A hollow cube structure nickel-based graphene oxide composite material, a preparation method thereof and a graphene composite material for laser cladding

Abstract

The present application belongs to the technical field of metal matrix composites, and relates to a hollow cubic structure nickel-based graphene oxide composite material, a preparation method thereof and a graphene composite material for laser cladding. In the hollow cubic structure nickel-based graphene oxide composite material, the hollow cubic structure has 0-2 open faces, and each face is composed of nickel-based Ni / Co-plated graphene oxide nanosheets. The nickel-based Ni / Co-plated graphene oxide nanosheets are formed by nickel nanosheets surface-adsorbed Ni and Co-plated graphene oxide nanosheets; the Ni and Co-plated graphene oxide nanosheets are formed by graphene oxide nanosheets after Co plating, activation and Ni plating. The hollow cubic structure nickel-based graphene oxide composite material is combined with a nickel alloy matrix through ball milling, which improves the dispersibility of the graphene oxide nanosheets, enhances the interface bonding strength of the graphene oxide nanosheets and the matrix, and better utilizes the transverse performance of the graphene oxide nanosheets.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal matrix composites, and relates to a hollow cube structure nickel-based graphene oxide composite material and a preparation method thereof and a graphene composite material for laser cladding. BACKGROUND

[0002] Laser cladding has become one of the most widely used material processing and surface modification technologies in recent decades due to its extremely high power and heat input, extremely fast cooling speed, wide material application range and fewer defects. The cladding layer after laser cladding is uniform in structure, has high bonding strength with the substrate, and can exhibit excellent hardness and wear resistance, so it has a very wide application prospect in the repair and surface protection of engine and turbine blade parts under high temperature and high pressure working conditions. The nickel-based high-temperature alloy applied in laser cladding has very excellent high-temperature resistance, acid and alkali corrosion resistance, friction and wear resistance, etc., and has a similar thermal expansion coefficient with steel, has good wettability with the substrate, and is widely used in chemical industry, steam turbine, ship and nuclear industry fields. On the other hand, in the research of metal matrix composites in recent decades, the uniform dispersion of nanoscale strengthening phases such as graphene, carbon nanotubes and carbon fibers in the matrix is introduced, and the metal matrix composites reinforced by nanocarbon materials with excellent performance are successfully prepared. Among them, the graphene material is a perfect honeycomb lattice formed by single-layer carbon atoms, and has a two-dimensional structure, and the transverse mechanical properties are excellent: the Young's modulus (elastic modulus) is as high as 1100 MPa, and the breaking strength is as high as 130 Mpa.

[0003] But in the laser cladding of nickel-based superalloy, there are few studies on the introduction of nano graphene, because the temperature of the molten pool reaches more than 2000℃ in the process of laser cladding of superalloy. Singh et al. (Singh S K, Neekamal M, Peeters F M. Melting of graphene clusters [J]. Physical Review B, 2013, 87(13): 2095-2100.) simulated and tested the morphology change of graphene at high temperature and found that the nano graphene sheet with complete structure had very good structural stability at high temperature of about 2500K, and judged that the melting point of graphene was about 3000K. If a fiber laser is used as a heat source, the laser energy shows the characteristics of approximate Gaussian distribution, and the energy is concentrated in a circular spot, and the nano graphene sheet will be sent to the center of the spot with the powder, so that the nano graphene sheet structure will be greatly increased. The possibility of being destroyed by the concentrated laser irradiation; if the graphene sheet structure is destroyed, it will lead to the breakage of C-C bond and the presence of a small amount of free C atoms in the molten pool, which will combine with carbon-loving elements to form MC carbide, which will have a certain influence on the mechanical properties of the cladding layer. In view of these characteristics in the process of laser cladding, a protective film can be plated on the surface of graphene to isolate the laser from directly irradiating on the graphene sheet, so as to ensure the structural stability of graphene in the process of cladding. Researchers (Boukhvalov D.W and Katsnelson M.I., Appl. Phys. lett., Vol. 95, No. 2. 2009.) found that transition metal adsorption atoms such as Fe, Ni, Co, especially Co, can significantly reduce the vacancy formation energy of graphene, and can protect graphene from being destroyed.

