in one aspect, the present invention provides a composite ceramic material, which is prepared from the following raw materials: graphite powder, polycarbosilane, an auxiliary agent, silicon nitride powder and aluminum nitride powder; the auxiliary agent comprises: alumina, calcium fluoride, yttrium oxide, calcium oxide; the graphite powder accounts for 22 wt% of the total mass of the solid raw materials; the composite ceramic material is not oxidized within 3 hours in the use environment at the temperature of less than or equal to 800 ℃; the composite material has an oxidation rate of 0 at 800 ℃, an oxidation rate of less than or equal to 0.12 wt% at 1000 ℃, and an oxidation rate of less than or equal to 0.03 wt% at 900 ℃; the detection method of the oxidation rate of the composite material comprises the following steps: drying and weighing the composite ceramic sample and measuring the data as W₀Putting the ceramic powder into a muffle furnace with corresponding temperature, preserving heat for 3 hours, taking out a composite ceramic sample, weighing W_yOxidation rate ═ W₀-W_y)/W₀100% of the total weight; the thermal conductivity of the composite ceramic material is 43W/m.k (25 ℃); the density is more than 93 percent; bending strength is 500 Mpa; the hardness is 5.2 Gpa; thermal conductivity 43W/m.k (25 ℃ C.); resistivity of 5.6 [ mu ] omega m; the use temperature is 600-1000 ℃.

Another aspect of the present disclosure provides a method for preparing a composite ceramic material, including the following steps: mixing 300g of graphite powder, 780g of silicon nitride powder and 150g of aluminum nitride powder to obtain a mixture; adding the auxiliary agent into the dispersing agent for premixing for 4 hours, and then adding the mixture and polycarbosilane into ball milling equipment for ball milling to obtain ceramic slurry; the adding mass of the polycarbosilane is 30 g; drying the ceramic slurry to obtain ceramic powder; prepressing and molding the ceramic powder to obtain a ceramic blank; sintering the ceramic blank to obtain the ceramic material; the auxiliary agent comprises: 30g of aluminum oxide, 30g of calcium fluoride, 60g of yttrium oxide and 10g of calcium oxide; the dispersing agent is absolute ethyl alcohol, and the addition amount of the absolute ethyl alcohol is 1500 ml; the ball milling time is 12 hours, the drying temperature of the ceramic slurry is 75 ℃, and the drying time is 13 hours; the content of absolute ethyl alcohol in the ceramic powder is 1.8 wt%;

prepressing the ceramic powder in a dry press, wherein the prepressing pressure is controlled at 800kg/cm³The prepressed ceramic body is processed according to the following systemAnd (3) sintering:

heating to 500 deg.C for 30 min; 500 ℃ and 1000 ℃, and the temperature rise time is 70 min; at the temperature of 1000 ℃ and 1400 ℃, the temperature rise time is 50min, the heat preservation time is 60min, and the pressurization is started when the temperature reaches 1400 ℃; 1400 ℃ and 1900 ℃, the temperature rise time is 70min, and the heat preservation time is 60 min;

the pressurization pressure is 2MPa and is realized by filling nitrogen.

Example 2:

the same features of this embodiment as those of embodiment 1 are not described again, and the different features of this embodiment from those of embodiment 1 are: in one aspect, the present invention provides a composite ceramic material, which is prepared from the following raw materials: graphite powder, polycarbosilane, an assistant, zirconium boride powder, aluminum nitride powder and titanium boride powder; the auxiliary agent comprises: yttrium oxide, aluminum oxide, silicon carbide; the graphite powder or the carbon powder accounts for 20.6 wt% of the total mass of the solid raw materials; the thermal conductivity of the composite ceramic material is 57W/m.k (25 ℃), and the bending strength is 290 Mpa; hardness 7 Gpa; the resistivity was 2.6. mu. omega. m.

