High-strength and high-corrosion-resistance photovoltaic support steel and preparation method thereof

Abstract

The invention discloses high-strength and high-corrosion-resistance steel for a photovoltaic support, the steel for the photovoltaic support is composed of 95-98 wt% of a steel matrix and 2-5 wt% of high-entropy carbide ceramic nanoparticles, the surface of the steel is provided with three layers of high-entropy amorphous alloy gradient coatings, and the steel matrix comprises the following components: 1.25-1.65 wt% of Mn, 0.25-0.45 wt% of Ni, 0.15-0.22 wt% of C, 0.05-0.15 wt% of Ti, less than or equal to 0.05 wt% of Si and the balance of Fe; the high-entropy carbide ceramic is prepared from the following components: 0.15 to 0.25 percent of Ti, 0.15 to 0.25 percent of V, 0.15 to 0.25 percent of Nb, 0.15 to 0.25 percent of La, 0.15 to 0.25 percent of Y and C, wherein the particle size of nano particles is 200 to 500 nm; the inner coating comprises the following components: Fe (30-35) Cr (10-15) Ni (5-15) Mo (5-15) Gd (5-15) B (20-30), and the thickness of the inner coating is 10-20 microns; the middle coating comprises the following components: 20-25 parts of Fe, 20-25 parts of Cr, 5-15 parts of Ni, 5-15 parts of Mo, 5-15 parts of Gd and 20-30 parts of B, and the thickness of the coating is 20-30 microns; and the outer coating comprises the following components: Fe (10-15) Cr (30-35) Ni (5-15) Mo (5-15) Gd (5-15) B (20-30), and the thickness of the coating is 30-40 [mu] m. The corrosion-resistant photovoltaic support material has high strength, high hardness and excellent corrosion resistance, and has a good application prospect in the field of photovoltaic support materials.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and particularly to a steel for high-strength and highly corrosion-resistant photovoltaic brackets. Background Art

[0002] As low-carbon new energy has been paid more and more attention, especially photovoltaic power generation, as an important renewable new energy, has been widely recognized in the market and its demand is continuously increasing. As a key component in the solar photovoltaic power generation system, the photovoltaic bracket is used to support and fix the photovoltaic modules to ensure the stable operation of the photovoltaic panels in various natural environments. Most of the photovoltaic brackets are installed on hillsides, wildernesses, deserts, etc., and need to withstand the impact of extreme environments and climatic conditions. In order to ensure the stability, durability and economy of the brackets, the materials of the photovoltaic brackets usually need to meet the following conditions: having sufficient strength to withstand the weight of the photovoltaic modules and other loads; having good corrosion resistance to withstand the erosion of chemical substances; having good weather resistance to reduce the influence of the outdoor environment on the material properties. In addition, it is also desirable that the material has good processability, dimensional stability and economy, etc. In order to ensure the quality and long-term stability of the photovoltaic brackets, it is an urgent problem to balance the high strength and high corrosion and weather resistance of the photovoltaic bracket materials, so it is necessary to further develop new photovoltaic bracket materials. Summary of the Invention

[0003] Technical problem to be solved: The technical problem to be solved by the present invention is to provide a steel for high-strength photovoltaic brackets.

[0004] Technical solution: A steel for high-strength and highly corrosion-resistant photovoltaic brackets is composed of 95-98 wt% of a steel matrix and 2-5 wt% of high-entropy carbide ceramic nanoparticles, and has three-layer gradient coatings on the surface. Preferably, the preparation method of the steel for high-strength and highly corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion and heat it to the molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt and mechanically stir until the particles are evenly distributed, and pour it into a mold for forming; S3. Clean, sandblast and preheat the formed steel, perform plasma spraying and use compressed air for rapid cooling until the three-layer gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment to obtain the steel for high-strength and highly corrosion-resistant photovoltaic brackets. Preferably, the heating temperature in step S1 is 1570-1590 °C. Preferably, the heat treatment temperature in step S4 is 440-460 °C, and the heat treatment time is 20-60 min. Preferably, the composition of the steel matrix consists of the following weight percentages: Mn: 1.25 - 1.65 wt%, Ni: 0.25 - 0.45 wt%, C: 0.15 - 0.22 wt%, Ti: 0.05 - 0.15 wt%, Si: ≤ 0.05 wt%, and the balance is Fe. Preferably, the composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.15-0.25 V 0.15-0.25 Nb 0.15- 0.25 La 0.15-0.25 Y 0.15-0.25 )C, and the particle size is 200 - 500 nm. Preferably, the preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder in proportion, put them into a ball milling tank, fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate it, heat it to carry out a carbothermal reduction reaction and cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, perform ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm. Preferably, the heating rate in step S12 is 10 - 20 °C / min, and the heating temperature is 1800 - 2000 °C. Preferably, the three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30-35 Cr 10-15 Ni 5-15 Mo 5-15 Gd 5-15 B 20-30 , and the coating thickness is 10 - 20 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20-25 Cr 20-25 Ni 5-15 Mo 5-15 Gd 5-15 B 20-30 , and the coating thickness is 20 - 30 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10-15 Cr 30-35 Ni 5-15 Mo 5-15 Gd 5-15 B 20-30, the coating thickness is 30 - 40 μm. Beneficial effects: Compared with the prior art, the present invention has the following characteristics: The present invention improves the strength of the steel matrix by using the microalloying method, adds high-entropy carbide ceramic nanoparticles as the reinforcing phase to improve the comprehensive mechanical properties of the material, and sprays a high-entropy amorphous alloy gradient coating on the surface of the material to effectively improve the corrosion resistance and weather resistance of the material. At present, 235MPa and 350MPa grade steels are generally used for forming the photovoltaic support structure, which is not conducive to reducing the consumption of steel. By adding elements such as Ti and Ni to the steel for microalloying treatment, Ti is a strong carbide-forming element that can combine with carbon to form stable titanium carbide, which helps to refine the grains of the steel, thereby improving the strength of the steel; Ni helps to refine the grains, which can not only improve the strength and toughness of the alloy, but also improve the corrosion resistance of the steel matrix. In addition to metal elements that can refine grains, transition metal carbides, rare earth elements, etc. can also inhibit grain growth. By adding high-entropy carbide ceramics containing rare earth elements to the matrix, compared with traditional carbide ceramics, the high-entropy effect makes the ceramics exhibit excellent properties such as high modulus, high hardness, and good oxidation resistance. As the reinforcing phase, it can not only refine grains, improve the strength and toughness of the matrix, but also improve the hardness and thermal stability of the alloy, making the alloy have excellent comprehensive properties. Both high-entropy alloys and amorphous alloys have excellent mechanical properties, and amorphous alloys have good wear resistance and corrosion resistance. According to the Inoue's three principles, introducing the concept of high entropy into the amorphous alloy can increase the degree of disorder of the alloy system, thereby improving the amorphous formation ability of the alloy. Using the high-entropy amorphous alloy as the coating, the coating has high thermal stability and can effectively improve the strength, hardness, corrosion resistance and wear resistance of the alloy. In order to improve the density of the coating and the bonding force with the matrix, the coating is prepared into a gradient structure. The inner layer with more Fe content can form a stronger bonding force with the Fe matrix and has fewer structural defects; as the composition transitions to the outer layer, due to the higher Cr content, the corrosion resistance is further improved. The entire composition gradient coating reduces the temperature gradient between the matrix and the coating, prevents large stresses from appearing on the surface of the coating, and can prevent the generation of microcracks, effectively improving the density and stability of the coating. In addition, by performing low-temperature relaxation treatment on the coating, the free volume in the amorphous structure is reduced, the internal atomic spacing is shortened, and the bonding strength between atoms is increased, which can further improve the density of the coating, reduce the porosity, improve the hydrophobicity and passivation ability of the coating surface, and further improve the corrosion resistance of the coating. Compared with the prior art, the present invention has the following advantages and positive effects: In the present invention, high-entropy carbide ceramic nanoparticles are added to the steel matrix as reinforcement phases, which can effectively improve the mechanical properties of the material. In the present invention, a high-entropy amorphous alloy coating is sprayed on the surface of the material, which can effectively improve the corrosion resistance and surface mechanical properties of the material. In the present invention, a three-layer gradient coating is prepared on the surface of the material, which can enhance the bonding force between the material and the coating and improve the density of the coating. Detailed Embodiments To further understand the present invention, the preferred embodiments of the present invention will be described below in conjunction with examples. The specific preferred examples are as follows: Example 1: A steel for high-strength and highly corrosion-resistant photovoltaic brackets is composed of 98 wt% of a steel matrix and 2 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the steel for high-strength and highly corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the ratio, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour them into a mold for molding; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and quickly