A corrosion-resistant composite metal material for construction and its preparation method

Abstract

The present invention discloses a corrosion-resistant composite metal material for construction and its preparation method. First, a transition layer is formed on the surface of a steel bar by plasma spraying to obtain a pre-coated steel bar. The pre-coated steel bar is then subjected to an alternating magnetic field treatment and cold sprayed with a premix to form a surface coating, thereby obtaining the corrosion-resistant composite metal material. The transition layer is made from a mixture of silicon powder, zirconium diboride powder, and magnetic boron nitride. The premix is prepared from titanium powder, silicon carbide, zirconium carbide, polyvinyl alcohol, polyethylene glycol 400, and other raw materials. The composite metal material prepared by the present invention has excellent corrosion resistance.

Description

Technical Field

[0001] The present invention relates to a corrosion-resistant composite metal material for construction and a preparation method thereof, belonging to the technical field of construction materials. Background Art

[0002] With the rapid development of the national economy, the demand for steel bars for construction is increasing, and the quality requirements for steel bars are getting higher and higher.

[0003] For steel bars used in construction, corrosion resistance is very important. It is directly related to the service life of the steel bars and is closely related to building safety.

[0004] In recent years, coated rebar has been used in the construction industry. Compared to ordinary rebar, coated rebar generally offers better corrosion resistance. However, some elements (such as Mn, Si, Ti, Nb, and Al) tend to accumulate on the surface during the cold rolling and recrystallization annealing process before hot-dip galvanizing, forming a thin oxide film. This reduces the adhesion of the galvanized layer and leads to a decrease in corrosion resistance.

[0005] Patent application CN102765895A discloses a ceramic-coated rebar. The coating comprises ordinary rebar and a ceramic coating covering the outer surface of the ordinary rebar. The coating, with a thickness ranging from 4 to 6 μm, is formed by applying the ceramic coating to the ordinary rebar and then curing it. The ceramic coating is a water-based inorganic coating with good heat and wear resistance. However, this patented technology suffers from limited coating adhesion, and the coating's lifespan cannot be guaranteed in harsh environments, negating any inherent advantages.

[0006] Patent application CN102943547A discloses a double-layer epoxy resin-coated rebar, with a corrosion-resistant layer and a wear-resistant layer sprayed sequentially around the outer periphery of the rebar. The corrosion-resistant layer utilizes a seawater-resistant, melt-bonded epoxy-modified powder coating, while the wear-resistant layer utilizes a wear-resistant, melt-bonded epoxy-modified powder coating. This patent application also suffers from poor coating adhesion, and long-term corrosion resistance cannot be guaranteed. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a corrosion-resistant composite metal material for construction and a preparation method thereof, which has good corrosion resistance.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0010] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0011] (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0012] The transition layer is made of silicon powder, zirconium diboride powder and magnetic boron nitride material in a mass ratio of 10:3-4:0.1-0.2;

[0013] The premix is prepared by the following method, in parts by weight: 30 to 40 parts of titanium powder, 20 to 30 parts of silicon carbide, 20 to 30 parts of zirconium carbide, 1 to 1.5 parts of polyvinyl alcohol, and 1 to 1.5 parts of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, spray-dried to obtain mixed particles, and degreased and reduced under a hydrogen atmosphere to obtain the premix.

[0014] Preferably, the magnetic boron nitride material is prepared by the following method:

[0015] (A) adding hexagonal boron nitride to an acid solution 60 to 70 times its weight, stirring at 50 to 60°C and 1000 to 2000 r / min for 25 to 35 hours, naturally cooling to room temperature (25°C), filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid;

[0016] (B) dispersing the intercalated boron nitride in an equal amount of isopropanol, ultrasonically oscillating the mixture at 60-80 kHz and 300-500 W for 15-20 hours, centrifuging the mixture at 5000-6000 rpm for 30-40 minutes, collecting the supernatant, washing the mixture with water until neutral, and drying the mixture at 90-100° C. for 30-40 hours to obtain boron nitride nanosheets;

[0017] (C) Adding boron nitride nanosheets and ferrous chloride tetrahydrate to deionized water, ultrasonically treating them at 60-80kHz and 180W-200W for 3-5 hours to obtain a boron nitride nanosheet dispersion, slowly adding a 5 mg / mL sodium hydroxide solution to the boron nitride nanosheet dispersion while stirring, and completing the addition over 30 minutes, then adding a 5 mg / mL hydrogen peroxide solution dropwise. When the solution changes from gray-blue to black, the addition is stopped, and the solution is ultrasonically treated for another 20-30 minutes, magnetically separated, and washed alternately with deionized water and anhydrous ethanol for 3-4 times, and vacuum dried at 90-100°C for 8-10 hours to obtain the magnetic boron nitride material; wherein the mass ratio of boron nitride nanosheets, ferrous chloride tetrahydrate, deionized water, and sodium hydroxide solution is 1:2-3:20-30:10-12.

