A method for preparing amorphous carbon

Abstract

The application discloses a preparation method of amorphous carbon, which comprises the following steps: uniformly mechanically mixing Ta powder and graphite powder in a planetary ball mill, and then annealing at high temperature to realize the conversion of the graphite into amorphous carbon, and has the advantages of low cost, energy saving and environmental protection.

Description

Technical Field

[0001] This invention relates to a novel method for preparing amorphous carbon based on graphite. Background Technology

[0002] Carbon is one of the most abundant elements in nature, and its atoms have different hybridization modes. The properties of carbon materials change with the hybridization mode of carbon atoms. Based on the material morphology and the degree of order in atomic arrangement, carbon materials can be classified into long-range ordered crystalline carbon and disordered amorphous carbon. Amorphous carbon is a type of carbon composed of sp... 2 Hybridized C atoms and sp 3 Metastable materials composed of hybrid C atoms exhibit a rich variety of microstructures and performance combinations due to the diversity of carbon atom bonding modes and the variability of short-range microstructures. They possess excellent friction-reducing and wear-resistant properties, low dielectric constant, wide bandgap, and good optical transmittance, and are widely used in aerospace, machinery, electronics, and other fields.

[0003] Graphite, also a carbon material, is the most commonly used raw material for preparing amorphous carbon. Currently, the high-temperature, high-pressure method is the most common industrial method for preparing amorphous carbon from graphite. High pressure, as an extreme physical condition, can alter interatomic interactions, regulate bonding patterns, and effectively promote the transformation of carbon atoms in carbon materials from sp to polyatomic. 2 To sp 3 A bonding transformation occurs. This method requires extremely demanding production conditions, utilizing high pressure to synthesize bulk amorphous carbon materials, necessitating large-cavity press technology. The required pressures reach several gigapascals or even higher, and the temperatures reach several thousand degrees Celsius, placing extremely high demands on equipment, resulting in low production efficiency, high preparation costs, and significant difficulty. Furthermore, various deposition techniques have been used to prepare amorphous carbon films, but the deposition process often involves impurities, limiting size due to deposition rate limitations, and generating internal stresses as high as 6-8 GPa during deposition, leading to poor adhesion between the film and the substrate, thus restricting its application areas. Traditional ball milling techniques for preparing amorphous carbon require long-term ball milling in an inert or vacuum atmosphere, resulting in low amorphous carbon conversion rates, and graphite recrystallization, meaning that after ball milling and annealing, a short-range ordered crystal structure emerges. Therefore, developing new methods for preparing amorphous carbon based on graphite is of significant value. Summary of the Invention

[0004] This invention develops a novel method for preparing amorphous carbon. The method utilizes an omnidirectional planetary ball mill to mechanically mix Ta powder and graphite powder uniformly, followed by tableting and then tube sealing annealing, transforming graphite into amorphous carbon under normal pressure.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing amorphous carbon, the method comprising the following steps:

[0007] (1) Mix graphite powder and Ta powder evenly according to a mass ratio of 20-70:1 (preferably 40:1) to obtain the raw material;

[0008] (2) The raw material described in step (1) is placed in a planetary ball mill and milled at a ball-to-material ratio of 60-100:1 (preferably 80:1) for 36-72 hours (preferably at a ball-to-material ratio of 500 rpm and a ball-to-material ratio of 450-550 rpm for 48 hours) to obtain a mixed powder; the ball milling beads used in the ball mill are made of zirconium oxide.

[0009] (3) Annealing treatment: The mixed powder described in step (2) is placed in a quartz tube, the tube is sealed under vacuum (so that the sample is in a sealed quartz tube with near vacuum), and annealed in a muffle furnace at 600-1000℃ for 60-90 min (preferably annealed at 800℃ for 60 min), and cooled at room temperature to obtain the amorphous carbon.

[0010] The ball-to-material ratio refers to the mass ratio of grinding balls to raw materials.

[0011] In an embodiment of the present invention, the mixed powder was compressed into a tablet before being placed into the quartz tube, and then the resulting compressed tablet sample was placed into the quartz tube. The purpose of tablet compression is to shape the sample for subsequent electron microscopy and other detection purposes, and it is not a necessary technical feature of the present invention.

