阅读说明：本技术 一种玻璃碳体材料及其制备方法 (Glassy carbon material and preparation method thereof ) 是由 张壮飞 范静哲 沈维霞 房超 张跃文 王倩倩 陈良超 万彪 贾晓鹏 于 2021-01-20 设计创作，主要内容包括：本发明属于无机非金属材料领域,涉及一种玻璃碳体材料及其制备方法,具体是以纳米金刚石为前驱物,经真空放电等离子烧结得到所述玻璃碳体材料。本发明提供的玻璃碳体材料的制备方法,采用单一纳米金刚石材料作为前驱物,即可简单、快速、高效地制备得到玻璃碳体材料。(The invention belongs to the field of inorganic non-metallic materials, and relates to a glassy carbon material and a preparation method thereof, in particular to a glassy carbon material which is obtained by using nano diamond as a precursor and sintering the nano diamond by vacuum discharge plasma. The preparation method of the glassy carbon material provided by the invention adopts a single nano diamond material as a precursor, and the glassy carbon material can be simply, quickly and efficiently prepared.)

1. The preparation method of the glassy carbon material is characterized in that the glassy carbon material is prepared by taking nano diamond as a precursor and sintering the precursor by vacuum discharge plasma.

2. The method for preparing a glassy carbon material according to claim 1, wherein the spark plasma sintering is performed under vacuum by controlling the pressure to 30MPa, raising the temperature to 800 ℃ at a temperature raising rate of 100 ℃/min, and maintaining the temperature for 2 min; then the pressure is increased to 50-100MPa, the temperature is increased to 1400 ℃ at the heating rate of 100 ℃/min, and the temperature is kept for 5-10 min.

3. The method for preparing a vitreous carbon material according to claim 1 or 2, wherein the nano-diamond has a particle size of 5 to 50 nm.

4. The method for producing a vitreous carbon material according to claim 1 or 2, wherein said vacuum is a degree of vacuum lower than 10 Pa.

5. The method for preparing a glassy carbon material according to claim 1 or 2, wherein the nanodiamond is subjected to acid washing, alkali washing, deionized water washing in sequence before spark plasma sintering, and then vacuum drying treatment.

6. A vitreous carbon body material produced according to the method of any one of claims 1 to 5.

Technical Field

The invention belongs to the field of inorganic non-metallic materials, and relates to a glassy carbon material and a preparation method thereof.

Background

Glassy carbon is an amorphous and amorphous carbon material, has excellent properties such as good electrical conductivity, high chemical stability, small thermal expansion coefficient, hard texture, good air tightness and the like, and is widely applied in the field of electrochemical electrodes and semiconductor processing.

The traditional glassy carbon is prepared by carrying out high-temperature heat treatment on an organic resin material by vacuum inert gas, the process is complex and long in period, the core essence of the glassy carbon is amorphous carbon (amorphous carbon material) in an sp2 bonding form, carbon, hydrogen, nitrogen, oxygen and the like exist in the resin material, and the nitrogen, the hydrogen, the nitrogen, the oxygen and the like can be remained in a system after treatment, so that the electrical and mechanical properties of the glassy carbon are influenced to a certain extent.

Disclosure of Invention

The invention provides a preparation method of a glassy carbon material, which adopts a single nano diamond material as a precursor to simply, quickly and efficiently prepare the glassy carbon material.

The preparation method of the glassy carbon material provided by the invention is to prepare the glassy carbon material by taking nano diamond as a precursor and sintering the nano diamond in vacuum plasma.

Preferably, the spark plasma sintering is carried out under the vacuum condition, the pressure is controlled to be 30MPa, the temperature is increased to 800 ℃ at the heating rate of 100 ℃/min, and the temperature is kept for 2 min; then the pressure is increased to 50-100MPa, the temperature is increased to 1400 ℃ at the heating rate of 100 ℃/min, and the temperature is kept for 5-10 min.

Preferably, the nano-diamond has a particle size of 5 to 50 nm.

Preferably, the vacuum is less than 10 Pa.

Preferably, the nano-diamond is washed by acid, alkali and deionized water in sequence before plasma sintering, and then is subjected to vacuum drying treatment.

The invention also provides a glassy carbon material prepared by any one of the methods.