[0018] Preferably, when preparing the premix, the ball milling process conditions are: 300-400 r / min ball milling for 18-20 hours; the inlet temperature and outlet temperature of the spray drying are 180-200°C and 150-160°C respectively; the degreasing and reduction process conditions are: 450-550°C treatment for 3-4 hours.

[0019] Preferably, in step (1), the steel bar is pretreated, specifically by mechanically grinding the steel bar surface to expose a bright fresh metal surface, then degreasing the steel bar with a degreasing liquid, and then shot blasting the steel bar.

[0020] Further preferably, the degreasing liquid is obtained by uniformly mixing a degreasing agent and water in a mass ratio of 1:15 to 20.

[0021] More preferably, the specific method of degreasing treatment is: completely immerse the steel bar in a degreasing solution at 70-80°C, keep warm for 15-20 minutes, take it out and dry it at 100-110°C for 8-10 minutes.

[0022] More preferably, the specific method of shot blasting is: using a 20-30kW shot blasting machine to load steel shots with a diameter of 0.6-0.8 mm to shot blast the surface of the steel bar for 10-20 minutes.

[0023] Preferably, in step (1), the process conditions of plasma spraying are: spraying distance 80-100 mm, powder feeding rate 60-65 g / min, argon flow rate 30-40 L / min, hydrogen flow rate 8-9 L / min, current 50-60 A, and voltage 60-65 V.

[0024] Preferably, in step (1), the thickness of the transition layer is 0.2 to 0.3 mm.

[0025] Preferably, in step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 20 to 30 MHz, the magnetic field is 30 to 40 Gs, and the treatment time is 30 to 40 minutes.

[0026] Preferably, in step (2), the process conditions of cold spraying are: nitrogen is used as the powder feeding gas, the powder feeding rate is 30-40 g / min, the powder feeding gas preheating temperature is 350°C-400°C, the powder feeding rate is 20-30 g / min, the spraying distance is 20-30 mm, and the cooling rate is 40-50°C / s.

[0027] Preferably, in step (2), the thickness of the surface coating is 0.5 to 0.7 mm.

[0028] A corrosion-resistant composite metal material for construction is obtained by the above-mentioned preparation method.

[0029] Beneficial effects of the present invention:

[0030] The present invention first plasma sprays the surface of steel bars to form a transition layer, resulting in pre-coated steel bars. The pre-coated steel bars are then subjected to an alternating magnetic field treatment and cold sprayed with a premix to form a surface coating, resulting in a corrosion-resistant composite metal material. The transition layer is made from a mixture of silicon powder, zirconium diboride powder, and magnetic boron nitride; the premix is prepared from titanium powder, silicon carbide, zirconium carbide, polyvinyl alcohol, polyethylene glycol 400, and other raw materials. The composite metal material produced by the present invention has excellent corrosion resistance.

[0031] The present invention sequentially applies plasma spraying and cold spraying to the steel bar surface, with an alternating magnetic field treatment added between the two spraying processes. The transition layer contains a magnetic boron nitride material. Under the influence of the alternating magnetic field, the magnetic boron nitride material improves the transition layer's microstructure, strengthening the bond between the steel bar, the transition layer, and the subsequent surface coating, ensuring the product's long-term corrosion resistance.

[0032] The premix is prepared using titanium powder, silicon carbide, zirconium carbide, polyvinyl alcohol, polyethylene glycol 400, and the like as raw materials. On the one hand, the corrosion resistance of the product is improved through the synergistic effect of titanium powder, silicon carbide, and zirconium carbide. On the other hand, the premix prepared by the present invention has a spherical structure, good fluidity, and good cold spraying effect, further improving the corrosion resistance of the product. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the embodiments. It should be noted that the following description is only for explaining the present invention and does not limit the content thereof.

[0034] The steel bars in the examples and comparative examples were HPB300 with a diameter of 10 mm.

[0035] Example 1:

[0036] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0037] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0038] (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0039] The transition layer is made of a mixture of 10 kg silicon powder (325 mesh, Chengdu Keliang Building Materials Co., Ltd.), 3 kg zirconium diboride powder (1 μm, Nangong Kejin Welding Materials Co., Ltd.), and 0.1 kg magnetic boron nitride material.

[0040] The premix is prepared by the following method: 30 kg of titanium powder (200 mesh, Hebei Ruihuang Metal Materials Co., Ltd.), 20 kg of silicon carbide (200 mesh, Henan Hengxing Metallurgical Materials Co., Ltd.), 20 kg of zirconium carbide (200 mesh, Hubei Xingdongcheng Chemical Co., Ltd.), 1 kg of polyvinyl alcohol (Jinan Jinniu Chemical Co., Ltd.), and 1 kg of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, which is spray-dried to obtain mixed particles, and then degreased and reduced under a hydrogen atmosphere to obtain the obtained product.