[0012] Furthermore, the graphite powder has a purity of 99.9% and a particle size of 1-10 μm. The Ta powder has a purity of 99.9% and a particle size of 50 nm.

[0013] Preferably, the planetary ball mill is an omnidirectional planetary ball mill, purchased from Changsha Miqi Instrument Equipment Co., Ltd., model number MITR-QMQX-4L. In an embodiment of the present invention, the grinding balls used in the ball mill are made of zirconium oxide. Further, the weight ratio of the 3 / 5 / 8mm grinding balls is 5:3:2.

[0014] The present invention particularly recommends the following method:

[0015] (1) Mix graphite powder and Ta powder evenly at a mass ratio of 40:1 to obtain the raw material;

[0016] (2) The raw material described in step (1) is placed in a planetary ball mill and milled for 48 hours at a ball-to-material ratio of 80:1 and a rotation speed of 500 rpm and a revolution speed of 5 rpm to obtain a mixed powder.

[0017] (3) Annealing treatment: The mixed powder described in step (2) is placed in a quartz tube, the tube is sealed under vacuum (so that the sample is in a sealed quartz tube with near vacuum), annealed in a muffle furnace at 800°C for 60 min, and cooled at room temperature to obtain the amorphous carbon.

[0018] Compared with existing high-temperature and high-pressure processes based on the conversion of graphite into amorphous carbon and existing ball milling technology, the beneficial effects of this invention are: (1) Ta powder and graphite powder are mechanically mixed evenly in an all-round planetary ball mill, and then annealed at high temperature to realize the conversion of graphite into amorphous carbon containing dispersed Ta, which solves the problem of short-range ordered crystal structure after existing ball milling annealing, and has the advantages of low cost, energy saving and environmental protection; (2) This method has low equipment requirements, simple process, high safety, easy operation and can be used for industrial production. Attached Figure Description

[0019] Figure 1 The Raman spectrum of pure graphite powder.

[0020] Figure 2 This is a transmission electron microscope (TEM) image of pure graphite powder.

[0021] Figure 3 Raman spectrum of Example 1 (C:Ta=20:1-36h-800℃ annealing-60min).

[0022] Figure 4 Raman spectrum of Example 2 (C:Ta=20:1-48h-800℃ annealing-60min).

[0023] Figure 5 TEM image of Example 2 (C:Ta=20:1-48h-800℃ annealing-60min).

[0024] Figure 6 Raman spectrum of Example 3 (C:Ta=20:1-72h-800℃ annealing-60min).

[0025] Figure 7 Raman spectrum of Example 4 (C:Ta=40:1-48h-800℃ annealing-60min).

[0026] Figure 8 TEM image of Example 4 (C:Ta=40:1-48h-800℃ annealing-60min).

[0027] Figure 9 EDS-Mapping image of Example 4 (C:Ta=40:1-48h-800℃ annealing-60min).

[0028] Figure 10 Raman spectrum of Example 5 (C:Ta=70:1-48h-800℃ annealing-60min).

[0029] Figure 11 TEM image of Example 5 (C:Ta=70:1-48h-800℃ annealing-60min).

[0030] Figure 12 Raman spectrum of Comparative Example 1 (pure graphite powder - 48h - annealing at 800℃ - 60min). Detailed Implementation

[0031] The present invention will be further described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0032] The tableting conditions in the following examples are: holding pressure at 20 MPa for 2 minutes.

[0033] Example 1

[0034] (1) Graphite powder (prepared by Inner Mongolia Tanghe Technology Co., Ltd., purity 99.9%) and Ta powder (prepared by Shanghai Hanlang New Materials Co., Ltd., purity 99.9%) were weighed at a mass ratio of 20:1 and mixed evenly to obtain the raw materials.

[0035] (2) Place the raw material described in step (1) into a 500ml ball mill jar, add zirconia balls (3 / 5 / 8mm), the total weight of the grinding balls is 500g, and the weight ratio of the 3 / 5 / 8mm grinding balls is 5:3:2, which are 250g, 150g, and 100g respectively. The ball-to-material ratio is 100:1. Seal the ball mill jar with an O-ring, and ball mill for 36 hours in an air atmosphere at a rotation speed of 500rpm and a revolution speed of 5rpm to obtain a mixed powder. The selected grinding ball ratio and ball-to-material weight ratio are to better improve the grinding efficiency of the ball mill.

