阅读说明：本技术 一种涂层及其制备方法 (Coating and preparation method thereof ) 是由 曾德长 刘孝青 邱兆国 郑志刚 王刚 于 2020-12-15 设计创作，主要内容包括：本发明公开了一种涂层,所述涂层由喷涂粉末喷涂而成,所述喷涂粉末由CNTs粉末和TiB-2-Fe基复合粉末组成。该涂层同时具有优异的硬度、断裂韧性和耐磨性能,能对铁基材料起到很好的防护作用。(The invention discloses a coating which is formed by spraying powder, wherein the spraying powder comprises CNTs powder and TiB 2 -Fe-based composite powder composition. The coating has excellent hardness, fracture toughness and wear resistance, and can play a good protection role on iron-based materials.)

1. A spray powder characterized by: the spraying powder consists of CNTs powder and TiB₂-Fe-based composite powder composition.

2. A spray powder according to claim 1, wherein: the spraying powder comprises 95-99.5 wt% of TiB by mass percent₂-Fe-based composite powder and 0.5-5 wt% of CNTs powder.

3. A spray powder according to claim 1, wherein: the TiB₂-Fe-based composite powder by massThe alloy comprises 21-39 wt% of Fe, 26.1-44.6 wt% of Ti, 12.2-22.7 wt% of B, 6.3-11.7 wt% of Cr, 3.2-5.9 wt% of Ni, 1.4-2.6 wt% of Si, 0.7-1.3 wt% of Mo, 0.7-1.3 wt% of C and 0.53-0.98 wt% of Mn.

4. A spray powder according to claim 1, wherein: the TiB₂The particle size of the Fe-based composite powder is 1-10 mu m, the purity of the CNTs powder is more than or equal to 95%, the tube diameter is 5-20 nm, and the length is 10-30 mu m.

5. A method for producing the spray powder according to any one of claims 1 to 4, characterized in that: the method comprises the following steps:

(1) mixing TiB₂Adding the composite powder of the Fe-based composite powder and the CNTs powder into a ball mill for ball milling and mixing, and then sending the mixed powder into a spray dryer for spray granulation to obtain composite spherical powder;

(2) and carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder.

6. The method for producing a spray powder according to claim 5, characterized in that: the ball milling conditions in the step (1) are as follows: the rotating speed is 250-350 r/min; stopping the ball mill for 15-20 min every time when the ball mill is milled for 25-35 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: (1.5-2) matching and mixing; the ball milling medium is 3-10% of absolute ethyl alcohol.

7. The method for producing a spray powder according to claim 5, characterized in that: the spray granulation conditions in step (1) are as follows: the tower entering temperature is 170-200 ℃; the temperature of the discharged tower is 50-70 ℃; the rotation speed (frequency) is 180-230 Hz.

8. The method for producing a spray powder according to claim 5, characterized in that: the plasma spheroidizing conditions in the step (2) are as follows: the flow rate of the powder is 10-20 g/min; the rotating speed of the powder feeder is 10-15 rpm; the plasma power is 25-35 Kw; the powder feeding gap is 0.3-0.6 mm, and the working atmosphere is rare gas.

9. A coating, characterized by: the coating is sprayed from the spray powder of any one of claims 1 to 4.

10. A method of preparing the coating of claim 9, wherein: the method comprises the following steps:

(1) carrying out oil removal, coarsening and preheating treatment on the iron-based surface;

(2) and depositing the spray powder on the surface of the iron base by adopting an active combustion high-speed gas spraying technology to obtain a coating.

Technical Field

The invention belongs to the technical field of metal ceramic composite coatings, and particularly relates to a coating and a preparation method thereof.