[0041] The magnetic boron nitride material is prepared by the following method:

[0042] (A) adding hexagonal boron nitride to an acid solution 60 times its weight, stirring at 50°C and 1000 rpm for 25 hours, naturally cooling to room temperature (25°C), filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid;

[0043] (B) The intercalated boron nitride was dispersed in an equal amount of isopropanol, ultrasonically treated at 60 kHz and 300 W for 15 hours, centrifuged at 5000 rpm for 30 minutes, and the supernatant was collected, washed with water until neutral, and dried at 90°C for 30 hours to obtain boron nitride nanosheets.

[0044] (C) 0.1 kg of boron nitride nanosheets and 0.2 kg of ferrous chloride tetrahydrate were added to 2 kg of deionized water and ultrasonically treated at 60 kHz and 180 Hz for 3 hours to obtain a boron nitride nanosheet dispersion. 1 kg of a 5 mg / mL sodium hydroxide solution was slowly added dropwise to the boron nitride nanosheet dispersion while stirring. The addition was completed over 30 minutes. Then, a 5 mg / mL hydrogen peroxide solution was added dropwise. When the solution turned from gray-blue to black, the addition was stopped. The solution was ultrasonically treated for another 20 minutes, magnetically separated, and washed alternately with deionized water and anhydrous ethanol three times. The solution was vacuum-dried at 90°C for 8 hours to obtain the magnetic boron nitride material.

[0045] When preparing the premix, the ball milling process conditions are: 300r / min ball milling for 18 hours; the inlet temperature and outlet temperature of the spray drying are 180°C and 150°C respectively; the degreasing and reduction process conditions are: 450°C treatment for 3 hours.

[0046] In step (1), the steel bars are pretreated by mechanically grinding the steel bar surface to expose a bright, fresh metal surface, then degreasing the steel bar using a degreasing solution and then shot blasting the steel bar. The degreasing solution is obtained by mixing a degreasing agent (KX-818, Dongguan Kexin Chemical Co., Ltd.) and water in a mass ratio of 1:15.

[0047] The specific method of degreasing treatment is: immerse the steel bars completely in 70℃ degreasing liquid, keep warm for 15 minutes, take them out and dry them at 100℃ for 8 minutes.

[0048] The specific method of shot blasting is: use a 20kW shot blasting machine to load steel shots with a diameter of 0.6mm to shot blast the steel bar surface for 10 minutes.

[0049] In step (1), the process conditions of plasma spraying are: spraying distance 80 mm, powder feeding rate 60 g / min, argon flow rate 30 L / min, hydrogen flow rate 8 L / min, current 50 A, and voltage 60 V.

[0050] In step (1), the thickness of the transition layer is 0.2 mm.

[0051] In step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 20 MHz, the magnetic field is 30 Gs, and the treatment time is 30 minutes.

[0052] In step (2), the process conditions of cold spraying are: nitrogen as powder feeding gas, powder feeding rate of 30 g / min, powder feeding gas preheating temperature of 350°C, powder feeding rate of 20 g / min, spraying distance of 20 mm, and cooling rate of 40°C / s.

[0053] In step (2), the thickness of the surface coating is 0.5 mm.

[0054] Example 2:

[0055] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0056] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0057] (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0058] The transition layer is made of a mixture of 10 kg silicon powder (325 mesh, Chengdu Keliang Building Materials Co., Ltd.), 4 kg zirconium diboride powder (1 μm, Nangong Kejin Welding Materials Co., Ltd.), and 0.2 kg magnetic boron nitride material.

[0059] The premix is prepared by the following method: 40 kg of titanium powder (200 mesh, Hebei Ruihuang Metal Materials Co., Ltd.), 30 kg of silicon carbide (200 mesh, Henan Hengxing Metallurgical Materials Co., Ltd.), 30 kg of zirconium carbide (200 mesh, Hubei Xingdongcheng Chemical Co., Ltd.), 1.5 kg of polyvinyl alcohol (Jinan Jinniu Chemical Co., Ltd.), and 1.5 kg of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, which is spray-dried to obtain mixed particles, and then degreased and reduced under a hydrogen atmosphere to obtain the obtained product.

[0060] The magnetic boron nitride material is prepared by the following method:

[0061] (A) adding hexagonal boron nitride to an acid solution 70 times its weight, stirring at 60°C and 2000 rpm for 35 hours, naturally cooling to room temperature (25°C), filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid;

[0062] (B) The intercalated boron nitride was dispersed in an equal amount of isopropanol, ultrasonically treated at 80 kHz and 500 W for 20 hours, centrifuged at 6000 rpm for 40 minutes, and the supernatant was collected, washed with water until neutral, and dried at 100°C for 40 hours to obtain boron nitride nanosheets.