Another aspect of the present disclosure provides a method for preparing a composite ceramic material, including the following steps: mixing 220g of graphite powder, 400g of zirconium boride powder, 150g of aluminum nitride powder and 150g of titanium boride powder to obtain a mixture; adding the auxiliary agent into the dispersing agent for premixing for 3 hours, and then adding the mixture and polycarbosilane into ball milling equipment for ball milling to obtain ceramic slurry; the adding mass of the polycarbosilane is 16 g; drying the ceramic slurry to obtain ceramic powder; prepressing and molding the ceramic powder to obtain a ceramic blank; sintering the ceramic blank to obtain the ceramic material; the auxiliary agent comprises: 30g of alumina, 58g of yttrium oxide and 60g of silicon carbide; the dispersing agent is absolute ethyl alcohol, and the addition amount of the absolute ethyl alcohol is 1300 ml; the ball milling time is 10 hours, the drying temperature of the ceramic slurry is 60-80 ℃, and the drying time is 13 hours; the content of absolute ethyl alcohol in the ceramic powder is 1.2 wt%;

the ceramic powder is pre-pressed in a dry press, the pre-pressing pressure is controlled at 500kg/cm3, and the pre-pressed ceramic blank is sintered according to the following system:

heating to 500 deg.C for 30 min; 500 ℃ and 1000 ℃, and the temperature rise time is 70 min; at the temperature of 1000 ℃ and 1400 ℃, the temperature rise time is 50min, the heat preservation time is 15min, and the pressurization is started when the temperature reaches 1400 ℃; 1400 ℃ and 1900 ℃, the temperature rise time is 70min, and the heat preservation time is 60 min; the pressurizing pressure is 22 MPa.

Example 3:

the same features of this embodiment as those of embodiment 1 are not described again, and the different features of this embodiment from those of embodiment 1 are: in one aspect, the present invention provides a composite ceramic material, which is prepared from the following raw materials: carbon powder, polycarbosilane, an auxiliary agent, silicon nitride powder and aluminum nitride powder; the auxiliary agent comprises: alumina, calcium fluoride, yttrium oxide, calcium oxide; the graphite powder or the carbon powder accounts for 20 wt% of the total mass of the solid raw materials; the thermal conductivity of the composite ceramic material is 35-60W/m.k (25 ℃).

Another aspect of the present disclosure provides a method for preparing a composite ceramic material, including the following steps: mixing 300g of carbon powder, 780g of silicon nitride powder and 150g of aluminum nitride powder to obtain a mixture; adding the auxiliary agent into a dispersing agent for premixing for 2 hours; the adding mass of the polycarbosilane is 15 g; the auxiliary agent comprises: 30g of aluminum oxide, 30g of calcium fluoride, 60g of yttrium oxide and 10g of calcium oxide; the dispersing agent is absolute ethyl alcohol, and the addition amount of the absolute ethyl alcohol is 1600 ml; the ball milling time is 10 hours, the drying temperature of the ceramic slurry is 60 ℃, and the drying time is 13 hours; the content of absolute ethyl alcohol in the ceramic powder is 1.2 wt%.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the features described above have similar functions to (but are not limited to) those disclosed in this application.

Comparative example:

1. comparative examples of the oxidation rates of the composite material of the present invention and graphite material at different temperatures are given in the following table:

the application discloses a comparison table of oxidation rates of composite materials at different oxidation temperatures:

2. the invention discloses a data table of the density and the thermal conductivity of a composite ceramic material under the condition that the addition amount of graphite is a single variable:

influence of graphite addition on the composite material:

the addition amount of the graphite is wt%	5	10	20	30	40
						Density (g/cm3)	2.737	2.690	2.650	2.582	2.085
Thermal conductivity (W/m.k)	25.21	47.36	62.8	53.36	38.66

3. The invention discloses a data table of the density of a composite ceramic material under the condition that the final firing temperature is a single variable:

influence of firing temperature on the composite: