Powder loaded with nano-diamond on surface as well as preparation method and application of powder

Abstract

The invention provides powder loaded with nano-diamond on the surface as well as a preparation method and application of the powder, belongs to the technical field of powder metallurgy, and aims at solving the technical problem that diamond powder is easy to agglomerate in the preparation process of a nano-diamond composite material. The preparation method of the nano-diamond loaded powder comprises the following steps: (1) plating metallic titanium on the surface of the powder to prepare titanium-plated powder; (2) mixing and ball-milling the nano-diamond, the coating powder and a fluxing agent to obtain mixed powder; and (3) calcining, washing and drying the mixed powder to obtain powder of which the surface is loaded with the nano-diamond. The nano-diamond is loaded on the powder in advance, so that the agglomeration problem of the nano-diamond is effectively solved, and the mechanical property of the composite material is expected to be remarkably improved. In addition, new values can be brought to the fields of national electronic packaging, aerospace and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy, and in particular relates to nano-diamond loaded powder. Background Art

[0002] In fields such as electronic packaging, new energy vehicles, phased array radar, and high-power devices, the demand for thermal management materials is becoming increasingly stringent, with an urgent need for materials featuring high thermal conductivity, low coefficient of expansion, excellent mechanical properties, and good electrical properties. For example, copper, due to its excellent electrical and thermal conductivity, has become a widely used foundational material in the electronics field. However, deficiencies in pure copper, such as hardness, wear resistance, and high-temperature stability, limit its use in high-performance applications. Nanodiamonds not only inherit the inherent properties of diamond, such as high hardness and high thermal conductivity, but also possess unique properties unique to nanomaterials, such as small size effects, large specific surface area effects, and quantum size effects. Since their introduction over 30 years ago, the application of nanodiamonds has continued to expand. Initially, their applications were primarily focused on abrasives and grinding tools, such as polycrystalline materials and polishing agents. With increasing understanding of their properties, nanodiamonds have gradually gained widespread application in a variety of fields, including metal plating, lubricants, magnetic recording systems, and medicine. Loading nanodiamonds onto the surface of copper powder has the potential to combine the advantages of both, resulting in the preparation of composite materials with even higher performance.

[0003] At the same time, in the field of metal engineering, nanodiamond and metal composite coating can increase the service life of parts by 1 to 9 times, reduce the coating thickness by 1 to 2 times, and use standard electroplating equipment, showing its great potential in improving the performance of metal materials. Nanopowders are very prone to agglomeration (soft agglomeration or hard agglomeration) due to their small particle size, large specific surface area, and high surface energy. Traditional dispersion processes are centered around mechanical crushing (stirring, ball milling), ultrasonic cavitation, and chemical modification. The dispersion effect is enhanced through the use of combinations (such as "ultrasound + surfactant" and "ball milling + coupling agent"). However, these processes have disadvantages such as high energy consumption, small batch sizes, and the potential introduction of impurities.

[0004] Furthermore, traditional nanomaterial dispersion processes are not always effective. De-dispersion is prone to occur with prolonged storage of the mixed powder, vibration during transportation, and the effects of powder transfer. Furthermore, during the subsequent metal densification process, diamonds are prone to agglomeration, resulting in insignificant improvements in the composite material's electrical conductivity and mechanical properties. Summary of the Invention

[0005] In view of the technical problem that diamond powder is prone to agglomeration during the preparation of nanodiamond composites, the present invention proposes a powder with nanodiamonds loaded on its surface, its preparation method and application. By adopting the reverse thinking of combining nanodiamond loading, the nanodiamonds are loaded on the powder in advance, which not only effectively solves the agglomeration problem of nanodiamonds, but also is expected to significantly improve the mechanical properties of the composites. In addition, it can also bring new value to the fields of national electronic packaging and aerospace, etc.

[0006] In order to achieve the above object, the technical solution of the present invention is realized as follows:

[0007] A preparation method of a powder with nanodiamonds loaded on its surface, comprising the following steps:

[0008] (1) Coat the surface of the powder with titanium metal to obtain a titanium-coated powder;

[0009] (2) Mix and ball-mill the nanodiamonds, the coated powder and a flux to obtain a mixed powder,

[0010] (3) Calcinate the mixed powder, wash and dry it to obtain a powder with nanodiamonds loaded on its surface.

[0011] The powder is a metal powder or a non-metal powder; the metal powder is Al, Cu, W or Ti; the non-metal powder is Si or C.