[0004] The wrinkle structure is the inherent characteristic of graphene sheet, in the graphene nanocomposite, the graphene with wrinkle structure on the surface can establish effective mechanical interlocking effect (Rafiee M A., Rafiee J, Wang Z, et al. Enhanced Mechanical Properties of Nanocomposites at Low Graphene Content [J]. Acs Nano, 2009, 3(12): 3884.). But in the study of graphene / Al composite, researchers found that the formation of carbide at the interface between graphene and Al matrix weakened the mechanical interlocking strengthening effect. Therefore, effectively dispersing graphene in the matrix and avoiding destroying the structural integrity of graphene surface, as well as inhibiting the chemical reaction between graphene and the matrix to generate harmful carbide, is one of the keys to preparing graphene reinforced metal matrix composite materials.

[0005] Meanwhile, studies have shown that the wettability between carbon materials and matrix materials is poor, and it is difficult to effectively form an interface bond. At present, many scholars have carried out chemical modification treatment on liquid dispersion graphene or graphene oxide, etc. to inhibit the aggregation of graphene sheets and improve the wettability between graphene and metal. Some researchers (Tushar Borkar, et al. Excellent strength-ductility combination in nickel-graphite nanoplatelet (GNP / Ni) nanocomposites. Journal of Alloys and Compounds. 2015, 646: 135-144) mixed graphene sheets with Ni powder by ball milling to hinder the aggregation and restacking of graphene sheets. The presence of Ni can improve the wettability between graphene and the matrix phase and improve the bonding force of the matrix interface, which is beneficial to the effective load bearing of graphene and the hindering of dislocation movement, and improves the mechanical properties of the composite material. For example, Zengrong Hu et al. (Zengrong Hu, et al. Laser sintered graphene nickel nanocomposites. Journal of Materials Processing Technology. 2016, 231: 143-150) combined graphene nanosheets containing COOH functional groups with micron-sized nickel powder, and then applied laser sintering. The experimental results show that the graphene is uniformly dispersed in the nickel matrix. However, the above method still cannot guarantee that the transverse performance of the graphene nanosheet is maximally utilized. Studies have shown (Hwang J, Yoon T, Jin S H, et al. Enhanced Mechanical Properties of Graphene / Copper Nanocomposites Using a Molecular-Level Mixing Process [J]. Advanced Materials, 2013, 25 (46): 6724-6729.) that by using a molecular-level mixing method, metal ions such as Ni(NO3)2, Co(NO3)2, Cu(NO3)2, and Cu(C2H3O2)2 are combined with the functional groups on the surface of modified graphene in solution. Then, the oxidation-reduction method is used to uniformly load metal particles on the surface of graphene to form graphene / metal-based composite pre-powder. Then, the composite powder is sintered and densified by SPS (spark plasma sintering) to form a graphene-reinforced metal-based composite material.

[0006] In summary, the current research on graphene reinforced metal matrix composites mainly focuses on the following problems: 1) graphene nanoplatelets (GNPs) will decompose during the process of being combined with the metal matrix, and chemical reactions will occur with the matrix components to generate harmful phases that reduce the performance of the composite; (2) due to the anisotropy of graphene, the transverse performance is not optimally applied; (3) the interfacial bonding strength between GNPs and the matrix is low; (4) GNPs are prone to stacking, agglomeration and poor dispersion. SUMMARY

[0007] The present application aims at the deficiencies in the prior art, and provides a hollow cubic structure nickel-based graphene oxide composite material, a preparation method thereof and a graphene composite material for laser cladding.

[0008] One object of the present application is to provide a hollow cubic structure nickel-based graphene oxide composite material, wherein the hollow cubic structure has 0-2 open faces; and each face of the hollow cubic structure is composed of nickel-based graphene oxide nanoplatelets plated with Ni / Co.

[0009] Preferably, the size of the hollow cubic structure nickel-based graphene oxide composite material is 0.5-50 μm.

[0010] Preferably, the nickel-based graphene oxide nanoplatelets plated with Ni / Co are formed by graphene oxide nanoplatelets adsorbed with plated Ni and Co on the surface of nickel nanoplatelets; and the graphene oxide nanoplatelets plated with Ni and Co are formed by graphene oxide nanoplatelets after being plated with Co, activated and plated with Ni.