[0063] (C) 0.1 kg of boron nitride nanosheets and 0.3 kg of ferrous chloride tetrahydrate were added to 3 kg of deionized water and ultrasonically treated at 80 kHz and 200 W for 5 hours to obtain a boron nitride nanosheet dispersion. 1.2 kg of a 5 mg / mL sodium hydroxide solution was slowly added dropwise to the boron nitride nanosheet dispersion while stirring. The addition was completed over 30 minutes. Then, a 5 mg / mL hydrogen peroxide solution was added dropwise. When the solution turned from gray-blue to black, the addition was stopped. The solution was ultrasonically treated for another 30 minutes, magnetically separated, and washed alternately with deionized water and anhydrous ethanol four times. The solution was vacuum-dried at 100°C for 10 hours to obtain the magnetic boron nitride material.

[0064] When preparing the premix, the ball milling process conditions are: 400r / min ball milling for 20 hours; the inlet temperature and outlet temperature of the spray drying are 200℃ and 160℃ respectively; the degreasing and reduction process conditions are: 550℃ treatment for 4 hours.

[0065] In step (1), the steel bars are pretreated by mechanically grinding the steel bar surface to expose a bright, fresh metal surface, then degreasing the steel bar using a degreasing solution and then shot blasting the steel bar. The degreasing solution is obtained by mixing a degreasing agent (KX-818, Dongguan Kexin Chemical Co., Ltd.) and water in a mass ratio of 1:20.

[0066] The specific method of degreasing treatment is: immerse the steel bars completely in 80℃ degreasing liquid, keep warm for 20 minutes, take them out and dry them at 110℃ for 10 minutes.

[0067] The specific method of shot blasting is: use a 30kW shot blasting machine to load steel shots with a diameter of 0.8mm to shot blast the steel bar surface for 20 minutes.

[0068] In step (1), the process conditions of plasma spraying are: spraying distance 100 mm, powder feeding rate 65 g / min, argon flow rate 40 L / min, hydrogen flow rate 9 L / min, current 60 A, and voltage 65 V.

[0069] In step (1), the thickness of the transition layer is 0.3 mm.

[0070] In step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 30 MHz, the magnetic field is 40 Gs, and the treatment time is 40 minutes.

[0071] In step (2), the process conditions of cold spraying are: nitrogen as powder feeding gas, powder feeding rate of 40 g / min, powder feeding gas preheating temperature of 400 °C, powder feeding rate of 30 g / min, spraying distance of 30 mm, and cooling rate of 50 °C / s.

[0072] In step (2), the thickness of the surface coating is 0.7 mm.

[0073] Example 3:

[0074] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0075] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0076] (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0077] The transition layer is made of a mixture of 10 kg silicon powder (325 mesh, Chengdu Keliang Building Materials Co., Ltd.), 3.5 kg zirconium diboride powder (1 μm, Nangong Kejin Welding Materials Co., Ltd.), and 0.15 kg magnetic boron nitride material.

[0078] The premix is prepared by the following method: 35 kg of titanium powder (200 mesh, Hebei Ruihuang Metal Materials Co., Ltd.), 25 kg of silicon carbide (200 mesh, Henan Hengxing Metallurgical Materials Co., Ltd.), 25 kg of zirconium carbide (200 mesh, Hubei Xingdongcheng Chemical Co., Ltd.), 1.2 kg of polyvinyl alcohol (Jinan Jinniu Chemical Co., Ltd.), and 1.2 kg of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, which is spray-dried to obtain mixed particles, and then degreased and reduced under a hydrogen atmosphere to obtain the obtained product.

[0079] The magnetic boron nitride material is prepared by the following method:

[0080] (A) adding hexagonal boron nitride to an acid solution 65 times its weight, stirring at 55°C and 2000 rpm for 30 hours, naturally cooling to room temperature (25°C), filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid;

[0081] (B) The intercalated boron nitride was dispersed in an equal amount of isopropanol, ultrasonically treated at 70 kHz and 400 W for 18 hours, centrifuged at 6000 rpm for 35 minutes, and the supernatant was collected, washed with water until neutral, and dried at 95°C for 35 hours to obtain boron nitride nanosheets.