[0036] (3) Compress the mixed powder described in step (2) into tablets, place the tableted sample into a quartz tube, and seal the tube under vacuum to place the sample in a near-vacuum sealed quartz tube. Place the sealed quartz tube (containing the sample) into a muffle furnace at 800°C, anneal for 60 minutes, remove the sample, and cool it in air to complete the annealing process.

[0037] The composition of the sample after the experiment was observed using laser Raman spectroscopy.

[0038] Figure 1 The Raman spectrum of pure graphite powder mainly shows the distinct 1580 cm⁻¹ of graphite. -1 and 2700cm -1The characteristic peaks correspond to the G peak and the 2D overtone Raman peaks of phonon complete dispersion associated with monolayer or few-layer graphene, respectively.

[0039] Figure 2 The image is a TEM image of pure graphite powder, which mainly shows the crystal plane information of graphite such as (002) and (100).

[0040] Figure 3 The Raman spectrum of Example 1 shows the position at 1140 cm⁻¹. -1 1250cm -1 1350cm -1 1480cm -1 1580cm -1 2700cm -1 2950cm -1 The seven Raman peaks. 1140cm -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1350 cm⁻¹ -1 peak is sp 2 D peak of disordered or defective states related to bonded carbon; 1580 cm⁻¹ -1 peak is sp 2 G peak of bonded carbon; 2700 cm⁻¹ -1 The peak is a frequency-harmonic Raman 2D peak with complete phonon dispersion associated with monolayer or few-layer graphene; 2950 cm⁻¹ -1 The peaks are D+D' peaks related to auxiliary defect expression, typical of the Raman spectrum of amorphous carbon. Compared to intrinsic graphite powder, a peak at 1340 cm⁻¹ appears. -1 The presence of the D peak at this location indicates an increase in defect structures after ball milling. And at 2700cm... -1 The decrease in graphene peak intensity at this location indicates a reduction in the content of single-layer or few-layer graphene after ball milling annealing. Simultaneously, the characteristic graphene peak G shifts to 1588 cm⁻¹. -1 The shift of the G peak to higher wavenumbers also confirms the presence of amorphous carbon in the sample. The addition of Ta powder causes the Ta particles to interact with graphite, disrupting the graphite structure and introducing numerous crystal defects. This leads to an enhancement of the D peak, increased disorder, and the exfoliation and curling of the graphite layers, gradually transforming the layered structure into a long-range disordered structure. These results indicate that after ball milling and annealing with Ta powder, graphite loses its crystalline characteristics and gradually becomes amorphous, forming amorphous carbon.

[0041] Example 2

[0042] (1) Graphite powder (prepared by Inner Mongolia Tanghe Technology Co., Ltd., purity 99.9%) and Ta powder (prepared by Shanghai Hanlang New Materials Co., Ltd., purity 99.9%) were weighed at a mass ratio of 20:1 and mixed evenly to obtain the raw materials.

[0043] (2) Place the raw material described in step (1) into a 500ml ball mill jar, add zirconia balls (3 / 5 / 8mm), the total weight of the ball milling beads is 500g, and the weight ratio of the 3 / 5 / 8mm ball milling beads is 5:3:2, which are 250g, 150g, and 100g respectively. The ball-to-material ratio is 100:1. Seal the ball mill jar with an "O" ring, and ball mill for 48h at a rotation speed of 500rpm and a revolution speed of 5rpm in an air atmosphere to obtain a mixed powder.

[0044] (3) Compress the mixed powder described in step (2) into tablets, place the tableted sample into a quartz tube, and seal the tube under vacuum to place the sample in a near-vacuum sealed quartz tube. Place the sealed quartz tube (containing the sample) into a muffle furnace at 800°C, anneal for 60 minutes, remove the sample, and cool it in air to complete the annealing process.

[0045] The composition of the samples after the experiment was observed using laser Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM).