[0012] In the step (1), the particle size of the powder is 10 - 500 mesh, and the particle size can be customized according to needs. The microscopic morphology can be spherical, irregular, etc.; the particle size of the nanodiamonds < 200 nm.

[0013] In the step (1), the method of coating the surface of the powder with titanium metal is any one of electroless titanium plating method, physical vapor deposition method or thermal reduction method.

[0014] Preferably, the method of coating the surface of the powder with titanium metal in the step (1) is the thermal reduction method, and the steps are as follows: Add the powder into a titanium source solution for hydrothermal reaction, filter, wash and dry to obtain a powder with titanium oxide loaded on its surface; Set the reducing metal and the powder with the titanium source loaded on its surface in upper and lower layers for thermal reduction treatment, and perform pickling after the reaction ends to obtain a titanium-coated powder.

[0015] The concentration of the titanium source solution is 0.1 - 1.0 mol / L, and the ratio of the metal powder to the titanium source solution is 1:10 - 20 g / mL; the titanium source is any one of titanium tetrachloride, tetrabutyl titanate, titanium oxysulfate, sodium titanate and titanium trichloride.

[0016] The temperature of the hydrothermal reaction is 150 - 200 °C, and the time is 1 - 24 h; the reducing metal is any one of K, Ca, Na, Mg, Al, and Zn; the temperature of the thermal reduction treatment is 200 - 1100 °C, and the time is 0.5 - 6 h.

[0017] In addition, electroless titanium plating, physical vapor deposition, or mechanical alloying are all conventional operations in the art. Taking copper powder as an example, the following examples are provided:

[0018] Electroless titanium plating method: Depositing a titanium layer on the surface of copper powder by a chemical reaction. The steps are as follows: cleaning the copper powder with an organic solvent (such as acetone) to remove surface grease; slightly etching the surface of the copper powder with a dilute acid (such as hydrochloric acid) for activation to enhance the adhesion of the coating; mixing and dissolving a titanium source (such as titanium sulfate, titanium tetrachloride), a reducing agent (sodium hypophosphite, sodium borohydride, etc.), and a complexing agent (sodium citrate, EDTA) to prepare a plating solution; dispersing the pretreated copper powder in the plating solution, heating to 60 - 90 °C, stirring and maintaining the pH value stable (weakly acidic), and the titanium ions are reduced and deposited on the surface of the copper powder under the action of the reducing agent. Filter and wash the copper powder to remove the residual plating solution, and anneal in an inert atmosphere (such as argon) after drying to improve the bonding strength of the coating.

[0019] Physical vapor deposition (PVD) method: Depositing titanium atoms on the surface of copper powder through a physical process (such as evaporation, sputtering). The steps are as follows: cleaning the copper powder to ensure a clean surface; placing the copper powder on a rotating tray or fluidized bed to ensure that the copper powder is fully exposed to the titanium source; evaporation deposition: heating titanium metal to evaporation, and the titanium atoms are deposited on the surface of the copper powder in a vacuum environment or sputtering deposition: bombarding a titanium target with argon ions to cause the titanium atoms to splash and deposit on the surface of the copper powder.

[0020] Salt bath titanium plating method: Immersing the copper powder in a molten salt bath containing titanium halide or other titanium sources, and the titanium atoms diffuse and deposit on the surface of the copper powder at high temperature. It can be selected according to specific requirements and experimental conditions to obtain an ideal titanium plating effect and powder properties.

[0021] Mechanical alloying method: Combining the surfaces of titanium powder and copper powder through high-energy ball milling. The steps are as follows: mixing copper powder and titanium powder in a certain proportion (such as 90% Cu + 10% Ti); ball milling in an inert atmosphere (such as argon) for several hours to dozens of hours; annealing treatment to eliminate stress and enhance the interfacial bonding.

[0022] The mass ratio of the nano-diamond, the coating powder, and the flux is 1:2 - 5:0.05 - 0.15; the flux is sodium chloride or / and potassium chloride; the temperature of the calcination is 200 - 1100 °C, and the time is 1 - 3 h.

[0023] Application of a powder with nano-diamond loaded on the surface in a composite coating.