[0082] (C) 0.1 kg of boron nitride nanosheets and 0.25 kg of ferrous chloride tetrahydrate were added to 2.5 kg of deionized water and sonicated at 70 kHz and 200 W for 4 hours to obtain a boron nitride nanosheet dispersion. 1.1 kg of a 5 mg / mL sodium hydroxide solution was slowly added dropwise to the boron nitride nanosheet dispersion while stirring. The addition was completed over 30 minutes. Then, a 5 mg / mL hydrogen peroxide solution was added dropwise. When the solution turned from gray-blue to black, the addition was stopped. The solution was sonicated for another 25 minutes, magnetically separated, and washed alternately with deionized water and anhydrous ethanol four times. The solution was vacuum-dried at 95°C for 9 hours to obtain the magnetic boron nitride material.

[0083] When preparing the premix, the ball milling process conditions are: 400 r / min ball milling for 19 hours; the inlet temperature and outlet temperature of the spray drying are 190° C. and 155° C. respectively; the degreasing and reduction process conditions are: 500° C. treatment for 4 hours.

[0084] In step (1), the steel bars are pretreated by mechanically grinding the steel bar surface to expose a bright, fresh metal surface, then degreasing the steel bar using a degreasing solution and then shot blasting the steel bar. The degreasing solution is obtained by mixing a degreasing agent (KX-818, Dongguan Kexin Chemical Co., Ltd.) and water in a mass ratio of 1:18.

[0085] The specific method of degreasing treatment is: immerse the steel bars completely in 75℃ degreasing liquid, keep warm for 18 minutes, take them out and dry them at 105℃ for 9 minutes.

[0086] The specific method of shot blasting is: use a 25kW shot blasting machine to load steel shots with a diameter of 0.7 mm to shot blast the steel bar surface for 15 minutes.

[0087] In step (1), the process conditions of plasma spraying are: spraying distance 90 mm, powder feeding rate 62 g / min, argon flow rate 35 L / min, hydrogen flow rate 8 L / min, current 55 A, and voltage 62 V.

[0088] In step (1), the thickness of the transition layer is 0.3 mm.

[0089] In step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 25 MHz, the magnetic field is 35 Gs, and the treatment time is 35 minutes.

[0090] In step (2), the process conditions of cold spraying are: nitrogen as powder feeding gas, powder feeding rate of 35 g / min, powder feeding gas preheating temperature of 370°C, powder feeding rate of 25 g / min, spraying distance of 25 mm, and cooling rate of 45°C / s.

[0091] In step (2), the thickness of the surface coating is 0.6 mm.

[0092] Comparative Example 1

[0093] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0094] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0095] (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0096] The transition layer was made by mixing 10 kg of silicon powder (325 mesh, Chengdu Keliang Building Materials Co., Ltd.) and 3 kg of zirconium diboride powder (1 μm, Nangong Kejin Welding Materials Co., Ltd.);

[0097] The premix is prepared by the following method: 30 kg of titanium powder (200 mesh, Hebei Ruihuang Metal Materials Co., Ltd.), 20 kg of silicon carbide (200 mesh, Henan Hengxing Metallurgical Materials Co., Ltd.), 20 kg of zirconium carbide (200 mesh, Hubei Xingdongcheng Chemical Co., Ltd.), 1 kg of polyvinyl alcohol (Jinan Jinniu Chemical Co., Ltd.), and 1 kg of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, which is spray-dried to obtain mixed particles, and then degreased and reduced under a hydrogen atmosphere to obtain the obtained product.

[0098] When preparing the premix, the ball milling process conditions are: 300r / min ball milling for 18 hours; the inlet temperature and outlet temperature of the spray drying are 180°C and 150°C respectively; the degreasing and reduction process conditions are: 450°C treatment for 3 hours.

[0099] In step (1), the steel bars are pretreated by mechanically grinding the steel bar surface to expose a bright, fresh metal surface, then degreasing the steel bar using a degreasing solution and then shot blasting the steel bar. The degreasing solution is obtained by mixing a degreasing agent (KX-818, Dongguan Kexin Chemical Co., Ltd.) and water in a mass ratio of 1:15.

[0100] The specific method of degreasing treatment is: immerse the steel bars completely in 70℃ degreasing liquid, keep warm for 15 minutes, take them out and dry them at 100℃ for 8 minutes.

[0101] The specific method of shot blasting is: use a 20kW shot blasting machine to load steel shots with a diameter of 0.6mm to shot blast the steel bar surface for 10 minutes.

[0102] In step (1), the process conditions of plasma spraying are: spraying distance 80 mm, powder feeding rate 60 g / min, argon flow rate 30 L / min, hydrogen flow rate 8 L / min, current 50 A, and voltage 60 V.

[0103] In step (1), the thickness of the transition layer is 0.2 mm.

[0104] In step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 20 MHz, the magnetic field is 30 Gs, and the treatment time is 30 minutes.

[0105] In step (2), the process conditions of cold spraying are: nitrogen as powder feeding gas, powder feeding rate of 30 g / min, powder feeding gas preheating temperature of 350°C, powder feeding rate of 20 g / min, spraying distance of 20 mm, and cooling rate of 40°C / s.