Compared with the prior art, the invention has the beneficial effects that:

1. pure inorganic material nano-diamond in an sp3 bonding state is used as a precursor, when a vacuum discharge plasma sintering process is carried out, carbon-carbon bonds of nano-diamond in an sp3 bonding state are converted to sp2 carbon-carbon bonds, the conversion process is carried out layer by layer, the carbon layers are gradually distributed from the outer layer to the nano-diamond core, the converted carbon layers are distributed in an unordered manner, carbon is converted into unordered amorphous carbon from nano-diamond carbon, irregular and unordered graphene strips are generated, and the unordered amorphous carbon can shrink in volume and be extruded into a compact block body due to the fact that the discharge plasma sintering is pressure sintering, and compared with a traditional resin heat treatment process, the preparation process is relatively simple;

2. different pressures within the range of 50-100MPa are applied in the sintering stage, and the dispersed nano-diamond can be converted into a glassy carbon material by keeping the temperature at 1400 ℃ for 5-10 minutes, so that the preparation method is low in cost, pollution-free and simple in process, the conversion rate of sp3 carbon to sp2 carbon can be regulated and controlled by regulating the composition and bonding proportion of graphene strips in the glassy carbon by regulating the sintering temperature and time, the physical and electrical properties of the glassy carbon material can be further regulated and controlled, and the prepared glassy carbon material has the characteristics of high conductivity and high hardness and is suitable for industrial production;

3. the sintered glass carbon material blank shows glass characteristics after being polished by a polishing machine, and can achieve a mirror surface effect after being polished, so that the glass carbon material blank has extremely high smoothness.

Drawings

FIG. 1 is a transmission electron micrograph of a nanodiamond precursor;

FIG. 2 is a transmission electron micrograph of a glassy carbon bulk material;

figure 3 is an external view of a glassy carbon body material.

Detailed Description

The present invention is further described below by way of examples, but the present invention is not limited by these examples. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Example 1

Preparing nano-diamond with the particle size of 5nm by using a detonation method, rinsing and purifying the nano-diamond by using acid, alkali and deionized water to remove surface impurities and functional groups, keeping the temperature of a vacuum oven at 120 ℃ for 24 hours to remove water, placing the dried nano-diamond into a cylindrical graphite mold, and isolating the nano-diamond from the graphite mold through graphite paper with the thickness of 0.01mm so as to prevent the nano-diamond from being adhered to the mold to cause later-stage demolding difficulty; and then placing the graphite mold into a hydraulic press, carrying out cold pressing under the pressure of 10MPa and maintaining the pressure for 5min, then placing the graphite mold into a discharge plasma sintering device, closing a cavity, applying pressure to 30MPa through an upper pressure head and a lower pressure head of the graphite mold, vacuumizing the cavity to be within 10Pa, starting to heat up to 800 ℃ at the heating rate of 100 ℃/min, carrying out heat preservation for 2min, then raising the sintering pressure to 50MPa, heating to 1400 ℃ at the heating rate of 100 ℃/min, carrying out heat preservation for 5min, stopping heating, releasing the pressure after the temperature of a hearth is reduced to the room temperature, taking out the graphite mold, carrying out demolding operation on a tablet press to obtain a glassy carbon blank, and grinding and polishing the glassy carbon blank to obtain the black glassy carbon material with a bright surface, high hardness and high conductivity.

Example 2

Preparing nano-diamond with the particle size of 50nm by using a detonation method, rinsing and purifying the nano-diamond by using acid, alkali and deionized water to remove surface impurities and functional groups, keeping the temperature of a vacuum oven at 120 ℃ for 24 hours to remove water, placing the dried nano-diamond in a graphite mold, isolating the nano-diamond and the graphite mold through graphite paper with the thickness of 0.01mm, and then placing the nano-diamond and the graphite mold on a tablet press under the pressure of 10MPa for prepressing for 5 minutes; and then placing a graphite mold into a cavity of the discharge plasma sintering equipment, applying pressure to 30MPa through an upper pressure head and a lower pressure head of the graphite mold, heating to 800 ℃ at a heating rate of 100 ℃/min after the vacuum degree of the cavity is lower than 10MPa, preserving heat for 2min, then raising the sintering pressure to 50MPa, heating to 1400 ℃ at a heating rate of 100 ℃/min, preserving heat for 5min, stopping heating, releasing pressure after the temperature of a hearth is reduced to room temperature, taking out the graphite mold, demolding to obtain a glassy carbon blank, and grinding and polishing to obtain the glassy carbon material.