[0011] Preferably, the preparation method of the nickel-based graphene oxide nanoplatelets plated with Ni / Co comprises the following steps:

[0012] S1, plating Co: dispersing graphene oxide nanoplatelets in a solvent, then adding a cobalt salt, a sodium salt and polyethylene glycol for reaction, centrifuging, washing and drying to obtain graphene oxide nanoplatelets plated with Co;

[0013] S2, activation: placing the graphene oxide nanoplatelets plated with Co in an acid solution for reaction;

[0014] S3, plating Ni: adding a sodium salt, hydrazine hydrate or hydroxylamine to a nickel salt solution to adjust the pH to be greater than 7, then mixing with the product of step S2 for reaction to obtain graphene oxide nanoplatelets plated with Ni / Co;

[0015] S4, adsorbing the graphene oxide nanoplatelets plated with Ni and Co together with nickel nanoplatelets by electrostatic action to obtain nickel-based graphene oxide nanoplatelets plated with Ni / Co.

[0016] In the preparation method of the graphene oxide nanosheet plated with Ni / Co on the nickel base, the preparation method of the graphene oxide nanosheet is not limited, and the graphene oxide nanosheet can be synthesized by a Hummer molecular level synthesis method, including the following steps: mixing graphite sheets with concentrated sulfuric acid in an ice water bath, then adding potassium permanganate in the ice water bath; then ultrasonically stirring the mixed solution at 20-45℃ for 5-10h; adding water and placing at 80-100℃ for 60-90min; adding 20-50wt% H2O2 and 15-40wt% HCl solution into the above mixed solution respectively, vacuum filtration, and drying the filtration product in a vacuum drying oven for 8-30h to obtain the graphene oxide nanosheet GO nanosheet.

[0017] In step S1, the solvent can be listed as ethylene glycol, acetone, methanol, etc.

[0018] In steps S1 and S3, the sodium salt is preferably one or more of sodium citrate, anhydrous sodium acetate, sodium oxalate, sodium carbonate, and sodium bicarbonate. The sodium salt used in steps S1 and S3 can be the same or different.

[0019] In step S1, the mass ratio of the cobalt salt to the graphene oxide nanosheet is preferably (1-5):1. Preferably, the mass ratio of the cobalt salt, the sodium salt, and the polyethylene glycol is 1:(1-10):(15-30).

[0020] In step S1, the cobalt salt includes but is not limited to one or more of cobalt chloride, cobalt bromide, cobalt sulfate, cobalt nitrate, cobalt formate, cobalt acetate, cobalt citrate, and cobalt tartrate.

[0021] In step S1, the reaction temperature is preferably 120-300℃, and the reaction time is 10-30h. The reaction temperature can be listed as 120, 150, 180, 200, 220, 250, or 300℃, and the reaction time can be listed as 10, 15, 18, 20, 22, 25, or 30h, but is not limited to the listed values, and other values within the range are also applicable.

[0022] In step S1, the drying can be listed as vacuum drying, and the vacuum drying temperature is 60-120℃, and the time is 12-25h.

[0023] In step S2, the acid solution includes but is not limited to one or more of hydrochloric acid solution, sulfuric acid solution, nitric acid solution, and acetic acid solution. The concentration of the acid solution is preferably 0.1-10mol / L.

[0024] In step S2, the reaction is ultrasonic oscillation for 20-100min, followed by standing for 10-30h.

[0025] In step S3, the nickel salt includes, but is not limited to, one or more of nickel sulfate, nickel chloride, and nickel carbonate.

[0026] In step S3, preferably, the molar ratio of the nickel salt, the sodium salt, the hydrazine hydrate or the hydroxylamine is 1:(1-5):(2-8).

[0027] In step S3, preferably, the pH is adjusted to 10-12.

[0028] Preferably, the reaction in step S3 is incubated at 80-150℃ for 1-5h. The reaction temperature can be exemplified as 80, 90, 100, 110, 120, 130, 140, or 150℃, and the incubation time can be exemplified as 1, 2, 3, 4, or 5h, but is not limited to the exemplified values, and other values not exemplified within the value range are also applicable.

[0029] Another object of the present application is to provide a preparation method of a hollow cubic structure nickel-based graphene oxide composite material, comprising the following steps:

[0030] The nickel-based graphene oxide nanosheet plated with Ni / Co is dispersed in an organic solvent, then dropped into an acidified saturated NaCl solution or a saturated KCl solution, after the dropping is completed, vacuum filtration and drying are performed, then heat treatment sintering is performed, the sintered product is soaked in water, then removed, washed, and dried to obtain the hollow cubic structure nickel-based graphene oxide composite material.

[0031] In the above preparation method, the organic solvent can be exemplified as anhydrous ethanol, methanol, acetone, etc.