cool it with compressed air until the three-layer gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and highly corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.25 wt%, Ni: 0.45 wt%, C: 0.18 wt%, Ti: 0.09 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the ratio, put them into a ball milling tank, fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramic into a ball milling jar, conduct ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 2: A high-strength and highly corrosion-resistant steel for photovoltaic brackets is composed of 97 wt% of a steel matrix and 3 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the high-strength and highly corrosion-resistant steel for photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix in proportion and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt and mechanically stir until the particles are evenly distributed, and pour it into a mold for molding; S3. Clean, sandblast and preheat the formed steel, conduct plasma spraying and rapidly cool it with compressed air until the three-layer gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the high-strength and highly corrosion-resistant steel for photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.65 wt%, Ni: 0.33 wt%, C: 0.21 wt%, Ti: 0.15 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb0.20 La 0.20 Y 0.20 ) C, the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder in proportion, put them into a ball milling jar, fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate it, heat it to carry out a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain a high-entropy carbide ceramic; S13. Put the high-entropy carbide ceramic into a ball milling jar, perform ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 3: A high-strength and highly corrosion-resistant steel for photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the high-strength and highly corrosion-resistant steel for photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix in proportion and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, mechanically stir until the particles are evenly distributed, and pour it into a mold for forming; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and use compressed air for rapid cooling until the three-layer gradient coating is sprayed; S4. Put the steel with the sprayed coating into a heat treatment furnace for low-temperature relaxation treatment. The heat treatment temperature is 450 °C and the heat treatment time is 40 min to obtain the steel for high-strength and high-corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.57 wt%, Ni: 0.25 wt%, C: 0.16 wt%, Ti: 0.06 wt%, Si: 0.02 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder according to the ratio, put them into a ball milling tank, fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B25 , the coating thickness is 35 μm. Example 4: A steel for high-strength and highly corrosion-resistant photovoltaic brackets is composed of 95 wt% of a steel matrix and 5 wt% of high-entropy carbide ceramic nanoparticles, and has three-layer gradient coatings on the surface; The preparation method of the steel for high-strength and highly corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the ratio, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour it into a mold for molding; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and rapidly cool it with compressed air until the three-layer gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and highly corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.47 wt%, Ni: 0.30 wt%, C: 0.22 wt%, Ti: 0.12 wt%, Si: 0.03 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the ratio, put them into a ball milling tank and fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd10 B 25 , the coating thickness is 15 μm; The composition of the intermediate high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , the coating thickness is 35 μm. Example 5: A steel for high-strength and high-corrosion-resistant photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has three-layer gradient coatings on the surface; The preparation method of the steel for high-strength and high-corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour them into a mold for molding; S3. Clean, sandblast and preheat the formed steel, perform plasma spraying and quickly cool it with compressed air until the three-layer gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and high-corrosion-resistant photovoltaic brackets; The composition of the steel matrix is composed of the following weight percentages: Mn: 1.29 wt%, Ni: 0.39 wt%, C: 0.20 wt%, Ti: 0.11 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.15 V 0.25 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the proportion, put them into a ball milling tank and fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, place it in a vacuum carbon tube furnace, evacuate the air, and heat it to conduct a carbothermal reduction reaction. The heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain a high-entropy carbide ceramic. S13. Put the high-entropy carbide ceramic into a ball milling tank, conduct ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm. The three-layer gradient coating is a high-entropy amorphous alloy coating. Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm. The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm. The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 6: A kind of steel for high-strength and high-corrosion-resistant photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface. The preparation method of the steel for high-strength and high-corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt. S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, then pour it into a mold for forming. S3. Clean, sandblast and preheat the formed steel, conduct plasma spraying and quickly cool it with compressed air until the three-layer gradient coating is sprayed. S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment. The heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and high-corrosion-resistant photovoltaic brackets. The composition of the steel matrix consists of the following weight percentages: Mn: 1.62 wt%, Ni: 0.27 wt%, C: 0.18 wt%, Ti: 0.15 wt%, Si: 0.04 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.25 V 0.15 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder in proportion, put them into a ball milling tank, fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, place it in a vacuum carbon tube furnace, evacuate the air, heat it to carry out a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, perform ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 7: A high-strength and highly corrosion-resistant steel for photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the high-strength and highly corrosion-resistant steel for photovoltaic brackets comprises the following steps: S1. Prepare each raw material required for the steel matrix in proportion, and heat it to 1580 °C to make the metal in a molten state, obtaining a metal melt; S2. Add high-entropy carbide ceramic nanoparticles into the metal melt, and