[0046] Figure 4 The Raman spectrum of Example 2 shows the position at 1140 cm⁻¹. -1 1250cm -1 1350cm -1 1480cm -1 1580cm -1 2700cm -1 2950cm -1 The seven Raman peaks are typical of the Raman spectrum of amorphous carbon. (1140 cm⁻¹) -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1350 cm⁻¹ -1 peak is sp 2 D peak of disordered or defective states related to bonded carbon; 1580 cm⁻¹ -1 peak is sp 2 G peak of bonded carbon; 2700 cm⁻¹ -1 The peak is a frequency-harmonic Raman 2D peak with complete phonon dispersion associated with monolayer or few-layer graphene; 2950 cm⁻¹ -1The peaks are D+D' peaks related to auxiliary defects. With increasing ball milling time, graphite loses its crystalline characteristics and gradually becomes amorphous. The introduction of numerous crystalline defects increases disorder, and the layered structure gradually transforms into a long-range disordered structure. Simultaneously, the characteristic graphite peak G shifts to 1590 cm⁻¹. -1 The shift of the G peak to higher wavenumbers also proves the presence of amorphous carbon in the sample.

[0047] Figure 5 The TEM images for Example 2 show a small number of black nanoparticles on the thin sample area in the low-magnification images. SAED-a mainly shows diffraction rings on the (002), (100), (101), and (110) crystal planes of graphite, as well as diffraction points corresponding to a crystal plane spacing of 0.162 nm, corresponding to the (402) plane of Ta. Compared with intrinsic graphite, the diffraction rings are more diffuse. In the high-magnification images shown in Figures (b) and (c), graphite shows peeling and curling, and the diffraction rings are diffusely distributed. Compared with intrinsic graphite, the lattice fringes of graphite are weakened. The FFT images only show diffraction rings rather than diffraction points, indicating that the ball milling and annealing of Ta powder affects the orderliness of the graphite structure, forming amorphous carbon. This is consistent with the changes in the Raman spectrum.

[0048] Example 3

[0049] (1) Graphite powder (prepared by Inner Mongolia Tanghe Technology Co., Ltd., purity 99.9%) and Ta powder (prepared by Shanghai Hanlang New Materials Co., Ltd., purity 99.9%) were weighed at a mass ratio of 20:1 and mixed evenly to obtain the raw materials.

[0050] (2) Place the raw material described in step (1) into a 500ml ball mill jar, add zirconia balls (3 / 5 / 8mm), the total weight of the ball milling beads is 500g, and the weight ratio of the 3 / 5 / 8mm ball milling beads is 5:3:2, which are 250g, 150g, and 100g respectively. The ball-to-material ratio is 100:1. Seal the ball mill jar with an "O" ring, and ball mill for 72h at a rotation speed of 500rpm and a revolution speed of 5rpm in an air atmosphere to obtain a mixed powder.

[0051] (3) Compress the mixed powder described in step (2) into tablets, place the tableted sample into a quartz tube, and seal the tube under vacuum to place the sample in a near-vacuum sealed quartz tube. Place the sealed quartz tube (containing the sample) into a muffle furnace at 800°C, anneal for 60 minutes, remove the sample, and cool it in air to complete the annealing process.

[0052] The composition of the sample after the experiment was observed using laser Raman spectroscopy.

[0053] Figure 6 The Raman spectrum of Example 3 shows the position at 1140 cm⁻¹. -11250cm -1 1350cm -1 1480cm -1 1580cm -1 2700cm -1 2950cm -1 The seven Raman peaks. 1140cm -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1350 cm⁻¹ -1 peak is sp 2 D peak of disordered or defective states related to bonded carbon; 1580 cm⁻¹ -1 peak is sp 2 G peak of bonded carbon; 2700 cm⁻¹ -1 The peak is a frequency-harmonic Raman 2D peak with complete phonon dispersion associated with monolayer or few-layer graphene; 2950 cm⁻¹ -1 The peaks are D+D' peaks related to auxiliary defect expression. Compared to the Raman spectra of the C:Ta=20:1-36h annealed sample (Example 1) and the C:Ta=20:1-48h annealed sample (Example 2), there is no significant change, which is typical of amorphous carbon Raman spectra. This indicates similar structural characteristics. Meanwhile, the graphite characteristic peak G peak shifts to 1589 cm⁻¹. -1 The shift of the G peak to higher wavenumbers also proves the presence of amorphous carbon in the sample.

[0054] Example 4

[0055] (1) Graphite powder (prepared by Inner Mongolia Tanghe Technology Co., Ltd., purity 99.9%) and Ta powder (prepared by Shanghai Hanlang New Materials Co., Ltd., purity 99.9%) were weighed at a mass ratio of 40:1 and mixed evenly to obtain the raw materials.