Example 3

Preparing nano-diamond with the particle size of 50nm by using a detonation method, rinsing and purifying the nano-diamond by using acid, alkali and deionized water to remove surface impurities and functional groups, keeping the temperature of a vacuum oven at 120 ℃ for 24 hours to remove water, placing the dried nano-diamond in a graphite mold, isolating the nano-diamond and the graphite mold through graphite paper with the thickness of 0.01mm, and then placing the nano-diamond and the graphite mold on a tablet press under the pressure of 10MPa for prepressing for 5 minutes; and then placing a graphite mold into a cavity of the discharge plasma sintering equipment, applying pressure to 30MPa through an upper pressure head and a lower pressure head of the graphite mold, heating to 800 ℃ at a heating rate of 100 ℃/min after the vacuum degree of the cavity is lower than 10MPa, preserving heat for 2min, then raising the pressure to 100MPa, heating to 1400 ℃ at 100 ℃/min, preserving heat for 10min, stopping heating, releasing the pressure after the temperature of a hearth is reduced to room temperature, taking out the graphite mold, demolding to obtain a glassy carbon blank, and grinding and polishing to obtain the glassy carbon material.

Example 4

Preparing nano-diamond with the particle size of 20nm by using a detonation method, rinsing and purifying the nano-diamond by using acid, alkali and deionized water to remove surface impurities and functional groups, keeping the temperature of a vacuum oven at 120 ℃ for 24 hours to remove water, placing the dried nano-diamond in a graphite mold, isolating the nano-diamond and the graphite mold through graphite paper with the thickness of 0.01mm, and then placing the nano-diamond and the graphite mold on a tablet press under the pressure of 10MPa for prepressing for 5 minutes; and then placing a graphite mold into a cavity of the discharge plasma sintering equipment, applying pressure to 30MPa through an upper pressure head and a lower pressure head of the graphite mold, heating to 800 ℃ at a heating rate of 100 ℃/min after the vacuum degree of the cavity is lower than 10MPa, preserving heat for 2min, then raising the pressure to 80MPa, heating to 1400 ℃ at 100 ℃/min, preserving heat for 8min, stopping heating, releasing the pressure after the temperature of a hearth is reduced to room temperature, taking out the graphite mold, demolding to obtain a glassy carbon blank, and grinding and polishing to obtain the glassy carbon material.

Example 5

Preparing nano-diamond with the particle size of 20nm by using a detonation method, rinsing and purifying the nano-diamond by using acid, alkali and deionized water to remove surface impurities and functional groups, keeping the temperature of a vacuum oven at 120 ℃ for 24 hours to remove water, placing the treated nano-diamond in a high-strength graphite mold, isolating nano-diamond powder from the graphite mold through thin graphite paper, and then placing the graphite mold on a hydraulic machine for prepressing for 5 minutes under 10 MPa; then placing a graphite mold into a cavity of the discharge plasma sintering equipment, applying pressure to 30MPa through an upper pressure head and a lower pressure head of the graphite mold, starting a vacuum system, heating to 800 ℃ at a heating rate of 100 ℃/min after the vacuum degree of the cavity is lower than 10MPa, and preserving heat for 2min to discharge residual gas of the nano-diamond; and then increasing the pressure to 70MPa, increasing the temperature to 1400 ℃ at the speed of 100 ℃/min, keeping the temperature for 6min, stopping heating, releasing the pressure after the temperature of the hearth is reduced to room temperature, taking out the graphite mold, demolding to obtain a glassy carbon blank, and grinding, polishing and cutting to obtain a glassy carbon material product in any shape.

Since the glassy carbon materials prepared in examples 1-5 have substantially the same properties, the following description will be made only by taking the glassy carbon material prepared in example 1 as an example.

Fig. 1 is a transmission electron micrograph of a nanodiamond precursor. As can be seen from fig. 1, the nanodiamond precursor mainly exists in the form of nanoparticles, and the existence form of the nanodiamond precursor is obviously changed after the spark plasma sintering treatment.

FIG. 2 is a transmission electron micrograph of a glassy carbon bulk material. As is apparent from fig. 2, the granular nanodiamonds are not present, but instead, amorphous carbon bands exist in a disordered manner, and the existing form of the amorphous carbon bands is not specific and irregular.

Figure 3 is an external view of a glassy carbon body material. As can be seen from FIG. 3, the glassy carbon material prepared by the present application is black, has a bright surface, shows glass characteristics, can achieve a mirror effect after surface polishing, and has extremely high smoothness.

The resistivity of the glassy carbon material prepared in each example was measured with a four-probe, and the room temperature resistivity was 50 to 80 μ Ω · m; the hardness of the glassy carbon material prepared in each example was measured at a load of 5N using a Vickers hardness tester to be 138-250 HV. The difference is mainly determined by the preparation pressure, if the density of the glassy carbon material is higher when the preparation pressure is high, the resistivity is reduced, the hardness index is the same, and the hardness is also increased when the pressure is high.

The above disclosure is only for the specific embodiment of the present invention, but the embodiment of the present invention is not limited thereto, and any variations that can be made by those skilled in the art should fall within the scope of the present invention.