mechanically stir until the particles are evenly distributed, then pour it into a mold for forming; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and rapidly cool it with compressed air until the three-layer gradient coating is sprayed; S4. Put the steel after spraying into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min, obtaining the high-strength and highly corrosion-resistant steel for photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.44 wt%, Ni: 0.37 wt%, C: 0.19 wt%, Ti: 0.10 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.15 Y 0.25 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles comprises the following steps: S11. Prepare each metal oxide powder and carbon powder in proportion, put them into a ball milling tank, fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10Gd 10 B 25 , the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , the coating thickness is 35 μm. Example 8: A steel for high-strength and highly corrosion-resistant photovoltaic brackets, which consists of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has three layers of gradient coatings on the surface; The preparation method of the steel for high-strength and highly corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare the raw materials required for the steel matrix according to the ratio, and heat to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour into a mold to form; S3. Clean, sandblast and preheat the formed steel, perform plasma spraying and use compressed air for rapid cooling until the three-layer gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and highly corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.59 wt%, Ni: 0.31 wt%, C: 0.17 wt%, Ti: 0.05 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.25 Y 0.15 )C, and the particle size is 200-500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder according to the ratio, put them into a ball milling tank, fill with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate, heat for carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramic into a ball milling jar, conduct ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 9: A high-strength and highly corrosion-resistant steel for photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the high-strength and highly corrosion-resistant steel for photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt and mechanically stir until the particles are evenly distributed, and pour it into a mold for molding; S3. Clean, sandblast and preheat the formed steel, conduct plasma spraying and use compressed air for rapid cooling until the three-layer gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the high-strength and highly corrosion-resistant steel for photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.28 wt%, Ni: 0.28 wt%, C: 0.20 wt%, Ti: 0.07 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb0.20 La 0.20 Y 0.20 ) C, the particle size of the particles is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles comprises the following steps: S11. Prepare the metal oxide powders and carbon powder in proportion, put them into a ball milling jar, fill with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate, heat for carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1850 °C, and then cool in the furnace to obtain a high-entropy carbide ceramic; S13. Put the high-entropy carbide ceramic into a ball milling jar, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 10: A high-strength and highly corrosion-resistant steel for photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the high-strength and highly corrosion-resistant steel for photovoltaic brackets comprises the following steps: S1. Prepare the raw materials required for the steel matrix in proportion, and heat to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour into a mold for molding; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and use compressed air for rapid cooling until the three-layer gradient coating is sprayed; S4. Put the steel with the sprayed coating into a heat treatment furnace for low-temperature relaxation treatment. The heat treatment temperature is 450 °C and the heat treatment time is 40 min to obtain the steel for high-strength and high-corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.55 wt%, Ni: 0.35 wt%, C: 0.18 wt%, Ti: 0.06 wt%, Si: 0.04 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder according to the ratio, put them into a ball milling tank, fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1900 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B25 , the coating thickness is 35 μm. Example 11: A steel for high-strength and highly corrosion-resistant photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has three-layer gradient coatings on the surface; The preparation method of the steel for high-strength and highly corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the ratio, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour it into a mold for molding; S3. Clean, sandblast and preheat the formed steel, perform plasma spraying and use compressed air for rapid cooling until the three-layer gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and highly corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.52 wt%, Ni: 0.31 wt%, C: 0.19 wt%, Ti: 0.14 wt%, Si: 0.01 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the ratio, put them into a ball milling tank, fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1950 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, perform ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coatings are high-entropy amorphous alloy coatings; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd10 B 25 , the coating thickness is 15 μm; The composition of the middle-layer high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , the coating thickness is 25 μm; The composition of the outer-layer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , the coating thickness is 35 μm. Example 12: A kind of steel for high-strength and high-corrosion-resistant photovoltaic brackets is composed of 96 wt% of steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and there are three-layer gradient coatings on the surface; The preparation method of the steel for high-strength and high-corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour it into a mold for forming; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and rapid cooling with compressed air until the three-layer gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and high-corrosion-resistant photovoltaic brackets; The composition of the steel matrix is composed of the following weight percentages: Mn: 1.41 wt%, Ni: 0.28 wt%, C: 0.22 wt%, Ti: 0.14 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the proportion, put them into a ball milling tank and fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, place it in a vacuum carbon tube furnace, evacuate the air, and heat it to conduct a carbothermal reduction reaction. The heating rate is 15 °C / min, the heating temperature is 2000 °C, and then cool it in the furnace to obtain a high-entropy carbide