[0024] Advantages of the present invention:

[0025] (1) The preparation method of the present invention not only has simple steps and convenient operation, but also effectively reduces the poor wettability and unsatisfactory mechanical properties at the interface between copper powder and nanodiamond through a unique titanium oxide plating process. It significantly enhances the interfacial bonding force between copper powder and nanodiamond, and effectively prevents the agglomeration of nanodiamond. In addition, this preparation method has a high yield and low energy consumption, and is suitable for large-scale industrial production.

[0026] (2) The present invention innovatively adopts a reverse thinking method. By performing surface modification on the surface of the metal substrate, a nanoscale diamond particle layer can be effectively coated on the surface of the metal substrate. This unique technical means not only effectively solves the technical problem of the difficult uniform dispersion of nanodiamond particles during application, but also significantly improves the interfacial bonding performance between diamond particles and the metal substrate. Specifically, through surface modification, the surface properties of the metal substrate are optimized, and nanodiamond particles can adhere more firmly to its surface, thus greatly enhancing the bonding strength between the two, effectively overcoming the problem of poor interfacial bonding between diamond and the metal matrix in traditional processes, and providing a more reliable technical guarantee for applications in related fields.

[0027] (3) The ND@Cu powder prepared by the present invention has excellent thermal conductivity, electrical conductivity and mechanical properties, and shows broad application prospects in the fields of electronic packaging, aerospace, automotive manufacturing, etc., and is expected to provide strong technical support for the scientific and technological progress and industrial development in related fields. Description of the drawings

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 It is a schematic structural diagram of the Ti@Cu reaction mold

[0030] Figure 2 It is the SEM image of ND@Cu. Detailed embodiments

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] A method for preparing a powder having a nano-diamond load on its surface comprises the following steps:

[0034] (1) Add 10 g of 200-mesh copper powder to 150 mL of 0.2 mol / L tetrabutyl titanate solution, stir at 50° C. for 3 h, and filter after the reaction, wash with ethanol, dry, and set aside.

[0035] (2) Take 10g each of the aluminum powder and the copper powder containing titanium oxide coating obtained in step (1), as Figure 1 The metal aluminum is placed at the bottom of the graphite calcining boat, with a layer of stainless steel mesh in the middle, and copper powder containing titanium oxide coating is placed on it. Under a fixed flow rate of argon atmosphere, it is kept warm at 800℃ for 5 hours. After cooling, it is taken out, ground, sieved and set aside.

[0036] (3) Add the titanium-plated copper powder obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L, stir evenly, and then let it stand to react until no bubbles are generated to remove a small amount of metallic aluminum that has cooled and solidified on the surface of the copper powder. Finally, wash it with ethanol, dry it, and set it aside.

[0037] (4) Nanodiamonds with a particle size of <100 nm were taken, titanium-coated copper powder and nanodiamonds were mixed in a ratio of 1:2, and then sodium chloride and potassium chloride (mass ratio 1:1) with 10 wt% of the nanodiamonds were added. The mixture was ground into a uniform powder in a corundum mortar. Subsequently, the mixed powder was transferred to an alumina sinter boat and kept at a temperature of 700°C for 2 hours under a fixed flow of argon atmosphere. After cooling, the powder was taken out, washed, dried, ultrasonically treated and dried again to finally obtain copper powder with a uniform surface load of nanodiamonds, as shown in FIG. Figure 2 As shown in (a) and (b), the bright white particles represent nanodiamonds, and the relatively darker particles represent copper powder. The nanodiamonds are relatively evenly loaded on the surface of the copper powder, and there is no agglomeration of nanodiamonds.

[0038] Comparative Example 1

[0039] Mix 10 g of copper powder with a particle size of 200 mesh and nanodiamond with a particle size of <100 nm. Mix the copper powder and nanodiamond in a ratio of 1:2, then add 10 wt% of sodium chloride and potassium chloride (mass ratio 1:1). Place them in a corundum mortar and grind until a uniform powder is obtained. Subsequently, transfer the mixed powder to an alumina boat and keep it at a temperature within 700 °C for 2 hours under a fixed-flow argon atmosphere. After cooling, take out the powder, wash, dry, ultrasonically treat, and dry again to finally obtain the mixed powder. As Figure 2 (c) shows, the nanodiamonds exist in an aggregated form in the grooves of the copper powder particles (indicated by the red arrow), and there is no uniform loading of nanodiamonds on the surface of the copper powder (indicated by the yellow arrow).