Background

Research reports that over 80% of mechanical parts fail usually due to surface wear and corrosion, and annual losses to the country can reach over 10% of the total value of national production. Therefore, the surface of the common structural member is coated with a wear-resistant corrosion-resistant coating through various surface engineering technologies, so that the safety and reliability of the common structural member in service can be improved, the service life of the common structural member is prolonged, considerable economic benefit is brought, and the common structural member can recover the size and regenerate the size under the condition of size reduction caused by abrasion corrosion or processing out-of-tolerance. Thermal spraying is an important surface protection technology, and various functional coatings prepared by the thermal spraying are widely applied to the fields of aerospace, metallurgy, machinery, papermaking, petrochemical industry and the like. The medium carbon steel has low cost and good comprehensive performance, is an iron-based material with extremely large consumption in industrial manufacture, for example, 45 steel is widely applied to motorcycles and automobiles, and particularly connecting rods, bolts, gears and shaft parts which work under alternating load. Therefore, in order to protect an iron-based coating, such as medium carbon steel, from wear, it is necessary to apply a coating layer on the surface of the iron-based coating, but it is difficult to achieve excellent hardness, fracture toughness, and wear resistance at the same time.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the coating and the preparation method thereof provided by the invention have the advantages that the coating has excellent hardness, fracture toughness and wear resistance, and can play a good protection role on the iron-based material.

The technical purpose of the invention is realized by the following technical scheme:

the spraying powder consists of CNTs powder and TiB₂-Fe-based composite powder composition.

Preferably, the spraying powder comprises 95-99.5 wt% of TiB in percentage by mass₂-Fe-based composite powder and 0.5-5 wt% of CNTs powder.

Preferably, the TiB₂The Fe-based composite powder comprises, by mass, 21 to 39 wt% of Fe, 26.1 to 44.6 wt% of Ti, 12.2 to 22.7 wt% of B, 6.3 to 11.7 wt% of Cr, 3.2 to 5.9 wt% of Ni, 1.4 to 2.6 wt% of Si, 0.7 to 1.3 wt% of Mo, 0.7 to 1.3 wt% of C, and 0.53 to 0.98 wt% of Mn.

Preferably, the TiB₂The particle size of the Fe-based composite powder is 1-10 mu m, the purity of the CNTs powder is more than or equal to 95%, the tube diameter is 5-20 nm, and the length is 10-30 mu m.

A method of preparing a spray powder as described above, comprising the steps of:

(1) mixing TiB₂Adding the composite powder of the Fe-based composite powder and the CNTs powder into a ball mill for ball milling and mixing, and then sending the mixed powder into a spray dryer for spray granulation to obtain composite spherical powder;

(2) and carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder.

Preferably, the ball milling conditions in step (1) are as follows: the rotating speed is 250-350 r/min; stopping the ball mill for 15-20 min every time when the ball mill is milled for 25-35 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: (1.5-2) matching and mixing; the ball milling medium is 3-10% of absolute ethyl alcohol.

A further preferred ball milling medium is 5% absolute ethanol.

Preferably, the spray granulation conditions in step (1) are: the tower entering temperature is 170-200 ℃; the temperature of the discharged tower is 50-70 ℃; the rotation speed (frequency) is 180-230 Hz.

Preferably, the plasma spheroidizing conditions in the step (2) are as follows: the flow rate of the powder is 10-20 g/min; the rotating speed of the powder feeder is 10-15 rpm; the plasma power is 25-35 Kw; the powder feeding gap is 0.3-0.6 mm, and the working atmosphere is rare gas.

The coating is formed by spraying the spraying powder.

A method for preparing a coating as described above, comprising the steps of:

(1) carrying out oil removal, coarsening and preheating treatment on the iron-based surface;

(2) and depositing the spray powder on the surface of the iron base by adopting an active combustion high-speed gas spraying technology to obtain a coating.

Preferably, the specific steps of step (1) are as follows: the method comprises the steps of ultrasonically cleaning an iron-based surface by using acetone, then carrying out sand blasting and coarsening on the iron-based surface by using 24-80 # white corundum until the roughness Ra of the iron-based surface is 3-5 mu m, and then preheating the iron-based surface to 100-150 ℃.