ceramic; S13. Put the high-entropy carbide ceramic into a ball milling jar, conduct ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Example 13: A kind of steel for high-strength and highly corrosion-resistant photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the steel for high-strength and highly corrosion-resistant photovoltaic brackets includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour it into a mold for forming; S3. Clean, sandblast and preheat the formed steel, conduct plasma spraying and quickly cool it with compressed air until the three-layer gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for high-strength and highly corrosion-resistant photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.42 wt%, Ni: 0.41 wt%, C: 0.15 wt%, Ti: 0.05 wt%, Si: 0.02 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder in proportion, put them into a ball milling tank, fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1900 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 10 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 20 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 30 μm. Example 14: A high-strength and highly corrosion-resistant steel for photovoltaic brackets is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the high-strength and highly corrosion-resistant steel for photovoltaic brackets comprises the following steps: S1. Prepare each raw material required for the steel matrix in proportion, and heat it to 1580 °C to make the metal in a molten state, obtaining a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, then pour it into a mold for molding; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and rapidly cool it with compressed air until the three-layer gradient coating is sprayed; S4. Put the steel after spraying into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min, obtaining the high-strength and highly corrosion-resistant steel for photovoltaic brackets; The composition of the steel matrix consists of the following weight percentages: Mn: 1.39 wt%, Ni: 0.29 wt%, C: 0.17 wt%, Ti: 0.13 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles comprises the following steps: S11. Prepare each metal oxide powder and carbon powder in proportion, put them into a ball milling tank, fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it to carry out a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1900 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 20 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10Gd 10 B 25 , the coating thickness is 30 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , the coating thickness is 40 μm. To further illustrate the technical effects of the present invention, the present invention also sets a comparative example, which is specifically as follows: Comparative Example 1: A steel for a photovoltaic support is composed of 90 wt% of a steel matrix and 10 wt% of high-entropy carbide ceramic nanoparticles, and there are three gradient coatings on the surface; The preparation method of the steel for the photovoltaic support includes the following steps: S1. Prepare the raw materials required for the steel matrix according to the ratio, and heat to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour into a mold for molding; S3. Clean, sandblast and preheat the formed steel, perform plasma spraying and use compressed air for rapid cooling until the three gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for the photovoltaic support; The composition of the steel matrix is composed of the following weight percentages: Mn: 1.46 wt%, Ni: 0.29 wt%, C: 0.19 wt%, Ti: 0.14 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder according to the ratio, put them into a ball milling tank and fill with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate, heat for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1800 °C, and then cool in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramic into a ball milling jar, conduct ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Comparative Example 2: A steel for a photovoltaic support is composed of 96 wt% of a steel matrix and 4 wt% of carbide ceramic nanoparticles, and has a three-layer gradient coating on the surface; The preparation method of the steel for the photovoltaic support includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add carbide ceramic nanoparticles to the metal melt and mechanically stir until the particles are evenly distributed, then pour it into a mold for molding; S3. Clean, sandblast and preheat the formed steel, conduct plasma spraying and use compressed air for rapid cooling until the three-layer gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for the photovoltaic support; The composition of the steel matrix consists of the following weight percentages: Mn: 1.33 wt%, Ni: 0.37 wt%, C: 0.18 wt%, Ti: 0.12 wt%, Si: 0.03 wt%, and the balance is Fe; The composition of the carbide ceramic nanoparticles is: (Ti 0.50 V 0.50 )C, and the particle size is 200 - 500 nm; The preparation method of the carbide ceramic nanoparticles comprises the following steps: S11. Prepare various metal oxide powders and carbon powder in proportion, put them into a ball milling tank, fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace, evacuate the air, heat it to perform a carbothermal reduction reaction, with a heating rate of 15 °C / min and a heating temperature of 1800 °C, and then cool it in the furnace to obtain carbide ceramics; S13. Put the carbide ceramics into a ball milling tank, perform ball milling and sieving to obtain carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Comparative Example 3: A steel for a photovoltaic support is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a three-layer gradient coating on its surface; The preparation method of the steel for a photovoltaic support comprises the following steps: S1. Prepare each raw material required for the steel matrix in proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour it into a mold to form; S3. Clean, sandblast and preheat the formed steel, perform plasma spraying and quickly cool it with compressed air until the three-layer gradient coating is sprayed completely; S4. Place the steel with spraying completed into a heat treatment furnace for low-temperature relaxation treatment. The heat treatment temperature is 450 °C and the heat treatment time is 40 min to obtain the steel for photovoltaic brackets. The composition of the steel matrix consists of the following weight percentages: Mn: 1.45 wt%, Ni: 0.43 wt%, C: 0.20 wt%, Ti: 0.10 wt%, Si: 0.03 wt%, and the balance is Fe. The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm. The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare the metal oxide powders and carbon powder according to the ratio, place them into a ball milling tank, fill with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder. S12. Load the uniformly mixed powder into a graphite mold, place it into a vacuum carbon tube furnace, evacuate, heat for carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1600 °C, and then cool in the furnace to obtain high-entropy carbide ceramics. S13. Place the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm. The three-layer gradient coating is a high-entropy amorphous alloy coating. Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm. The composition of the middle high-entropy amorphous alloy coating is Fe 20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 25 μm. The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 35 μm. Comparative Example 4: A steel for a photovoltaic support is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has three-layer gradient coatings on its surface; The preparation method of the steel for the photovoltaic support includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour it into a mold for forming; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and rapidly cool it with compressed air until the three-layer gradient coatings are sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for the photovoltaic support; The composition of the steel matrix consists of the following weight percentages: Mn: 1.52 wt%, Ni: 0.32 wt%, C: 0.17 wt%, Ti: 0.08 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the proportion, put them into a ball milling tank and fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 2200 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramics into a ball milling tank, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm; The three-layer gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 15 μm; The composition of the middle high-entropy amorphous alloy coating is Fe20 Cr 25 Ni 10 Mo 10 Gd 10 B 25 with a coating thickness of 25 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 with a coating thickness of 35 μm. Comparative Example 5: A steel for a photovoltaic support, consisting of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and having a gradient coating on the surface; The preparation method of the steel for a photovoltaic support includes the following steps: S1. Prepare each raw material required for the steel matrix according to the ratio, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour them into a mold for molding; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and use compressed air for rapid cooling until the gradient coating is sprayed; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain the steel for a photovoltaic support; The composition of the steel matrix consists of the following weight percentages: Mn: 1.29 wt%, Ni: 0.39 wt%, C: 0.16 wt%, Ti: 0.10 wt%, Si: 0.05 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200 - 500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare each metal oxide powder and carbon powder according to the ratio, put them into a ball milling tank and fill it with argon, and carry out high-energy ball milling to obtain a uniformly mixed powder; S12. Load the uniformly mixed powder into a graphite mold, put it into a vacuum carbon tube furnace and evacuate it, heat it for a carbothermal reduction reaction, the heating rate is 15 °C / min, the heating temperature is 1900 °C, and then cool it in the furnace to obtain high-entropy carbide ceramics; S13. Put the high-entropy carbide ceramic into a ball milling jar, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200-500 nm; The gradient coating is a high-entropy amorphous alloy coating; Among them, the composition of the inner high-entropy amorphous alloy coating is Fe 30 Cr 15 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 30 μm; The composition of the outer high-entropy amorphous alloy coating is Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 45 μm. Comparative Example 6: A steel for a photovoltaic support is composed of 96 wt% of a steel matrix and 4 wt% of high-entropy carbide ceramic nanoparticles, and has a coating on the surface; The preparation method of the steel for the photovoltaic support includes the following steps: S1. Prepare each raw material required for the steel matrix according to the proportion, and heat it to 1580 °C to make the metal in a molten state to obtain a metal melt; S2. Add high-entropy carbide ceramic nanoparticles to the metal melt, and mechanically stir until the particles are evenly distributed, and pour them into a mold for molding; S3. Clean, sandblast and preheat the formed steel, carry out plasma spraying and use compressed air for rapid cooling to complete the coating spraying; S4. Put the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment, the heat treatment temperature is 450 °C, and the heat treatment time is 40 min to obtain high-strength and highly corrosion-resistant steel for a photovoltaic support; The composition of the steel matrix is composed of the following weight percentages: Mn: 1.30 wt%, Ni: 0.41 wt%, C: 0.18 wt%, Ti: 0.06 wt%, Si: 0.03 wt%, and the balance is Fe; The composition of the high-entropy carbide ceramic nanoparticles is: (Ti 0.20 V 0.20 Nb 0.20 La 0.20 Y 0.20 )C, and the particle size is 200-500 nm; The preparation method of the high-entropy carbide ceramic nanoparticles includes the following steps: S11. Prepare metal oxide powders and carbon powder in proportion, put them into a ball milling jar, fill it with argon, and perform high-energy ball milling to obtain a uniformly mixed powder. S12. Load the uniformly mixed powder into a graphite mold, place it in a vacuum carbon tube furnace, evacuate the air, heat it to carry out a carbothermal reduction reaction. The heating rate is 15 °C / min, the heating temperature is 1900 °C, and then cool it in the furnace to obtain a high-entropy carbide ceramic. S13. Put the high-entropy carbide ceramic into a ball milling jar, carry out ball milling and sieving to obtain high-entropy carbide ceramic nanoparticles with a particle size of 200 - 500 nm. The coating is a high-entropy amorphous alloy coating, and its components are Fe 10 Cr 35 Ni 10 Mo 10 Gd 10 B 25 , and the coating thickness is 75 μm. Use a universal testing machine to test the tensile properties of the uncoated sample, and measure the corrosion rate of the coated sample through an electrochemical polarization curve. The electrolyte is a 3.5 wt% NaCl aqueous solution, and the results are shown in Tables 1 - 4. Table 1 Influence of different reinforcing phase contents on the properties of steel Table 2 Influence of different reinforcing phase components on the properties of steel Table 3 Influence of different high-entropy carbide sintering temperatures on the properties of steel Table 4 Influence of different coating thicknesses on the properties of steel In summary, the present invention has a high yield strength and tensile strength, excellent mechanical properties. Compared with the comparative example, the gradient coating has stronger corrosion resistance than the single coating, and the comprehensive performance is excellent, having good application prospects in the field of photovoltaic support materials. The above embodiments are only used to illustrate the present invention and do not constitute a limitation. Without departing from the technical concept involved in the present invention, several variations and improvements made by those skilled in the art all fall within the protection scope of the present invention.