[0040] Example 2

[0041] A method for preparing a powder with nanodiamond loading on its surface, comprising the following steps:

[0042] (1) Add 10 g of copper powder with a particle size of 300 mesh to 150 mL of a tetrabutyl titanate solution with a concentration of 0.4 mol / L, stir at 100 °C for 3 h. After the reaction, filter, wash with ethanol, and dry for later use.

[0043] (2) Take 10 g each of metal aluminum powder and the copper powder with a titanium oxide coating obtained in step (1). Place the metal aluminum at the bottom of a graphite boat, add a layer of stainless steel mesh in the middle, and place the copper powder with a titanium oxide coating on top. Keep it at a temperature within 900 °C for 5 h under a fixed-flow argon atmosphere. After cooling, take out, grind, sieve, and reserve for later use.

[0044] (3) Add the titanium-coated copper powder obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L, stir evenly, and let it stand for reaction until no bubbles are generated to remove the small amount of solidified metal aluminum on the surface of the copper powder. Finally, wash with ethanol, dry, and reserve for later use.

[0045] (4) Take nanodiamond with a particle size of <100 nm. Mix the titanium-coated copper powder and nanodiamond in a ratio of 1:3, then add 10 wt% of sodium chloride and potassium chloride (mass ratio 1:1) of the nanodiamond. Place them in a corundum mortar and grind until a uniform powder is obtained. Subsequently, transfer the mixed powder to an alumina boat and keep it at a temperature within 800 °C for 2 hours under a fixed-flow argon atmosphere. After cooling, take out the powder, wash, dry, ultrasonically treat, and dry again to finally obtain copper powder with nanodiamonds uniformly loaded on its surface.

[0046] Example 3

[0047] A method for preparing a powder with nanodiamond loading on its surface, comprising the following steps:

[0048] (1) Add 10 g of 400-mesh copper powder to 150 mL of 0.6 mol / L tetrabutyl titanate solution, stir at 150 °C for 3 h, and filter after the reaction, wash with ethanol, dry, and set aside.

[0049] (2) Take 10 g each of the aluminum metal powder and the copper powder containing titanium oxide coating obtained in step (1), place the aluminum metal at the bottom of a graphite calcining boat, add a layer of stainless steel mesh in the middle, and place the copper powder containing titanium oxide coating on it. In a fixed flow argon atmosphere, keep it in the range of 1000°C for 5 hours. After cooling, take it out, grind it, sieve it, and set it aside.

[0050] (3) Add the titanium-plated copper powder obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L, stir evenly, and then let it stand to react until no bubbles are generated to remove a small amount of metallic aluminum that has cooled and solidified on the surface of the copper powder. Finally, wash it with ethanol, dry it, and set it aside.

[0051] (4) Nanodiamonds with a particle size of <100 nm were taken, titanium-coated copper powder and nanodiamonds were mixed in a ratio of 1:4, and then sodium chloride and potassium chloride (mass ratio 1:1) with 10 wt% of the nanodiamonds were added. The mixture was placed in a corundum mortar and ground into a uniform powder. Subsequently, the mixed powder was transferred to an alumina sinter boat and kept at a temperature range of 900°C for 2 hours under a fixed flow rate of argon atmosphere. After cooling, the powder was taken out, washed, dried, ultrasonically treated and dried again to finally obtain copper powder with a uniform surface load of nanodiamonds.

[0052] Example 4

[0053] A method for preparing a powder having a nano-diamond load on its surface comprises the following steps:

[0054] (1) Add 10 g of 500-mesh copper powder to 150 mL of 0.8 mol / L tetrabutyl titanate solution, stir at 200 °C for 3 h, filter and wash with ethanol after the reaction, dry and set aside.

[0055] (2) Take 10 g each of aluminum metal powder and copper powder containing titanium oxide coating obtained in step (1), place the aluminum metal at the bottom of a graphite calcining boat, add a layer of stainless steel mesh in the middle, and place the copper powder containing titanium oxide coating on it. In a fixed flow argon atmosphere, keep it in the range of 1100°C for 5 hours. After cooling, take it out, grind it, sieve it, and set it aside.

[0056] (3) Add the titanium-plated copper powder obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L, stir evenly, and then let it stand to react until no bubbles are generated to remove a small amount of metallic aluminum that has cooled and solidified on the surface of the copper powder. Finally, wash it with ethanol, dry it, and set it aside.