[0106] In step (2), the thickness of the surface coating is 0.5 mm.

[0107] Comparative Example 2

[0108] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0109] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0110] (2) then cold spraying the pre-coated steel bars with the premix to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0111] The transition layer is made of a mixture of 10 kg silicon powder (325 mesh, Chengdu Keliang Building Materials Co., Ltd.), 3 kg zirconium diboride powder (1 μm, Nangong Kejin Welding Materials Co., Ltd.), and 0.1 kg magnetic boron nitride material.

[0112] The premix is prepared by the following method: 30 kg of titanium powder (200 mesh, Hebei Ruihuang Metal Materials Co., Ltd.), 20 kg of silicon carbide (200 mesh, Henan Hengxing Metallurgical Materials Co., Ltd.), 20 kg of zirconium carbide (200 mesh, Hubei Xingdongcheng Chemical Co., Ltd.), 1 kg of polyvinyl alcohol (Jinan Jinniu Chemical Co., Ltd.), and 1 kg of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, which is spray-dried to obtain mixed particles, and then degreased and reduced under a hydrogen atmosphere to obtain the obtained product.

[0113] The magnetic boron nitride material is prepared by the following method:

[0114] (A) adding hexagonal boron nitride to an acid solution 60 times its weight, stirring at 50°C and 1000 rpm for 25 hours, naturally cooling to room temperature (25°C), filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid;

[0115] (B) The intercalated boron nitride was dispersed in an equal amount of isopropanol, ultrasonically treated at 60 kHz and 300 W for 15 hours, centrifuged at 5000 rpm for 30 minutes, and the supernatant was collected, washed with water until neutral, and dried at 90°C for 30 hours to obtain boron nitride nanosheets.

[0116] (C) 0.1 kg of boron nitride nanosheets and 0.2 kg of ferrous chloride tetrahydrate were added to 2 kg of deionized water and ultrasonically treated at 60 kHz and 180 Hz for 3 hours to obtain a boron nitride nanosheet dispersion. 1 kg of a 5 mg / mL sodium hydroxide solution was slowly added dropwise to the boron nitride nanosheet dispersion while stirring. The addition was completed over 30 minutes. Then, a 5 mg / mL hydrogen peroxide solution was added dropwise. When the solution turned from gray-blue to black, the addition was stopped. The solution was ultrasonically treated for another 20 minutes, magnetically separated, and washed alternately with deionized water and anhydrous ethanol three times. The solution was vacuum-dried at 90°C for 8 hours to obtain the magnetic boron nitride material.

[0117] When preparing the premix, the ball milling process conditions are: 300r / min ball milling for 18 hours; the inlet temperature and outlet temperature of the spray drying are 180°C and 150°C respectively; the degreasing and reduction process conditions are: 450°C treatment for 3 hours.

[0118] In step (1), the steel bars are pretreated by mechanically grinding the steel bar surface to expose a bright, fresh metal surface, then degreasing the steel bar using a degreasing solution and then shot blasting the steel bar. The degreasing solution is obtained by mixing a degreasing agent (KX-818, Dongguan Kexin Chemical Co., Ltd.) and water in a mass ratio of 1:15.

[0119] The specific method of degreasing treatment is: immerse the steel bars completely in 70℃ degreasing liquid, keep warm for 15 minutes, take them out and dry them at 100℃ for 8 minutes.

[0120] The specific method of shot blasting is: use a 20kW shot blasting machine to load steel shots with a diameter of 0.6mm to shot blast the steel bar surface for 10 minutes.

[0121] In step (1), the process conditions of plasma spraying are: spraying distance 80 mm, powder feeding rate 60 g / min, argon flow rate 30 L / min, hydrogen flow rate 8 L / min, current 50 A, and voltage 60 V.

[0122] In step (1), the thickness of the transition layer is 0.2 mm.

[0123] In step (2), the process conditions of cold spraying are: nitrogen as powder feeding gas, powder feeding rate of 30 g / min, powder feeding gas preheating temperature of 350°C, powder feeding rate of 20 g / min, spraying distance of 20 mm, and cooling rate of 40°C / s.

[0124] In step (2), the thickness of the surface coating is 0.5 mm.

[0125] Comparative Example 3

[0126] A method for preparing a corrosion-resistant composite metal material for construction, comprising the following specific steps:

[0127] (1) First, plasma spray the steel bar surface to form a transition layer to obtain pre-coated steel bars;

[0128] (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material;

[0129] The transition layer is made of a mixture of 10 kg silicon powder (325 mesh, Chengdu Keliang Building Materials Co., Ltd.), 3 kg zirconium diboride powder (1 μm, Nangong Kejin Welding Materials Co., Ltd.), and 0.1 kg magnetic boron nitride material.