Preferably, the conditions of the active combustion high-speed gas spraying in the step (2) are as follows: the fuel is propane, the pressure of the fuel I is 97-117 Psi, the pressure of the fuel II is 102-108 Psi, the air pressure is 105-108 Psi, the nitrogen powder feeding flow is 70-80L/min, the powder feeding rate is 10-30%, the spraying distance is 280-360 mm, and the spraying angle is 80-90 degrees.

The invention adopts the TiB doped with the carbon nano tube₂-Fe-based composite powder as iron-based surface protective coating material, wherein the component is TiB₂The hard phase has high hardness of 34GPa and good oxidation resistance below 1000 GPa, and plays a role in stabilizing tissues and resisting wear in the coating; the Fe-based alloy is used as a bonding phase of the coating, an austenite phase and a ferrite phase of the coating have better strength and toughness, wherein Ni and Cr elements can generate compact oxides at high temperature, the coating can be protected from failure to a certain extent, and C and B elements can form carbides and borides with alloy elements so as to improve the antifriction property of the coating; the uniform dispersion and high thermal conductivity (about 3000W/m.K) of the CNTs can enable the spray powder and the coating to achieve a more sufficient melting state and bonding strength, the low expansion coefficient of the CNTs can reduce thermal stress caused by thermal mismatch, and the ultrahigh elastic modulus and strength of the CNTs can further improve the fracture toughness and hardness of the coating, so that the coating is effectively prevented from generating cracks and losing efficacy under the abrasion working condition.

In order to avoid the oxidation of the composite powder particles during ball milling, the powder preparation needs to be carried out in a glove box; in order to make the powder composite evenly and prevent the cooling of the ball milling process, 5 percent of absolute ethyl alcohol is added as a ball milling medium.

The invention has the beneficial effects that:

(1) the coating disclosed by the invention can be well combined with a matrix, has extremely high fracture toughness and wear resistance, has better oxidation resistance and corrosion resistance, and can obviously prolong the service life of medium carbon steel such as 45 steel.

(2) The coating disclosed by the invention is low in raw material cost, stable in preparation process and obvious in performance improvement effect, and can provide a good protection or repair effect for the iron-based surface.

(3) The coating of the invention has few harmful elements, is beneficial to the environment and relates to the application of the coating in the fields of food processing and the like.

(4) Compared with the traditional spraying method, the active combustion high-speed gas spraying technology is adopted in the preparation process of the coating, and due to the lower flame temperature and higher flame flow speed, the oxidation of the spraying powder is reduced, the coating obtains higher surface pressure stress during deposition, and the coating with high bonding strength, low porosity and high wear resistance can be prepared.

Drawings

FIG. 1 HRSEM topography of the surface of composite spherical powder containing 1.5 wt% CNTs prepared by spray drying of example 3.

FIG. 2 SEM image of a cross-section of the spray powder prepared in example 3.

FIG. 3 HRSEM topography for the spray powder prepared in example 3.

FIG. 4 particle size distribution diagram of the spray powder prepared in example 3.

FIG. 5 sectional HRSEM of the coating prepared in example 4.

FIG. 6A 300g Vickers indentation topography of the coating prepared in example 4

FIG. 7 HRSEM topography for the scratch wear region of the coating prepared in example 4.

Detailed Description

The present invention will be further described with reference to the following specific examples.

Example 1:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 99.5 wt% of TiB₂-Fe-based composite powder and 0.5 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 21 wt% of Fe, 43.47 wt% of Ti, 22.7 wt% of B, 6.3 wt% of Cr, 3.2 wt% of Ni, 1.4 wt% of Si, 0.7 wt% of Mo, 0.7 wt% of C and 0.53 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 1 μm. The CNTs powder has a purity of 95%, a tube diameter of 5nm and a length of 10 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 4 h; the ball milling speed is 250 r/min; stopping the ball milling for 20min every 30 min; the grinding balls have diameters of 10mm, 8mm and 5mm according toThe mass ratio is 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 230 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 5 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 70L/min, the powder feeding rate is 10%, the spraying distance is 280mm, and the spraying angle is 90 degrees.

