A diamond particle embedded metal-based diamond coating composite material, a preparation method and application thereof

Abstract

The application discloses a diamond particle inlaid metal base diamond coating composite material and a preparation method and application thereof. Diamond particles are inlaid in a metal base plate to obtain a metal base plate inlaid with diamond particles, heat treatment is carried out, then the heat-treated metal base plate is placed in a nano-diamond seed crystal suspension liquid to implant seed crystals, the metal base plate with implanted seed crystals is obtained, and then the metal base plate is subjected to chemical vapor deposition to grow a diamond film or a doped diamond film, so that the diamond particle inlaid metal base diamond coating composite material is obtained. The diamond particle inlaid metal base diamond coating composite material prepared by the preparation method has the most obvious diamond phase and (111) crystal face preferred growth trend, the diamond film has high bonding strength with the base plate, and has excellent conductivity and catalytic activity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of diamond electrode preparation, and particularly relates to a diamond particle inlaid metal-based diamond coating composite material and a preparation method and application thereof. BACKGROUND

[0002] In the process of chemical vapor deposition of diamond film, due to the large difference in surface energy between diamond and the substrate, and the low adhesion of hydrocarbon groups, the growth of diamond on the heterogeneous substrate usually leads to low nucleation density, long nucleation incubation period and slow deposition rate. Seed implantation of nanodiamond on the substrate helps to improve the nucleation density, reduce the nucleation incubation period, accelerate the nucleation speed, and reduce the voids generated in the nucleation stage, thereby improving the coating quality.

[0003] Nanodiamond particles with a particle size of less than 100 nm, like other nanoparticles, have ultra-high specific surface energy, so the particles often exist in the form of agglomerates, and only physical dispersion methods such as ultrasonic method and ball milling method cannot achieve good dispersion effect, which seriously affects its application in many important fields. SUMMARY

[0004] In view of the deficiencies of the prior art, the first object of the present application is to provide a preparation method of a diamond particle inlaid metal-based diamond coating composite material.

[0005] The second object of the present application is to provide a diamond particle inlaid metal-based diamond coating composite material prepared by the above preparation method.

[0006] The third object of the present application is to provide an application of the diamond particle inlaid metal-based diamond coating composite material.

[0007] In order to achieve the above objects, the present application adopts the following technical solutions:

[0008] The preparation method of the diamond particle inlaid metal-based diamond coating composite material comprises the following steps: embedding diamond particles in a metal substrate to obtain a metal substrate inlaid with diamond particles, heat treating the metal substrate, implanting seeds in the heat-treated metal substrate in a nanodiamond seed suspension to obtain a seed-implanted metal substrate, and then performing chemical vapor deposition on the metal substrate to grow a diamond film or a doped diamond film, thereby obtaining the diamond particle inlaid metal-based diamond coating composite material.

[0009] The preparation method of the present application embeds diamond particles on the flat metal substrate, most of the diamond particles are embedded on the surface of the metal substrate, and a small part of the diamond particles fall off from the surface of the metal substrate and leave pits on the metal substrate. Whether it is a protruding diamond particle or a pit, it can increase the specific surface area of the metal substrate and effectively increase the nucleation site when the subsequent chemical vapor deposition diamond is deposited, which is beneficial to form a dense and uniform diamond film with a large specific surface area, thereby enhancing the comprehensive performance of the diamond electrode. Then, through heat treatment, diffusion reaction occurs between the diamond particles and the metal substrate, forming carbide at the interface to enhance the interface bonding strength, so that the embedded diamond particles are like rivets, greatly enhancing the bonding strength of the subsequent chemical vapor deposition diamond film. Finally, after planting seeds, the diamond film is obtained by chemical vapor deposition. The present application unexpectedly found that the diamond film grown on the metal substrate embedded with diamond particles has the most obvious diamond phase and (111) crystal face preferred growth trend, which further improves the performance of the diamond electrode.