[0032] In the above preparation method, preferably, the acidified saturated NaCl solution or the saturated KCl solution is adjusted to pH≤5, and the pH is preferably 1-4.

[0033] In the above preparation method, preferably, the dropping time is 1-10min.

[0034] In the above preparation method, preferably, the heat treatment sintering is sintering at 300-600℃ for 15-40h.

[0035] In the above preparation method, preferably, the sintered product is soaked in water for 20h or more, and preferably 20-40h.

[0036] A third object of the present application is to provide a graphene composite material for laser cladding, which is obtained by mixing the above hollow cubic structure nickel-based graphene oxide composite material with nickel alloy particles by ball milling.

[0037] In the graphene composite material for laser cladding, preferably, the particle size of the nickel alloy particles is 50-200 µm,

[0038] Preferably, the nickel alloy can be listed as Ni625, etc.

[0039] In the graphene composite material for laser cladding, preferably, the mass ratio of the hollow cubic structure nickel-based graphene oxide composite material to the nickel alloy particles is 1:(1.5-5).

[0040] In the graphene composite material for laser cladding, preferably, the ball milling comprises: placing the hollow cubic structure nickel-based graphene oxide composite material, nickel alloy particles and grinding balls in a ball mill tank, the ball milling speed is 50-500 rpm, and the ball milling time is 10-15 h.

[0041] The fourth object of the present application is to provide a preparation method of a graphene composite material for laser cladding, comprising the following steps: placing the above-mentioned hollow cubic structure nickel-based graphene oxide composite material and nickel alloy particles in a ball mill tank, and obtaining a graphene composite material for laser cladding after ball milling.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] 1、The present application coats a layer of metal Co on the surface of graphene oxide, and then coats a layer of Ni, which can protect the integrity of the graphene surface, and the outer layer of Ni can form a covalent bond with Co, so that the elastic modulus of the composite material is increased by increasing the bonding type, and Co can significantly reduce the vacancy formation energy, protect the graphene, avoid structural damage, inhibit the chemical reaction at the interface between the graphene and the matrix, avoid the generation of harmful carbides, and completely retain the inherent wrinkle structure of the graphene nanosheet, and can establish effective mechanical engagement with the matrix;

[0044] 2、The hollow cubic structure nickel-based graphene oxide composite material is ball milled to the surface of the nickel alloy particles, which can effectively disperse the graphene in the nickel alloy matrix and avoid damaging the surface structure integrity of the graphene, and the grid structure of the hollow cubic structure nickel-based graphene oxide composite material dispersed on the surface of the nickel alloy powder particles is beneficial to the lateral performance of the graphene in material failure, and plays a secondary strengthening role on the metal matrix composite material;

[0045] 3、The nickel-based graphene oxide composite material with a hollow cubic structure prepared by a special method is combined with a nickel alloy matrix by ball milling, the dispersibility of the graphene oxide nanosheet is improved, the interface bonding strength between the graphene oxide nanosheet and the matrix is enhanced, the transverse performance of the graphene oxide nanosheet is better utilized, and the problem of decomposition of the graphene oxide nanosheet to form a harmful phase in the process of being combined with the metal matrix is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 A reaction schematic diagram for coating Co on the surface of the graphene oxide nanosheet of the present application;

[0047] Figure 2 A reaction schematic diagram for in-situ synthesis of the nickel-based graphene oxide composite material with a hollow cubic structure by using NaCl as a template of the present application;

[0048] Figure 3 A schematic diagram for a ball milling reaction of the nickel-based graphene oxide composite material with a hollow cubic structure and nickel alloy particles;

[0049] Figure 4 An SEM image of the graphene composite material prepared in Example 1 for laser cladding. DETAILED DESCRIPTION

[0050] The technical solutions of the present application are further described and explained below through specific examples and drawings, and it should be understood that the specific examples described herein are only used to help understand the present application and are not used to specifically limit the present application. The drawings used herein are only used to better illustrate the disclosed content of the present application and do not limit the protection scope. If not specifically stated, the raw materials used in the examples of the present application are all commonly used raw materials in the art, and the methods used in the examples are all conventional methods in the art.