Example 2:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 99 wt% of TiB₂-Fe-based composite powder and 1 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 39 wt% of Fe, 26.1 wt% of Ti, 12.2 wt% of B, 10.62 wt% of Cr, 5.9 wt% of Ni, 2.6 wt% of Si, 1.3 wt% of Mo, 1.3 wt% of C and 0.98 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 10 μm. The purity of the CNTs powder is 97%, the tube diameter is 20nm, and the length is 30 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling rotating speed is 300 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. Then mixing the mixtureAnd (4) feeding the slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 4 mu m, and finally preheating to 100 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 107Psi, the pressure of the fuel II is 105Psi, the air pressure is 105Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 320mm, and the spraying angle is 85 degrees.

Example 3:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 98.5 wt% of TiB₂-Fe-based composite powder and 1.5 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 22.5 wt% of Fe, 44.6 wt% of Ti, 13.52 wt% of B, 11.7 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 6 μm. The purity of the CNTs powder is 98%, the tube diameter is 16nm, and the length is 25 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 4 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: intoThe tower temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 180 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3.6 mu m, and finally preheating to 130 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 102Psi, the air pressure is 105Psi, the powder feeding flow of nitrogen is 80L/min, the powder feeding rate is 25%, the spraying distance is 360mm, and the spraying angle is 85 degrees.

Example 4:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 98 wt% of TiB₂-Fe-based composite powder and 2 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Example 5:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 97.5 wt% of TiB₂-Fe-based composite powder and 2.5 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Example 6:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 97 wt% of TiB₂-Fe-based composite powder and 3 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Example 7:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 96.5 wt% of TiB₂-Fe-based composite powder and 3.5 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Example 8:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 96 wt% of TiB₂-Fe-based composite powder and 4 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Example 9:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 95.5 wt% of TiB₂-Fe-based composite powder and 4.5 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Example 10:

the coating is formed by spraying powder, wherein the spraying powder is TiB doped with CNTs powder₂-Fe-based composite powder. The spraying powder comprises 95 wt% of TiB₂-Fe-based composite powder and 5 wt% CNTs powder. Wherein TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm. The purity of the CNTs powder is 99%, the tube diameter is 12nm, and the length is 22 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder and CNTs powder into a high-energy ball mill for ball milling for 6 h; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Comparative example 1:

the coating is formed by spraying TiB powder₂-Fe-based composite powder. TiB₂The Fe-based composite powder was composed of 26.1 wt% of Fe, 43.2 wt% of Ti, 13.52 wt% of B, 9.5 wt% of Cr, 3.8 wt% of Ni, 1.6 wt% of Si, 0.8 wt% of Mo, 0.8 wt% of C and 0.68 wt% of Mn. TiB₂The particle diameter of the Fe-based composite powder was 8 μm.

The preparation method of the coating comprises the following steps:

(1) firstly, the prepared TiB₂Adding Fe-based composite powder into a high-energy ball mill for ball milling for 6 hours; the ball milling speed is 350 r/min; stopping the ball milling for 20min every 30 min; the grinding ball has the diameter of 10mm, 8mm and 5mm, and is prepared by mixing the following raw materials in a mass ratio of 1: 1: 2, matching according to a proportion; and 5% absolute ethanol was added. And then sending the mixed slurry powder into a spray dryer for granulation to obtain the composite spherical powder. The granulation parameters are as follows: the tower entering temperature is 180 ℃; the temperature of the discharged tower is 60 ℃; the rotational speed (frequency) was 210 Hz.

(2) Carrying out plasma spheroidizing treatment on the composite spherical powder to obtain sprayable spraying powder, wherein the flow rate of the powder is 15 g/min; the rotating speed of the powder feeder is 13 rpm; the plasma power is 30 Kw; the powder feeding gap is 0.5mm, and the working atmosphere is Ar gas.