[0010] Preferably, the metal substrate is made of one of the following metals: nickel, niobium, tantalum, copper, titanium, cobalt, tungsten, molybdenum, chromium, iron, or an alloy thereof; or a composite material composed of one or more of the above metals and one or more of the following ceramics: Al2O3, ZrO2, SiC, Si3N4, BN, B4C, AlN, TiB2, TiN, WC, Cr7C3, Ti2GeC, Ti2AlC and Ti2AlN, Ti3SiC2, Ti3GeC2, Ti3AlC2, Ti4AlC3, BaPO3.

[0011] In the present application, the metal substrate includes rod-shaped, tubular, two-dimensional continuous net-shaped structure and two-dimensional closed flat structure.

[0012] Preferably, the metal substrate is first etched by oxalic acid solution, the etching temperature is 50-70℃, the etching time is 1-3h, and the mass fraction of oxalic acid in the oxalic acid solution is 5%-10%.

[0013] Etching the metal substrate by oxalic acid not only removes the oxide film on the surface of the metal substrate, but also etches the metal substrate into a microporous structure to provide more active sites for diamond nucleation. However, the concentration of oxalic acid cannot be too low or too high, and the etching time cannot be too short or too long, otherwise the oxalic acid cannot achieve the purpose of etching the metal substrate or the oxalic acid will excessively etch and damage the stability of the substrate. The temperature cannot be too high, otherwise the oxalic acid will decompose.

[0014] Preferably, the particle size of the diamond particles is 250-500 μm. In the present application, the particle size of the embedded diamond needs to be effectively controlled. If it is not within the scope of the present application, not only the metal substrate cannot be effectively embedded, but also the final composite material will have poor performance.

[0015] Preferably, the diamond particles are pressed into the metal substrate, and the pressing pressure is 10-20 kN.

[0016] The pressing pressure is controlled within the above range, and the final performance is optimal. If the pressure is too small, the diamond particles cannot be embedded in the metal substrate, and if the pressure is too large, the substrate will be broken.

[0017] In actual operation, the diamond particles are mechanically pressed into the etched metal substrate (hereinafter referred to as D-BDD) by a powder tablet press.

[0018] Preferably, the diamond particles are boron-doped diamond particles.

[0019] Preferably, the temperature of the heat treatment is 900-1025℃. After heat treatment, the diamond particles and the metal substrate undergo a diffusion reaction, forming carbides at the interface and enhancing the interfacial bonding strength. If the temperature is too low, carbides cannot be formed, thereby reducing the bonding strength.

[0020] Preferably, in the nanodiamond seed crystal suspension, the mass fraction of nanodiamond particles is 0.01%-0.05%, and the size of nanodiamond particles is 10-100 nm.

[0021] Further preferably, the nanodiamond seed crystal suspension contains a surfactant, and the mass fraction of the surfactant in the nanodiamond seed crystal suspension is 3-5 wt%.

[0022] Still further preferably, the surfactant is selected from at least one of OP-10, polyisobutylene bis-succinimide (T154), sodium hexametaphosphate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, potassium chloride, sodium phosphate, polyethylene glycol, Tween, lysine, glutamic acid, etc. The inventors have found that by appropriately adding a surfactant to the nanodiamond seed crystal suspension, the dispersion stability of nanodiamonds can be improved.

[0023] Preferably, the seed crystal planting method is selected from one of ultrasonic adsorption, electrostatic self-assembly, and electrophoretic deposition, and is preferably electrophoretic deposition. Through the above methods, nanodiamond seed crystals can be planted and adsorbed on the surface of the metal substrate at high density.

[0024] Further preferably, when the seed crystal planting method is ultrasonic adsorption, the seed crystal planting process is as follows: the heat-treated metal substrate is placed in the nanodiamond seed crystal suspension, ultrasonic oscillation treatment is performed for 5-30 min, and then the substrate is rinsed with ultrapure water and dried.