[0057] (4) Take nanodiamonds with a particle size < 100 nm, mix the copper powder with a titanium-plated layer and the nanodiamonds at a ratio of 1:5, then add sodium chloride and potassium chloride (mass ratio 1:1) which is 10 wt% of the nanodiamonds, place them in a corundum mortar and grind them into a uniform powder. Subsequently, transfer the mixed powder to an alumina boat, keep it warm for 2 hours in an argon atmosphere with a fixed flow rate within the temperature range of 1000 °C. After cooling, take out the powder, wash, dry, perform ultrasonic treatment and dry again, and finally obtain copper powder with nanodiamonds uniformly loaded on its surface.

[0058] Example 5

[0059] A method for preparing a powder with nanodiamonds loaded on its surface, comprising the following steps:

[0060] (1) Add 10 g of copper powder with a particle size of 200 mesh to 150 mL of a tetrabutyl titanate solution with a concentration of 0.2 mol / L, stir at 50 °C for 3 h. After the reaction ends, filter, wash with ethanol, dry, and reserve.

[0061] (2) Take 10 g each of metal magnesium powder and the copper powder with a titanium oxide coating layer obtained in step (1). Place the metal magnesium at the bottom of a graphite boat, add a layer of stainless steel mesh in the middle, and place the copper powder with a titanium oxide coating layer on it. Keep it warm for 5 h within the temperature range of 800 °C in an argon atmosphere with a fixed flow rate. After cooling, take it out, grind, sieve, and reserve.

[0062] (3) Add the copper powder with a titanium-plated layer obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L, stir evenly and let it stand for reaction until no bubbles are generated to remove a small amount of metal magnesium that has cooled and solidified on the surface of the copper powder. Finally, wash with ethanol, dry, and reserve.

[0063] (4) Take nanodiamonds with a particle size < 100 nm, mix the copper powder with a titanium-plated layer and the nanodiamonds at a ratio of 1:2, then add sodium chloride and potassium chloride (mass ratio 1:1) which is 10 wt% of the nanodiamonds, place them in a corundum mortar and grind them into a uniform powder. Subsequently, transfer the mixed powder to an alumina boat, keep it warm for 2 hours in an argon atmosphere with a fixed flow rate within the temperature range of 700 °C. After cooling, take out the powder, wash, dry, perform ultrasonic treatment and dry again, and finally obtain copper powder with nanodiamonds uniformly loaded on its surface.

[0064] Example 6

[0065] A method for preparing a powder with nanodiamonds loaded on its surface, comprising the following steps:

[0066] (1) Add 5 g of silicon powder with a particle size of 10 mesh to 100 mL of a titanium tetrachloride solution with a concentration of 0.1 mol / L, stir at 200 °C for 1 h. After the reaction ends, filter, wash with ethanol, dry, and reserve.

[0067] (2) Take 5 g each of metallic magnesium powder and the silicon powder with a titanium oxide coating obtained in step (1). Place the metallic magnesium at the bottom of a graphite boat, add a layer of stainless steel mesh in the middle, and place the silicon powder with a titanium oxide coating on top. Under an argon atmosphere with a fixed flow rate, keep it at a temperature within 1100 °C for 0.5 h. After cooling, take it out, grind it, sieve it, and set it aside for later use.

[0068] (3) Add the titanium-coated silicon powder obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L. After stirring evenly, let it stand for reaction until no bubbles are generated to remove the small amount of metallic magnesium that has cooled and solidified on the surface of the silicon powder. Finally, wash it with ethanol, dry it, and set it aside for later use.

[0069] (4) Take nanodiamonds with a particle size < 100 nm. Mix the titanium-coated silicon powder and the nanodiamonds at a ratio of 1:5, and then add sodium chloride and potassium chloride (mass ratio 1:1) accounting for 5 wt% of the nanodiamonds. Place them in a corundum mortar and grind them into a uniform powder. Subsequently, transfer the mixed powder to an alumina boat. Under an argon atmosphere with a fixed flow rate, keep it at a temperature within 1100 °C for 1 h. After cooling, take out the powder, wash it, dry it, perform ultrasonic treatment, and then dry it again to finally obtain silicon powder with nanodiamonds uniformly loaded on its surface.

[0070] Example 7

[0071] A method for preparing a powder with nanodiamonds loaded on its surface, comprising the following steps:

[0072] (1) Add 10 g of tungsten powder with a particle size of 100 mesh to 100 mL of a sodium titanate solution with a concentration of 1 mol / L. Stir at 60 °C for 24 h. After the reaction ends, filter it, wash it with ethanol, and dry it for later use.