[0130] The premix was obtained by uniformly mixing 30 kg of titanium powder (200 mesh, Hebei Ruihuang Metal Materials Co., Ltd.), 20 kg of silicon carbide (200 mesh, Henan Hengxing Metallurgical Materials Co., Ltd.), and 20 kg of zirconium carbide (200 mesh, Hubei Xingdongcheng Chemical Co., Ltd.).

[0131] The magnetic boron nitride material is prepared by the following method:

[0132] (A) adding hexagonal boron nitride to an acid solution 60 times its weight, stirring at 50°C and 1000 rpm for 25 hours, naturally cooling to room temperature (25°C), filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid;

[0133] (B) The intercalated boron nitride was dispersed in an equal amount of isopropanol, ultrasonically treated at 60 kHz and 300 W for 15 hours, centrifuged at 5000 rpm for 30 minutes, and the supernatant was collected, washed with water until neutral, and dried at 90°C for 30 hours to obtain boron nitride nanosheets.

[0134] (C) 0.1 kg of boron nitride nanosheets and 0.2 kg of ferrous chloride tetrahydrate were added to 2 kg of deionized water and ultrasonically treated at 60 kHz and 180 Hz for 3 hours to obtain a boron nitride nanosheet dispersion. 1 kg of a 5 mg / mL sodium hydroxide solution was slowly added dropwise to the boron nitride nanosheet dispersion while stirring. The addition was completed over 30 minutes. Then, a 5 mg / mL hydrogen peroxide solution was added dropwise. When the solution turned from gray-blue to black, the addition was stopped. The solution was ultrasonically treated for another 20 minutes, magnetically separated, and washed alternately with deionized water and anhydrous ethanol three times. The solution was vacuum-dried at 90°C for 8 hours to obtain the magnetic boron nitride material.

[0135] In step (1), the steel bars are pretreated by mechanically grinding the steel bar surface to expose a bright, fresh metal surface, then degreasing the steel bar using a degreasing solution and then shot blasting the steel bar. The degreasing solution is obtained by mixing a degreasing agent (KX-818, Dongguan Kexin Chemical Co., Ltd.) and water in a mass ratio of 1:15.

[0136] The specific method of degreasing treatment is: immerse the steel bars completely in 70℃ degreasing liquid, keep warm for 15 minutes, take them out and dry them at 100℃ for 8 minutes.

[0137] The specific method of shot blasting is: use a 20kW shot blasting machine to load steel shots with a diameter of 0.6mm to shot blast the steel bar surface for 10 minutes.

[0138] In step (1), the process conditions of plasma spraying are: spraying distance 80 mm, powder feeding rate 60 g / min, argon flow rate 30 L / min, hydrogen flow rate 8 L / min, current 50 A, and voltage 60 V.

[0139] In step (1), the thickness of the transition layer is 0.2 mm.

[0140] In step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 20 MHz, the magnetic field is 30 Gs, and the treatment time is 30 minutes.

[0141] In step (2), the process conditions of cold spraying are: nitrogen as powder feeding gas, powder feeding rate of 30 g / min, powder feeding gas preheating temperature of 350°C, powder feeding rate of 20 g / min, spraying distance of 20 mm, and cooling rate of 40°C / s.

[0142] In step (2), the thickness of the surface coating is 0.5 mm.

[0143] Test example

[0144] The corrosion resistance of the composite metal materials obtained in Examples 1-3 and Comparative Examples 1-3 was tested using the method described in YB / T4367-2014, "Test Method for Corrosion of Steel Bars in Chloride Ion Environments." A 2% sodium chloride solution was circulated for 72 hours, and the corrosion rate was measured. Adhesion of the composite metal materials was tested using the pull-off method. Failure was observed at the interface between the coating and the substrate, and at the composite coating.

[0145] The test results are shown in Table 1.

[0146] Table 1. Performance test results

[0147] <![CDATA[Corrosion rate (g / (m 2 ·h))]]> <![CDATA[Adhesion force (kg / cm 2 ).]]> Example 1 ≤0.01 248 Example 2 ≤0.01 251 Example 3 ≤0.01 255 Comparative Example 1 0.89 225 Comparative Example 2 1.23 210 Comparative Example 3 1.58 201

[0148] As can be seen from Table 1, the composite metal materials obtained in Examples 1 to 3 have low corrosion rates, good corrosion resistance, high adhesion, long-term corrosion resistance, and long service life.

[0149] In Comparative Example 1, the magnetic boron nitride material was omitted when spraying the transition layer, and in Comparative Example 2, the alternating magnetic field treatment was omitted. The premix of Comparative Example 3 was prepared by a direct mixing method. Both the corrosion resistance and adhesion were significantly deteriorated, indicating that the transition layer and the surface coating have a synergistic effect, which improves the long-term corrosion resistance of the composite metal material.