[0056] (2) Place the raw material described in step (1) into a 500ml ball mill jar, add zirconia balls (3 / 5 / 8mm), the total weight of the ball milling beads is 500g, and the weight ratio of the 3 / 5 / 8mm ball milling beads is 5:3:2, which are 250g, 150g, and 100g respectively. The ball-to-material ratio is 80:1. Seal the ball mill jar with an "O" ring, and ball mill for 48h at a rotation speed of 500rpm and a revolution speed of 5rpm in an air atmosphere to obtain a mixed powder.

[0057] (3) Compress the mixed powder described in step (2) into tablets, place the tableted sample into a quartz tube, and seal the tube under vacuum to place the sample in a near-vacuum sealed quartz tube. Place the sealed quartz tube (containing the sample) into a muffle furnace at 800°C, anneal for 60 minutes, and then remove the sample to complete the annealing process.

[0058] The composition of the samples after the experiment was observed using laser Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM).

[0059] Figure 7 The Raman spectrum of Example 4 shows the position at 1140 cm⁻¹. -1 1250cm -1 1350cm -1 1480cm -1 1580cm -1 2700cm -1 2950cm -1 The seven Raman peaks. 1140cm -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1350 cm⁻¹ -1 peak is sp 2 D peak of disordered or defective states related to bonded carbon; 1580 cm⁻¹ -1 peak is sp 2 G peak of bonded carbon; 2700 cm⁻¹ -1 The peak is a frequency-harmonic Raman 2D peak with complete phonon dispersion associated with monolayer or few-layer graphene; 2950 cm⁻¹ -1 The peaks are D+D' peaks related to auxiliary defect expression. With increasing carbon-tantalum ratio, the intensity of the D peak in the annealed sample with C:Ta = 40:1 significantly increased compared to that with C:Ta = 20:1-48h (Example 2). The D peak is a sp... 2 The presence of disordered or defective peaks related to bonded carbon indicates an increase in defect concentration in graphite, with the full width at half maximum (FWHM) of the D and G peaks gradually decreasing, while the intensity of the 2D peak in graphene remains essentially unchanged. Simultaneously, the characteristic graphite peak G shifts to 1590 cm⁻¹. -1 The shift of the G peak to higher wavenumbers also proves the presence of amorphous carbon in the sample.

[0060] Figure 8The TEM images for Example 4 show a small number of black nanoparticles on the thin sample area in the low-magnification images. SAED-a mainly shows diffraction rings on the (002), (100), (101), and (110) crystal planes of graphite. Compared with intrinsic graphite, the diffraction rings are more diffuse, and there are also diffraction points corresponding to the interplanar spacing of 0.223 nm, corresponding to the (411) plane of Ta. In the high-magnification images shown in Figures (b) and (d), the graphite is curled into rings, the diffraction rings are diffusely distributed, and the lattice fringes of graphite are weakened. The FFT images only show diffraction rings rather than diffraction points, indicating that the ball milling and annealing of Ta powder affects the orderliness of the graphite structure, forming amorphous carbon. Figure (c) shows a high-magnification image of the black nanoparticles, revealing that they are surrounded by amorphous carbon. The corresponding FT image (FT-c) shows diffraction information for crystal planes with spacings of 0.223 nm and 0.230 nm, corresponding to the (411) and (212) planes of Ta. The angle between the (411) and (212) planes is 84°, consistent with the standard angle between crystal planes. The preceding analysis indicates the presence of well-dispersed Ta particles and amorphous carbon in the sample.

[0061] Figure 9 The EDS-Mapping image for Example 4 shows the distribution of C, O, and Ta elements in the ball-milled sample. The C and Ta elements originate from graphite powder and Ta powder, while the O element comes from oxygen in the air within the ball mill jar and a small amount of oxygen in the quartz tube. The high concentration of Ta in the energy dispersive spectroscopy spectrum confirms that Ta exists not only as nanoparticles but also as dispersed atoms in the ball-milled sample.

[0062] Example 5

[0063] (1) Graphite powder (prepared by Inner Mongolia Tanghe Technology Co., Ltd., purity 99.9%) and Ta powder (prepared by Shanghai Hanlang New Materials Co., Ltd., purity 99.9%) were weighed at a mass ratio of 70:1 and mixed evenly to obtain the raw materials.