[0051] In the following examples and comparative examples, the graphene oxide nanosheet is prepared by the following method:

[0052] Take graphite sheets and 98% concentrated sulfuric acid, and place them in a 1000ml container, mechanically stir them in an ice water bath at 500rpm, and mix them thoroughly; when the temperature is lower than 5℃, slowly add potassium permanganate, and the mass ratio of the concentrated sulfuric acid to the potassium permanganate is 1:3; then the mixed solution is ultrasonically stirred at 40℃ for 8h; 500ml of deionized water is added, and the reaction is carried out at 95℃ for 70min; 40wt% of H2O2 and 15wt% of HCl solution are added to the above mixed solution respectively to remove residual metal ions, vacuum filtration is carried out, and the filtrate is placed in a vacuum drying oven for drying for 18h to obtain the graphene oxide nanosheet.

[0053] Example 1

[0054] The preparation method of the graphene composite material for laser cladding of the embodiment comprises the following steps:

[0055] S1, graphene oxide nanosheets are added into ethylene glycol and ultrasonically oscillated for 1 h, then Co(NO3)2·6H2O, anhydrous sodium acetate and polyethylene glycol are added, the mass ratio of Co(NO3)2·6H2O to graphene oxide nanosheets is 2:1, the mass ratio of Co(NO3)2·6H2O, anhydrous sodium acetate and polyethylene glycol is 1:3:20, and then the mixture is magnetically stirred at 500 rpm for 2 h, and then the mixture is kept at 200°C for 18 h to make Co atoms deposited on the surface of graphene oxide nanosheets; after cooling, the precipitate is collected by a centrifuge, and then washed with deionized water until all ions are removed, and then dried at 90°C under vacuum for 18 hours to obtain Co-plated graphene oxide nanosheets; the reaction schematic diagram of step S1 is shown in Figure 1 ;

[0056] S2, the above Co-plated graphene oxide nanosheets 12 g are mixed with 200 ml of 0.8 mol / L HCl solution (ultrasonically oscillated for 50 min, and left to react for 18 h), so that the Co 3+ attached to the surface of the graphene oxide nanosheets forms active sites, and then washed with deionized water;

[0057] S3, NiCl2 is added to water, the solution is heated to about 100°C, and then ultrasonically oscillated for 50 min until NiCl2 is completely dissolved in water (concentration of 0.2 mol / L), then 0.3 mol / L sodium citrate solution is added to the solution, and ultrasonically oscillated for another 30 min, finally 10 ml of 0.7 mol / L hydrazine hydrate solution (molar ratio of NiCl2, sodium citrate, and hydrazine hydrate is 1:3:4) is added, NaOH is added to adjust the pH to 11, then mixed with the product of step S2, and kept at about 100°C for 2 h until black precipitate Ni / Co-plated graphene oxide nanosheets are produced;

[0058] S4, the Ni / Co-plated graphene oxide nanosheets obtained in step S3 are adsorbed together with nickel nanosheets (mass ratio of 1:2) by electrostatic attraction (the surface of the Ni / Co-plated graphene oxide nanosheets is negatively charged, and will be adsorbed together with the nearby uncharged nickel nanosheets), and finally washed with deionized water and dried to obtain nickel-based Ni / Co-plated graphene oxide nanosheets;

[0059] S5, 10 g of nickel-based Ni / Co plated graphene oxide nanosheet is dispersed in 500 ml of anhydrous ethanol, then ultrasonic oscillation dispersion is performed for 50 min, then an acidified saturated NaCl solution is added dropwise (800 ml of saturated NaCl solution is prepared, heated to 70°C, and concentrated hydrochloric acid is added dropwise to adjust the pH value to 1), the dropwise addition time is controlled for 8 min, after the dropwise addition is completed, vacuum filtration is performed, the filtered product is placed in a vacuum drying box for drying for 6 h, then sintering heat treatment is performed at 450°C for 20 h, finally the sintered product is soaked in deionized water for 24 h, then ultrasonic cleaning is performed, and the Na + and Cl - After drying, a nickel-based graphene oxide composite material with a hollow cube structure with a size of about 1-10 μm is obtained;

[0060] The reaction schematic diagrams of steps S3, S4 and S5 are shown in Figure 2 ;

[0061] S6, the hollow cube structure nickel-based graphene oxide composite material produced in step S5 is mixed with Ni625 metal particles with a particle size of 50-150 μm as a reinforcing phase in a mass ratio of 1:2 by ball milling to obtain a graphene composite material for laser cladding; the ball milling process is as follows: 100 g of hollow cube structure nickel-based graphene oxide composite material and Ni625 mixed powder in each ball milling tank, 60 stainless steel milling balls with a diameter of 10 mm, and a ball milling time of 12 h. The hollow cube structure nickel-based graphene oxide composite material and Ni625 nickel alloy particle ball milling reaction schematic diagram is shown in Figure 3 .