[0150] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A method for preparing a corrosion-resistant composite metal material for construction, characterized in that: The specific steps are as follows: (1) First, plasma spray the steel bar surface to form a transition layer to obtain a pre-coated steel bar; (2) then subjecting the pre-coated steel bars to an alternating magnetic field treatment, and cold spraying the premixed material to form a surface coating, thereby obtaining the corrosion-resistant composite metal material; The transition layer is made of silicon powder, zirconium diboride powder and magnetic boron nitride material in a mass ratio of 10:3-4:0.1-0.2; The premix is prepared by the following method, in parts by weight: 30 to 40 parts of titanium powder, 20 to 30 parts of silicon carbide, 20 to 30 parts of zirconium carbide, 1 to 1.5 parts of polyvinyl alcohol, and 1 to 1.5 parts of polyethylene glycol 400 are mixed and ball-milled to obtain a mixed slurry, spray-dried to obtain mixed particles, and degreased and reduced under a hydrogen atmosphere to obtain the premix; The magnetic boron nitride material is prepared by the following method: (A) adding hexagonal boron nitride to an acid solution 60 to 70 times its weight, stirring at 50 to 60° C. and 1000 to 2000 r / min for 25 to 35 hours, naturally cooling to room temperature, filtering out the solid, and washing with water until neutral to obtain intercalated boron nitride; wherein the acid solution is obtained by mixing equal volumes of 98% concentrated sulfuric acid and 95% concentrated nitric acid; (B) dispersing the intercalated boron nitride in an equal amount of isopropanol, ultrasonically oscillating the mixture at 60-80 kHz and 300-500 W for 15-20 hours, centrifuging the mixture at 5000-6000 rpm for 30-40 minutes, collecting the supernatant, washing the mixture with water until neutral, and drying the mixture at 90-100° C. for 30-40 hours to obtain boron nitride nanosheets; (C) adding boron nitride nanosheets and ferrous chloride tetrahydrate to deionized water, ultrasonically treating them at 60-80kHz and 180W-200W for 3-5 hours to obtain a boron nitride nanosheet dispersion, slowly adding a 5 mg / mL sodium hydroxide solution to the boron nitride nanosheet dispersion while stirring, and completing the addition over 30 minutes, then adding a 5 mg / mL hydrogen peroxide solution dropwise, and stopping the addition when the solution changes from gray-blue to black, and ultrasonically treating them for 20-30 minutes, magnetically separating them, washing them alternately with deionized water and anhydrous ethanol for 3-4 times, and vacuum drying them at 90-100°C for 8-10 hours to obtain the magnetic boron nitride material; wherein the mass ratio of the boron nitride nanosheets, ferrous chloride tetrahydrate, deionized water, and sodium hydroxide solution is 1:2-3:20-30:10-12; In step (2), the process conditions of the alternating magnetic field treatment are: the magnetic field alternating frequency is 20 to 30 MHz, the magnetic field is 30 to 40 Gs, and the treatment time is 30 to 40 minutes.

2. The preparation method according to claim 1, characterized in that When preparing the premix, the ball milling process conditions are: 300-400 r / min ball milling for 18-20 hours; the inlet temperature and outlet temperature of the spray drying are 180-200°C and 150-160°C respectively; the degreasing and reduction process conditions are: 450-550°C treatment for 3-4 hours.

3. The preparation method according to claim 1, characterized in that In step (1), the steel bar is pretreated, specifically by mechanically grinding the steel bar surface to expose a bright fresh metal surface, then degreasing the steel bar with a degreasing solution, and then shot blasting the steel bar.

4. The preparation method according to claim 1, characterized in that In step (1), the process conditions of plasma spraying are: spraying distance 80-100 mm, powder feeding rate 60-65 g / min, argon flow rate 30-40 L / min, hydrogen flow rate 8-9 L / min, current 50-60 A, and voltage 60-65 V.

5. The preparation method according to claim 1, characterized in that In step (1), the thickness of the transition layer is 0.2 to 0.3 mm.

6. The preparation method according to claim 1, characterized in that In step (2), the process conditions of cold spraying are: nitrogen is used as the powder feeding gas, the powder feeding rate is 30-40 g / min, the powder feeding gas preheating temperature is 350°C-400°C, the powder feeding rate is 20-30 g / min, the spraying distance is 20-30 mm, and the cooling rate is 40-50°C / s.

7. The preparation method according to claim 1, characterized in that In step (2), the thickness of the surface coating is 0.5 to 0.7 mm.

8. A corrosion-resistant composite metal material for construction, characterized in that: The invention is obtained by the preparation method according to any one of claims 1 to 7.