[0073] (2) Take 10 g each of metallic magnesium powder and the tungsten powder with a titanium oxide coating obtained in step (1). Place the metallic magnesium at the bottom of a graphite boat, add a layer of stainless steel mesh in the middle, and place the tungsten powder with a titanium oxide coating on top. Under an argon atmosphere with a fixed flow rate, keep it at a temperature within 500 °C for 6 h. After cooling, take it out, grind it, sieve it, and set it aside for later use.

[0074] (3) Add the titanium-coated tungsten powder obtained in step (2) to a hydrochloric acid solution with a concentration of 1 mol / L. After stirring evenly, let it stand for reaction until no bubbles are generated to remove the small amount of metallic magnesium that has cooled and solidified on the surface of the tungsten powder. Finally, wash it with ethanol, dry it, and set it aside for later use.

[0075] (4) Take nanodiamond with a particle size < 100 nm, mix the titanium-coated copper powder with the nanodiamond at a ratio of 1:4, then add sodium chloride and potassium chloride (mass ratio 1:1) which is 10 wt% of the nanodiamond, place it in a corundum mortar and grind it into a uniform powder. Subsequently, transfer the mixed powder to an alumina boat, keep it warm for 3 hours in an argon atmosphere with a fixed flow rate within the temperature range of 500 °C. After cooling, take out the powder, and after cleaning, drying, ultrasonic treatment and drying again, finally obtain tungsten powder with nanodiamond uniformly loaded on the surface.

[0076] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a powder with nanodiamond-loaded surface, characterized in that, It includes the following steps: (1) Coating the surface of the powder with titanium metal to obtain titanium-coated powder; (2) Mixing and ball-milling nanodiamond, coated powder and flux to obtain a mixed powder, (3) Calcining the mixed powder, washing and drying to obtain a powder with nanodiamond loaded on the surface.

2. The preparation method of the powder with nano-diamond loaded on the surface according to claim 1, characterized in that, In the step (1), the particle size of the powder is 10 - 500 mesh; the powder is a metal powder or a non-metal powder; the metal powder is aluminum, copper, tungsten or titanium powder; the non-metal powder is silicon or carbon powder.

3. The preparation method of the powder with nanodiamond loaded on the surface according to claim 1, characterized in that, In the step (1), the method for coating the surface of the powder with titanium metal is any one of electroless titanium plating method, physical vapor deposition method, molten salt method or thermal reduction method.

4. The preparation method of the powder with nanodiamond loaded on the surface according to claim 1, characterized in that, In the step (1), the method for coating the surface of the powder with titanium metal is the thermal reduction method, and the steps are: adding the powder into a titanium source solution for hydrothermal reaction, filtering, washing and drying to obtain a powder with titanium oxide loaded on the surface; setting the reducing metal and the powder loaded with the titanium source in upper and lower layers for thermal reduction treatment, and performing pickling after the reaction to obtain titanium-coated powder.

5. The preparation method of the powder with nanodiamond loaded on the surface according to claim 1, characterized in that, The concentration of the titanium source solution is 0.1 - 1.0 mol / L, and the ratio of the metal powder to the titanium source solution is 1:10 - 20 g / mL; the titanium source is any one of titanium tetrachloride, tetrabutyl titanate, titanium oxysulfate, sodium titanate and titanium trichloride.

6. The preparation method of the powder with nanodiamond loaded on the surface according to claim 1, characterized in that, The temperature of the hydrothermal reaction is 50 - 200 °C, and the time is 1 - 24 h; the reducing metal is any one of K, Ca, Na, Mg, Al and Zn; the temperature of the thermal reduction treatment is 200 - 1100 °C, and the time is 0.5 - 6 h.

7. The preparation method of the powder with nano-diamond loaded on the surface according to claim 1, characterized in that, The particle size of the nanodiamond is <200 nm; the mass ratio of the nanodiamond, the coated powder and the flux is 1:2 - 5:0.05 - 0.

15.

8. The preparation method of the powder with nanodiamond loaded on the surface according to claim 1, characterized in that, The flux is sodium chloride or / and potassium chloride; the calcining temperature is 200 - 1100 °C, and the time is 1 - 3 h.

9. A powder with nanodiamond loaded on the surface prepared by the method according to any one of claims 1 - 8.

10. Application of the powder with nanodiamond loaded on the surface according to claim 9 in a composite coating.

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