[0062] Figure 4 The SEM diagram of the graphene composite material for laser cladding prepared in Example 1 can be seen from Figure 4 , after the hollow cube structure nickel-based graphene oxide composite material and Ni625 metal particles are mixed by ball milling, the graphene composite material is attached to the surface of the Ni625 metal particles, and the morphology of the Ni625 metal particles is not significantly affected, and the entire graphene composite material for laser cladding is still spherical in morphology.

[0063] Example 2

[0064] The preparation method of the graphene composite material for laser cladding of the present embodiment comprises the following steps:

[0065] S1, graphene oxide nanosheet is added into ethylene glycol and ultrasonically oscillated for 1 h, then Co(NO3)2·6H2O, anhydrous sodium acetate and polyethylene glycol are mixed, the mass ratio of Co(NO3)2·6H2O to graphene oxide nanosheet is 3:1, the mass ratio of Co(NO3)2·6H2O, anhydrous sodium acetate and polyethylene glycol is 1:4:20, and then magnetic stirring is carried out at 400 rpm for 3 h, and then Co atoms are deposited on the surface of graphene oxide nanosheet by keeping at 150℃ for 28 h; after cooling, the precipitate is collected by centrifuge, and washed with deionized water until various ions are removed completely, and then dried at 85℃ under vacuum for 20 hours to obtain Co-plated graphene oxide nanosheet;

[0066] S2, 10 g of the above Co-plated graphene oxide nanosheet is mixed with 150 ml of 1 mol / L HCl solution (ultrasonic oscillation for 30 min, and standing reaction for 28 h) to remove Co 3+ attached to the surface of graphene oxide nanosheet, and then deionized water is used for washing to form active sites;

[0067] S3, NiCl2 is added into water, the solution is heated to about 90℃, and then ultrasonic oscillation is carried out for 60 min until NiCl2 is completely dissolved in water (concentration is 0.3 mol / L), then 0.4 mol / L sodium citrate solution is added into the solution, ultrasonic oscillation is continued for 40 min, finally 10 ml of 0.9 mol / L hydroxylamine solution (molar ratio of NiCl2, sodium citrate and hydroxylamine is 1:2:3) is added, NaOH is added to adjust pH to 10, then the product of step S2 is mixed, and reaction is carried out at about 90℃ for 5 h until black precipitate Ni / Co-plated graphene oxide nanosheet is produced;

[0068] S4, the Ni / Co-plated graphene oxide nanosheet obtained in step S3 is adsorbed together with nickel nanosheet (mass ratio of the two is 1:3) by electrostatic action, and finally deionized water is used for washing and drying to obtain nickel-based Ni / Co-plated graphene oxide nanosheet;

[0069] S5, 10 g of nickel-based Ni / Co-plated graphene oxide nanosheet is dispersed in 500 ml of anhydrous ethanol, and then ultrasonic oscillation is carried out for 50 min, then acidified saturated NaCl solution is added dropwise (800 ml of saturated NaCl solution is prepared, heated to 70℃, and concentrated hydrochloric acid is added dropwise to adjust pH to 1.5), the dropwise adding time is controlled to be 7 min, after the dropwise adding is completed, vacuum filtration is carried out, the filtered product is placed in a vacuum drying oven for drying for 5 h, then sintering is carried out at 400℃ for 28 h, finally the sintered product is soaked in deionized water for 24 h, and then ultrasonic cleaning instrument is used for cleaning, Na + and Cl -After cleaning and drying, the nickel-based graphene oxide composite material with a hollow cubic structure of about 1-10 μm in size can be obtained;

[0070] S6, the hollow cubic structure nickel-based graphene oxide composite material produced in the above step S5 is mixed with Ni625 metal particles with a particle size of 50-150 μm as a reinforcing phase in a mass ratio of 1:3 by ball milling to obtain a graphene composite material for laser cladding; the ball milling process is as follows: 200 g of the hollow cubic structure nickel-based graphene oxide composite material and Ni625 mixed powder in each ball milling tank, 60 stainless steel milling balls with a diameter of 10 mm, and a ball milling time of 10 h.