[0025] Further preferably, when the seed crystal planting method is electrophoretic deposition, the seed crystal planting process is as follows: the heat-treated metal substrate and a metal electrode are placed in the nanodiamond seed crystal suspension, a direct current electric field is applied to make the nanodiamond particles electrophoretically deposit on the metal substrate, and then the substrate is rinsed with ultrapure water and dried, wherein the distance between the metal substrate and the metal electrode is 5-15 mm, the voltage of the applied direct current electric field is 15-30 V, and the electrophoretic deposition time is 1-3 min.

[0026] The inventors have found that the electrophoretic technique has the advantages of simple equipment, controllable movement speed, and uniform deposition on a special-shaped surface, and that the use of the electrophoretic technique for nanodiamond seed crystal planting can greatly improve the uniformity of nucleation as the absolute value of the surface potential of the diamond particles in the suspension increases and the nucleation density on the substrate surface increases. Of course, the suspension stability of the nanodiamond particles is the key to the technique in the process of using the electrophoretic technique to operate nanomaterials. Since nanodiamonds are prone to aggregation and stacking, their suspension stability is poor, and nanodiamonds usually need to be surface-modified. In the present application, the addition of a suitable amount of a surfactant to the nanodiamond seed crystal suspension can effectively improve the dispersion stability of the nanodiamonds.

[0027] In a preferred embodiment, the doped diamond film is a boron-doped diamond film.

[0028] In a preferred embodiment, when the chemical vapor deposition is performed, the temperature of the metal substrate is 600-1000°C, and the growth time is 5-10 h, preferably 8-10 h.

[0029] The inventors have also found that a diamond electrode made by embedding diamond particles in a powder mechanical tablet on a metal substrate has the most obvious diamond phase and (111) crystal face preferred growth tendency after 5-10 h of growth, which further improves the performance of the diamond electrode. When no diamond particles are embedded in the metal substrate, the growth direction of the diamond film is not defined.

[0030] In a preferred embodiment, when the chemical vapor deposition is performed to grow a diamond film, the mass flow ratio of the gases introduced is methane:hydrogen = 2-5:90-96; and when the chemical vapor deposition is performed to grow a doped diamond film, the mass flow ratio of the gases introduced is methane:borane:hydrogen = 2-5:2-5:90-96.

[0031] Preferably, the chemical vapor deposition is selected from at least one of hot filament chemical vapor deposition, microwave plasma chemical vapor deposition, direct current plasma chemical vapor deposition, radio frequency plasma chemical vapor deposition, flame combustion chemical vapor deposition, direct current jet plasma chemical vapor deposition, preferably hot filament chemical vapor deposition.

[0032] Further preferably, the temperature of the hot filament is controlled to be 1800-2500 DEG C during the hot filament chemical vapor deposition.

[0033] The application also provides a diamond particle inlaid metal-based diamond coating composite material prepared by the preparation method.

[0034] The application also provides an application of the diamond particle inlaid metal-based diamond coating composite material prepared by the preparation method, and the diamond particle inlaid metal-based diamond coating composite material is applied to one of electrochemical biosensors, electrochemical synthesis and electrochemical detection.

[0035] The application also provides an application of the diamond particle inlaid metal-based diamond coating composite material prepared by the preparation method, and the diamond particle inlaid metal-based diamond coating composite material is applied to degradation of organic wastewater.