[0064] (2) Place the raw material described in step (1) into a 500ml ball mill jar, add zirconia balls (3 / 5 / 8mm), the total weight of the ball milling beads is 500g, and the weight ratio of the 3 / 5 / 8mm ball milling beads is 5:3:2, which are 250g, 150g, and 100g respectively. The ball-to-material ratio is 60:1. Seal the ball mill jar with an "O" ring, and ball mill for 48h at a rotation speed of 500rpm and a revolution speed of 5rpm in an air atmosphere to obtain a mixed powder.

[0065] (3) Compress the mixed powder described in step (2) into tablets, place the tableted sample into a quartz tube, and seal the tube under vacuum to place the sample in a near-vacuum sealed quartz tube. Place the sealed quartz tube (containing the sample) into a muffle furnace at 800°C, anneal for 60 minutes, remove the sample, and cool it in air to complete the annealing process.

[0066] The composition of the samples after the experiment was observed using laser Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM).

[0067] Figure 10 The Raman spectrum of Example 5 shows the position at 1140 cm⁻¹. -1 1250cm -1 1350cm -1 1480cm -1 1580cm -1 2700cm -1 2950cm -1 The seven Raman peaks. 1140cm -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1350 cm⁻¹ -1 peak is sp 2 D peak of disordered or defective states related to bonded carbon; 1580 cm⁻¹ -1 peak is sp 2 G peak of bonded carbon; 2700 cm⁻¹ -1 The peak is a frequency-harmonic Raman 2D peak with complete phonon dispersion associated with monolayer or few-layer graphene; 2950 cm⁻¹ -1 The peak is the D+D' peak related to auxiliary defect expression. The annealed sample with C:Ta = 70:1, compared to C:Ta = 40:1 (Example 4), has... D / I G Lower, while FWHM G Increase, D peak is sp 2 The presence of disordered or defective peaks related to bonded carbon indicates a decrease in defect concentration in graphite, while the 2D peak intensity of graphene remains essentially unchanged. Simultaneously, the characteristic graphite peak G shifts to 1586 cm⁻¹. -1 The shift of the G peak to higher wavenumbers also proves the presence of amorphous carbon in the sample.

[0068] Figure 11The TEM image for Example 5 shows a small number of black particles on the thin sample area, visible at low magnification. SAED-a mainly exhibits diffraction rings of the (002), (100), (101), and (110) crystal planes of graphite, and also diffraction points corresponding to a plane spacing of 0.162 nm, corresponding to the (402) plane of Ta. Figure 11 The high-magnification images shown in (b) and (c) reveal a high degree of graphite curling, with enhanced lattice fringes compared to previous embodiments, resulting in increased diffraction information and reduced amorphous carbon. However, the FFT images only show diffraction rings rather than diffraction points, indicating that the addition of Ta powder and ball milling annealing affects the orderliness of the graphite structure, leading to the formation of amorphous carbon.

[0069] Comparative Example 1

[0070] (1) Graphite powder (prepared by Inner Mongolia Tanghe Technology Co., Ltd., purity 99.9%) was placed in a 500ml ball mill jar, and zirconia balls (3 / 5 / 8mm) were added. The total weight of the ball milling balls was 500g, and the weight ratio of the 3 / 5 / 8mm ball milling balls was 5:3:2, with 250g, 150g, and 100g respectively. The ball-to-powder ratio was 100:1. The ball mill jar was sealed with an O-ring, and the mixture was ball milled for 48 hours in air at a rotation speed of 500rpm and a revolution speed of 5rpm to obtain the mixed powder.

[0071] (2) Compress the mixed powder described in step (1) into tablets, place the tableted sample into a quartz tube, and seal the tube under vacuum to place the sample in a near-vacuum sealed quartz tube. Place the sealed quartz tube (containing the sample) into a muffle furnace at 800°C, anneal for 60 minutes, remove the sample, and cool it in air to complete the annealing process.

[0072] The composition of the sample after the experiment was observed using laser Raman spectroscopy.