[0071] Example 3

[0072] The preparation method of the graphene composite material for laser cladding of the present embodiment comprises the following steps:

[0073] S1, graphene oxide nanosheets are added to acetone and ultrasonically oscillated for 1.5 h, then Co(NO3)2·6H2O, anhydrous sodium acetate and polyethylene glycol are added, the mass ratio of Co(NO3)2·6H2O to graphene oxide nanosheets is 4:1, the mass ratio of Co(NO3)2·6H2O, anhydrous sodium acetate and polyethylene glycol is 1:6:25, and then magnetic stirring is carried out at 600 rpm for 4 h, and then the solution is kept at 250℃ for 15 h to allow Co atoms to deposit on the surface of the graphene oxide nanosheets; after cooling, the precipitate is collected by a centrifuge, and then washed with deionized water until all ions are removed, and then dried at 95℃ under vacuum for 16 hours to obtain Co-plated graphene oxide nanosheets;

[0074] S2, 10 g of the above Co-plated graphene oxide nanosheets are mixed with 150 ml of 1.5 mol / L HCl solution (ultrasonic oscillation for 40 min, and standing reaction for 22 h) to remove the Co atoms attached to the surface of the graphene oxide nanosheets and form active sites, and then washed with deionized water; 3+

[0075] S3, NiCl2 is added to water, the solution is heated to about 80℃, and then ultrasonic oscillation is carried out for 70 min until NiCl2 is completely dissolved in water (concentration of 0.5 mol / L), then a 0.5 mol / L sodium citrate solution is added to the solution, ultrasonic oscillation is continued for 40 min, and finally 10 ml of 1.0 mol / L hydrazine hydrate solution (molar ratio of NiCl2, sodium citrate, and hydrazine hydrate is 1:4:7) is added, NaOH is added to adjust the pH to 12, then mixed with the product of step S2, and kept at about 130℃ for 2 h until black precipitate Ni / Co-plated graphene oxide nanosheets are produced;

[0076] ​S4, the Ni and Co plated graphene oxide nanosheet obtained in the step S3 is adsorbed together with the nickel nanosheet (mass ratio 1:3) by electrostatic action, and finally washed with deionized water and dried to obtain a nickel-based Ni / Co plated graphene oxide nanosheet;

[0077] S5, 10g of the nickel-based Ni / Co plated graphene oxide nanosheet is dispersed in 500ml of anhydrous ethanol, then ultrasonic oscillation dispersion is carried out for 50min, then an acidified saturated KCl solution (800ml of saturated KCl solution is prepared, heated to 70℃, and concentrated hydrochloric acid is added dropwise to adjust the pH value to 1.0), the dropwise adding time is controlled for 9min, after the dropwise adding is completed, vacuum filtration is carried out, the filtered product is placed in a vacuum drying box for drying for 7h, then sintering heat treatment is carried out at 500℃ for 22h, finally the sintered product is soaked in deionized water for 24h, then washed by an ultrasonic cleaning instrument, and the Na + and Cl - After washing and drying, a nickel-based graphene oxide composite material with a hollow cube structure with a size of about 1-10um can be obtained;

[0078] S6, the hollow cube structure nickel-based graphene oxide composite material produced in the step S5 is mixed with the Ni625 metal particles with a particle size of 50-150um as a reinforcing phase by ball milling at a mass ratio of 1:3 to obtain a graphene composite material for laser cladding; the ball milling process is as follows: 200g of the hollow cube structure nickel-based graphene oxide composite material and Ni625 mixed powder in each ball milling tank, 60 stainless steel milling balls with a diameter of 10mm, and a ball milling time of 12h.

[0079] Aspects, embodiments, features, and advantages of the present application are to be considered merely illustrative of the principles of the application and are not intended to limit the application to the exact construction and arrangements described. Other embodiments, modifications, and uses will readily occur to those skilled in the art. The application in its broader aspects is therefore not limited to the specific details, representative devices, and illustrative examples shown and described.

[0080] In the preparation method of the present application, the order of each step is not limited to the order listed, and for those skilled in the art, the order of each step can be changed without creative labor, which is within the protection scope of the present application. In addition, two or more steps or actions can be carried out simultaneously.

[0081] It should be noted that the embodiments described herein are merely illustrative of the present application and should not be construed as limiting the scope of the present application. Those skilled in the art can make various modifications or additions to the embodiments described herein or adopt similar ways to replace them without departing from the spirit of the present application. It is not necessary or possible to describe all the embodiments herein. Any obvious changes or variations derived from the spirit of the present application are still within the scope of the present application, and any additional limitations are contrary to the spirit of the present application.