[0036] Principle and advantage

[0037] In the preparation method of the application, the diamond particles are pressed and inlaid on the flat metal substrate, most of the diamond particles are inlaid on the surface of the metal substrate, and a small part of the diamond particles falls off from the surface of the metal substrate and leaves pits on the metal substrate. Both the protruding diamond particles and the pits can increase the specific surface area of the metal substrate and effectively increase the nucleation sites of the subsequent chemical vapor deposition diamond, which is beneficial to the formation of a dense and uniform diamond thin film with a large specific surface area, thereby enhancing the comprehensive performance of the diamond electrode. Then, through heat treatment, diffusion reaction occurs between the diamond particles and the metal substrate, carbide is formed at the interface, the interface bonding strength is enhanced, the inlaid diamond particles are like rivets, and the bonding strength of the subsequent chemical vapor deposition diamond film layer is greatly enhanced. Finally, after seed crystal planting, the diamond thin film is obtained through chemical vapor deposition. The inventors have unexpectedly found that the diamond thin film grown on the metal substrate inlaid with diamond particles has the most obvious diamond phase and (111) crystal face preferred growth trend, which further improves the performance of the diamond electrode.

[0038] The diamond particle inlaid metal-based diamond coating composite material prepared by the preparation method of the application has the most obvious diamond phase and (111) crystal face preferred growth trend, the bonding strength between the diamond thin film and the substrate is high, and the diamond thin film has excellent conductivity and catalytic activity. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 XRD patterns of BDD electrodes obtained in the examples, wherein, Figure 1 Ti / D-BDD5 in (a) is the XRD pattern of diamond particle embedded metal based diamond coating composite obtained in Example 1, Ti-BDD5 is the XRD pattern of metal based diamond coating composite obtained in the same way as Ti / D-BDD5, but without embedding diamond particles. Figure 1 Ti / D-BDD 10 is the XRD pattern of diamond particle embedded metal based diamond coating composite obtained in Example 2, Ti / D-BDD 10 is the XRD pattern of metal based diamond coating composite obtained in the same way as Ti / D-BDD5, but without embedding diamond particles. From the XRD patterns, it can be seen that Ti / D-BDD5 (embedded electrode) has obvious trace of Ti-C bond compared with Ti / BDD without embedding, which proves that the embedded diamond particles are well combined with the metal substrate. While Ti / D-BDD 10 compared with Ti / D-BDD5, it can be seen that the substrate surface is basically covered by the oriented (111) growth of diamond film; at the same time, it can be seen that there are still many metal and its compounds on the substrate surface without embedding diamond particles for 10h, which shows that the substrate surface without embedding diamond particles is not completely covered by the diamond film.

[0040] Figure 2 Color removal rate and energy consumption of different BDD electrodes in OG oxidation, from the figure, it can be seen that the degradation effect of Ti / D-BDD 10 is the best. DETAILED DESCRIPTION

[0041] Example 1

[0042] The titanium substrate is etched by oxalic acid solution, the etching temperature is 65℃, the etching time is 1h, the mass fraction of oxalic acid in the oxalic acid solution is 5%, then 400-500μm diamond particles are embedded into the etched metal substrate by powder tablet press machine mechanical embedding method, the embedding pressure is controlled at 15kN, the metal substrate embedded with boron-doped diamond particles is obtained, the metal substrate is controlled at 900℃ for heat treatment, and the heat-treated metal substrate is obtained. 10nm-100nm nanodiamond seeds and OP-10 are added to water to obtain a nanodiamond seed suspension, the mass fraction of nanodiamond particles in the nanodiamond seed suspension is 0.03%, and the mass fraction of surfactant in the nanodiamond seed suspension is 4wt%, then the heat-treated metal substrate is placed in the nanodiamond seed suspension, ultrasonic oscillation treatment is performed for 20min, then ultrapure water is used for rinsing and drying to obtain a seed-implanted metal substrate, the seed-implanted metal substrate is used for hot wire chemical vapor deposition of diamond film, the temperature of the metal substrate during chemical vapor deposition is 1000℃, the temperature of the hot wire is 2100℃, the growth time is 5h, the mass flow ratio of the gas inlet is methane:borane:hydrogen=2:3:95, and the diamond particle embedded metal-based diamond coating composite material (referred to as Ti / D-BDD5) is obtained. The degradation experiment of glucose is carried out, and the experimental results show that the COD degradation rate reaches 90% within 4h, and the corresponding degradation experiment of the electrode sheet without diamond particle embedding (referred to as Ti / -BDD5) shows that the COD removal rate is 79.7%, compared with the BDD electrode without embedding treatment, the performance is improved by 10.3%, and the energy consumption is reduced by 9.6%