(3) And (3) carrying out acetone ultrasonic cleaning on the surface of the 45 steel, then carrying out sand blasting and coarsening by using No. 24-80 white corundum until the surface roughness Ra is 3 mu m, and finally preheating to 150 ℃.

(4) And depositing the spray powder on the surface of the 45 steel by adopting an active combustion high-speed gas spraying technology to obtain a coating. The spraying process parameters are as follows: the fuel type is propane, the pressure of the fuel I is 117Psi, the pressure of the fuel II is 108Psi, the air pressure is 108Psi, the powder feeding flow of nitrogen is 75L/min, the powder feeding rate is 20%, the spraying distance is 340mm, and the spraying angle is 90 degrees.

Test example:

1. hardness and fracture toughness testing: in the experiment, the hardness and the fracture toughness of the cross section of the coating are tested and calculated by adopting a micro-indentation method, the test equipment is an HVS-1000 type Vickers hardness tester, the loading load is 300g, and the load-holding time is 15 s.

2. And (3) testing the frictional wear performance: the sample test is carried out on an SFT-2M pin-disc friction abrasion tester, a friction pair is a Si3N4 ceramic ball with the diameter of 4mm, the test load is 16N, the friction speed is 0.1M/s, the rotation radius is 3mm, and the abrasion time is 30 min.

The results of the performance tests on the coatings of the examples and comparative examples are shown in table 1.

Table 1: results of coating Performance testing

As can be seen from the data in the table, the coating of the invention has excellent hardness, fracture toughness and wear resistance, and the hardness of the coating can reach 834 +/-51 HV_0.3Above, the highest can reach 920 +/-43 HV_0.3(ii) a The fracture toughness of the coating reaches 2.14 +/-0.3 MPa.m^1/2And above, the highest can reach 3.38 +/-0.1 MPa.m^1/2(ii) a The wear rate of the coating can be reduced to 7.95 x 10^{- 6}mm³a/N.m and below, at least 2.46X 10^-6mm³N · m; compared with the comparative ratio 1, the hardness, the fracture toughness and the wear resistance of the coating are greatly improved, so that the coating prepared by the method can play a good role in protecting 45 steel.

Furthermore, it can be seen from FIG. 1 that the added CNTs can be uniformly dispersed into TiB by spray-drying granulation₂The surface of the Fe-based composite powder creates favorable conditions for later spraying to develop its high thermal conductivity.

FIGS. 2 and 3 illustrate TiB after plasma spheroidization₂The ceramic phase is uniformly embedded into the composite powder, and the granulated CNTs are reserved; the composite spraying powder has good agglomeration and sphericity, and compact interior and surface, which is favorable for later useAnd continuously preparing the coating by active combustion high-speed gas spraying.

Figure 4 shows that the spheroidized composite powder particle size is suitable for spray powder.

Further observation of the cross-sectional morphology of the coating (as shown in fig. 5) revealed that the coating prepared by the present invention has a dense and uniform texture and good bonding of the coating to the substrate, wherein the doping phases are uniformly distributed and there are no significant micro-cracks and void defects, which indicates that the overall quality of the coating is excellent.

The microscopic indentation size of fig. 6 shows that the hardness of the coating is extremely high, and no obvious cracks or deformation are formed around the indentation, which shows that the fracture toughness of the coating doped with 2 wt% of CNTs is remarkably improved.

The HRSEM morphology of the wear region of FIG. 7 shows that the wear scar width and depth of the coating after the friction test is small, no obvious large holes and flaking phenomenon exist, the wear is mainly oxidation and abrasive wear, and the adhesive wear is very light. Therefore, the coating prepared by the method can improve the abrasion and fracture failure of 45 steel carbon steel under the actual application working condition and prolong the service life of the 45 steel carbon steel.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.