[0073] Figure 12 The Raman spectrum for Comparative Example 1 shows the spectrum located at 1140 cm⁻¹. -1 1250cm -1 1350cm -1 1480cm -1 1580cm -1 2700cm -1 2950cm -1 The seven Raman peaks. 1140cm -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1350 cm⁻¹-1 peak is sp 2 D peak of disordered or defective states related to bonded carbon; 1580 cm⁻¹ -1 peak is sp 2 G peak of bonded carbon; 2700 cm⁻¹ -1 The peak is a frequency-harmonic Raman 2D peak with complete phonon dispersion associated with monolayer or few-layer graphene; 2950 cm⁻¹ -1 The peaks are D+D' peaks related to auxiliary defect expression, which are typical Raman spectra of amorphous carbon. Compared with intrinsic graphite powder before ball milling, the Raman spectrum shows a significant change, with a peak appearing at 1140 cm⁻¹. -1 1250cm -1 1340cm -1 1480cm -1 2950cm -1 The four Raman peaks. 1140cm -1 Peak and 1480cm -1 The peak is attributed to the sp of TPA at the grain boundary. 2 CC vibration; 1250cm -1 The peak is caused by the broadened vibrational density of diamond clusters with small grain size or by tetrahedral amorphous carbon; 1340 cm⁻¹ -1 The appearance of peak D at this location indicates that the defect structure increased after ball milling; 2950cm -1 The peak is the D+D' peak related to auxiliary defect expression. Compared with the example, the FWHM in Comparative Example 1 G and FWHM D Slightly lower, sp 2 The increased order and crystallinity of carbon indicate that the addition of Ta powder causes the Ta particles to interact with graphite, disrupting the graphite structure and leading to numerous crystal defects. This results in an enhanced D peak, increased disorder, and the exfoliation and curling of the graphite layers, gradually transforming the layered structure into a long-range disordered structure. These results demonstrate that even without Ta powder, ball milling and annealing of graphite will still result in amorphous carbon formation under mechanical shear forces. However, ball milling with Ta powder makes graphite more prone to amorphization, forming amorphous carbon containing uniformly dispersed Ta.

Claims

1. A method for preparing amorphous carbon, characterized in that... The method includes the following steps: (1) Mix graphite powder and Ta powder evenly at a mass ratio of 20-70:1 to obtain the raw material; (2) The raw material described in step (1) is placed in a planetary ball mill and milled for 36-72 hours at a ball-to-material ratio of 60-100:1 and a rotation speed of 450-550 rpm and a revolution speed of 4-6 rpm to obtain a mixed powder; the ball milling beads used in the ball mill are made of zirconium oxide. (3) Annealing treatment: The mixed powder described in step (2) is placed in a quartz tube, vacuum sealed, annealed in a muffle furnace at 600-1000°C for 60-90 min, and cooled at room temperature to obtain the amorphous carbon.

2. The method for preparing amorphous carbon as described in claim 1, characterized in that: The graphite powder has a particle size of 1-10 μm.

3. The method for preparing amorphous carbon as described in claim 1, characterized in that: The particle size of the Ta powder is 50 nm.

4. The method for preparing amorphous carbon as described in claim 1, characterized in that: In step (1), the mass ratio of graphite powder to Ta powder is 40:

1.

5. The method for preparing amorphous carbon as described in claim 1, characterized in that: The ball-to-material ratio in step (2) is 80:

1.

6. The method for preparing amorphous carbon as described in claim 1, characterized in that: The rotation speed mentioned in step (2) is 500 rpm.

7. The method for preparing amorphous carbon as described in claim 1, characterized in that: The revolution speed mentioned in step (2) is 5 rpm.

8. The method for preparing amorphous carbon as described in claim 1, characterized in that: The ball milling time in step (2) is 48 hours.

9. The method for preparing amorphous carbon as described in claim 1, characterized in that: The annealing temperature in step (3) is 800℃ and the annealing time is 60min.

10. The method for preparing amorphous carbon as described in claim 1, characterized in that... The method is as follows: (1) Mix graphite powder and Ta powder evenly at a mass ratio of 40:1 to obtain raw materials; (2) The raw material described in step (1) is placed in a planetary ball mill and milled for 48 hours at a ball-to-material ratio of 80:1 and a rotation speed of 500 rpm and a revolution speed of 5 rpm to obtain a mixed powder. (3) Annealing treatment: The mixed powder described in step (2) is placed in a quartz tube, vacuum sealed, annealed in a muffle furnace at 800°C for 60 min, and cooled at room temperature to obtain the amorphous carbon.

Images