[0043] Example 2

[0044] The titanium substrate is etched by oxalic acid solution, the etching temperature is 65℃, the etching time is 1h, the mass fraction of oxalic acid in the oxalic acid solution is 5%, then 250-400μm diamond particles are mechanically embedded into the etched metal substrate by powder tablet press, the embedding pressure is controlled at 10kN, the metal substrate embedded with diamond particles is called D-BDD, the metal substrate is heated at 900℃ to obtain the heat-treated metal substrate. 10nm-100nm nanodiamond seeds and OP-10 are added into water to obtain nanodiamond seed suspension, the mass fraction of nanodiamond particles is 0.05%, the mass fraction of surfactant in the nanodiamond seed suspension is 4wt%, then the heat-treated metal substrate is placed in the nanodiamond seed suspension, ultrasonic treatment is performed for 30min, then the substrate is washed and dried to obtain the seed-implanted metal substrate, the seed-implanted metal substrate is coated with diamond film by hot filament chemical vapor deposition, the temperature of the metal substrate is 1000℃, the temperature of the hot filament is 2100℃, the growth time is 10h, the mass flow ratio of the gas is methane:boron hydride:hydrogen=2:3:95, thus the diamond particle embedded metal-based diamond coating composite material (Ti / D-BDD 10 ) is obtained. The degradation experiment of glucose is performed, the experimental results show that the COD degradation rate is 90% within 4h, the corresponding degradation experiment of the electrode sheet without diamond particle embedding (Ti / BDD 10 ) shows that the COD removal rate is 78%, compared with the BDD electrode without embedding treatment, the performance is improved by 12%, and the energy consumption is reduced by 13.2%.

[0045] Comparative Example 1

[0046] The titanium substrate is etched by oxalic acid solution, the etching temperature is 65℃, the etching time is 1h, the mass fraction of oxalic acid in the oxalic acid solution is 5%, then 4000-500μm pure diamond particles (not BDD) are mechanically embedded into the etched metal substrate by powder tablet press, the embedding pressure is controlled at 10kN, the metal substrate with embedded diamond particles is heated at 900℃ to obtain a heat-treated metal substrate. 10nm-100nm nano-diamond seeds and OP-10 are added into water to obtain a nano-diamond seed suspension, the mass fraction of nano-diamond particles in the suspension is 0.002%, the mass fraction of surfactant in the suspension is 3wt%, then the heat-treated metal substrate is placed in the nano-diamond seed suspension, ultrasonic treatment is performed for 20min, then the substrate is washed and dried to obtain a seed-implanted metal substrate, the seed-implanted metal substrate is coated with diamond film by hot filament chemical vapor deposition, the temperature of the metal substrate is 1000℃, the temperature of the hot filament is 2100℃, the growth time is 5h, the mass flow ratio of the gases is CH4:BH3:H2=2:3:95, thus a boron-doped diamond coating material is obtained. Degradation of glucose experiment is performed, the results show that the COD degradation rate reaches 80% within 4h, the corresponding degradation experiment of the electrode without embedded diamond particles shows that the COD removal rate is 79.7%, compared with the BDD electrode without embedding treatment, the performance is almost the same.

Claims

1. A method of making a diamond particle-inlaid metal-based diamond coating composite material, characterized by: The diamond particles are embedded in the metal substrate to obtain a metal substrate embedded with diamond particles, the metal substrate embedded with diamond particles is subjected to heat treatment, then the heat-treated metal substrate is placed in a nanodiamond seed crystal suspension to implant seed crystals, the metal substrate implanted with seed crystals is obtained, and then the metal substrate is subjected to chemical vapor deposition to grow a diamond film or a doped diamond film, thereby obtaining a diamond particle embedded metal-based diamond coating composite material; The metal substrate is made of titanium; The diamond particles are boron-doped diamond particles.