Claims

1. A graphene composite material for laser cladding, characterized by, The graphene composite material for laser cladding is obtained by mixing hollow cubic structure nickel-based graphene oxide composite material and nickel alloy particles through ball milling; the hollow cubic structure has 0-2 open faces; each face of the hollow cubic structure is composed of nickel-based Ni / Co plated graphene oxide nanosheet; The preparation method of the hollow cubic structure nickel-based graphene oxide composite material comprises the following steps: S1, Co plating: dispersing graphene oxide nanosheet in a solvent, then adding cobalt salt, sodium salt and polyethylene glycol for reaction, centrifuging, washing and drying to obtain Co plated graphene oxide nanosheet; S2, activation: placing the Co plated graphene oxide nanosheet in an acid solution for reaction; S3, Ni plating: adding sodium salt, hydrazine hydrate or hydroxylamine to a nickel salt solution, adjusting pH>7, then mixing with the product of step S2 for reaction to obtain Ni / Co plated graphene oxide nanosheet; S4, adsorbing the Ni and Co plated graphene oxide nanosheet and nickel nanosheet together through electrostatic action to obtain nickel-based Ni / Co plated graphene oxide nanosheet; S5, dispersing the nickel-based Ni / Co plated graphene oxide nanosheet in an organic solvent, then dropping into acidified saturated NaCl solution or saturated KCl solution, after dropping is completed, vacuum filtration, drying, then heat treatment sintering, soaking the sintered product in water, then taking out, washing and drying to obtain the hollow cubic structure nickel-based graphene oxide composite material.

2. The graphene composite material for laser cladding according to claim 1, characterized in that, The size of the hollow cubic structure nickel-based graphene oxide composite material is 0.5-50 μm.

3. The graphene composite material for laser cladding according to claim 1, characterized in that, In step S1, the cobalt salt is one or more of cobalt chloride, cobalt bromide, cobalt sulfate, cobalt nitrate, cobalt formate, cobalt acetate, cobalt citrate and cobalt tartrate, and the sodium salt is one or more of sodium citrate, anhydrous sodium acetate, sodium oxalate, sodium carbonate and sodium bicarbonate; And / or, in step S1, the mass ratio of cobalt salt to graphene oxide nanosheet is (1-5):1; And / or, in step S1, the reaction temperature is 120-300 ℃, and the reaction time is 10-30 h.

4. The graphene composite material for laser cladding according to claim 1, characterized in that, In step S2, the reaction is ultrasonic oscillation for 20-100 min, then standing for 10-30 h.

5. The graphene composite material for laser cladding according to claim 1, characterized in that, In step S3, the pH is adjusted to 10-12; And / or, the reaction of step S3 is incubated at 80-150 ℃ for 1-5 h.

6. The graphene composite material for laser cladding according to claim 1, characterized in that, In step S5, the acidified saturated NaCl solution or saturated KCl solution is saturated NaCl solution or saturated KCl solution with pH≤5; And / or, the dropping time is 1-10 min.

7. The graphene composite material for laser cladding according to claim 1, characterized in that, In step S5, the heat treatment sintering is sintering at 300-600 ℃ for 15-40 h; And / or, the sintered product is soaked in water for more than 20 h.

8. The graphene composite material for laser cladding according to claim 1, characterized in that, The particle size of the nickel alloy particles is 50-200 μm. 9.The graphene composite material for laser cladding according to claim 1, characterized in that, The mass ratio of the hollow cubic structure nickel-based graphene oxide composite material to the nickel alloy particles is 1:(1.5-5); And / or, the ball milling comprises: placing the hollow cubic structure nickel-based graphene oxide composite material, nickel alloy particles and grinding balls in a ball mill tank, the ball milling speed is 50-500 rpm, and the ball milling time is 10-15 h.

10. The method of claim 1, wherein the graphene composite material for laser cladding is prepared by the steps of: preparing a graphene solution by dispersing graphene in a solvent; preparing a metal solution by dissolving a metal in a solvent; and mixing the graphene solution and the metal solution. The method comprises the following steps: the hollow cube structure of the nickel-based graphene oxide composite and the nickel alloy particles are placed in a ball mill tank, and the graphene composite material for laser cladding is obtained after ball milling.

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