2. The preparation method of the diamond particle embedded metal-based diamond coating composite material according to claim 1, characterized in that: The metal substrate is subjected to etching treatment with an oxalic acid solution, the etching treatment is performed at a temperature of 50-70°C for 1-3 hours, and the oxalic acid solution contains 5-10% oxalic acid.

3. The method for preparing a diamond particle-embedded metal matrix diamond coating composite material according to claim 1, characterized in that: The particle size of the diamond particles is 250-500 μm. The diamond particles are embedded in the metal substrate by pressing, and the pressure for pressing is 10-20 kN.

4. The method of claim 1, wherein the metal matrix diamond coating composite is a diamond particle embedded metal matrix diamond coating composite. The heat treatment is performed at a temperature of 900-1025°C.

5. The method of claim 1, wherein the metal matrix diamond coating composite is formed by the steps of: The nanodiamond seed crystal suspension contains 0.01-0.05% nanodiamond particles with a size of 10-100 nm. ​ The nanodiamond seed crystal suspension contains a surfactant, and the surfactant accounts for 3-5 wt% in the nanodiamond seed crystal suspension.

6. A method of making a diamond particle embedded metal matrix diamond coating composite according to claim 5, characterised in that: The surfactant is at least one selected from OP-10, polyisobutylene bis-succinimide, sodium hexametaphosphate, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, potassium chloride, sodium phosphate, polyethylene glycol, Tween, lysine, and glutamic acid.

7. A method of making a diamond particle embedded metal matrix diamond coating composite material according to claim 1 or 5, characterized in that: The seed crystal implantation method is selected from ultrasonic adsorption, electrostatic self-assembly, and electrophoretic deposition. When the seed crystal implantation method is ultrasonic adsorption, the process of implanting seed crystals is as follows: the heat-treated metal substrate is placed in the nanodiamond seed crystal suspension, ultrasonic oscillation treatment is performed for 5-30 minutes, and then the metal substrate is washed with ultrapure water and dried. When the seed crystal implantation method is electrophoretic deposition, the process of implanting seed crystals is as follows: the heat-treated metal substrate and a metal electrode are placed in the nanodiamond seed crystal suspension, a direct current electric field is applied to make the nanodiamond particles deposit on the metal substrate by electrophoresis, and then the metal substrate is washed with ultrapure water and dried, the distance between the metal substrate and the metal electrode is 5-15 mm, the voltage of the applied direct current electric field is 15-30 V, and the electrophoretic deposition time is 1-3 minutes.

8. The method of claim 1, wherein the metal matrix diamond coating composite is a diamond particle embedded metal matrix diamond coating composite. The doped diamond film is a boron-doped diamond film. In the chemical vapor deposition, the temperature of the metal substrate is 600-1000°C, and the growth time is 5-10 hours. When the doped diamond film is grown by chemical vapor deposition, the mass flow ratio of the gases is 2-5:2-5:90-96 for methane, borane, and hydrogen, respectively. The chemical vapor deposition is at least one selected from hot-wire chemical vapor deposition, microwave plasma chemical vapor deposition, direct current plasma chemical vapor deposition, radio frequency plasma chemical vapor deposition, flame combustion chemical vapor deposition, and direct current jet plasma chemical vapor deposition.

9. A diamond particle embedded metal-based diamond coating composite material prepared by the method of any one of claims 1-8.

10. Use of a diamond particle embedded metal-based diamond coating composite material produced by the production method according to any one of claims 1 to 8, characterized in that: The diamond particle embedded metal-based diamond coating composite material is applied to one of electrochemical biosensors, electrochemical synthesis, and electrochemical detection.

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