Claims

1. A high-strength and high-corrosion-resistant steel for photovoltaic brackets, characterized in that: The photovoltaic support steel consists of 95-98wt% of a steel matrix and 2-5wt% of high-entropy carbide ceramic nanoparticles, and has three layers of gradient coating on the surface.

2. The method for preparing high-strength and high-corrosion-resistant photovoltaic support steel according to claim 1, characterized in that: The following steps are involved: S1. The raw materials required for the steel matrix are prepared in proportion and heated to a molten state to obtain a molten metal; S2. adding high entropy carbide ceramic nanoparticles to the metal melt, mechanically stirring until the particles are evenly distributed, and pouring into a mold for molding; S3. The formed steel is cleaned, sandblasted and preheated, plasma sprayed and rapidly cooled with compressed air until the three-layer gradient coating is sprayed; S4. Place the sprayed steel into a heat treatment furnace for low-temperature relaxation treatment to obtain high-strength and high-corrosion-resistant steel for photovoltaic brackets.

3. The method for preparing high-strength and high-corrosion-resistant photovoltaic support steel according to claim 2, characterized in that: The heating temperature in step S1 is 1570-1590°C.

4. The method for preparing high-strength and high-corrosion-resistant photovoltaic support steel according to claim 2, characterized in that: The heat treatment temperature in step S4 is 440-460° C., and the heat treatment time is 20-60 min.

5. The high-strength and high-corrosion-resistant photovoltaic support steel according to claim 1 is characterized in that: The steel matrix is ​​composed of the following weight percentages: Mn: 1.25-1.65wt%, Ni: 0.25-0.45wt%, C: 0.15-0.22wt%, Ti: 0.05-0.15wt%, Si: ≤0.05wt%, and the balance is Fe.

6. The high-strength and high-corrosion-resistant photovoltaic support steel according to claim 1 is characterized in that: The composition of the high entropy carbide ceramic nanoparticles is: (Ti 0.15-0.25 V 0.15-0.25 Nb 0.15-0.25 La 0.15-0.25 Y 0.15-0.25 )C, the particle size is 200~500nm.

7. The high-strength and high-corrosion-resistant photovoltaic support steel according to claim 1 is characterized in that: The method for preparing the high entropy carbide ceramic nanoparticles comprises the following steps: S11. The metal oxide powders and carbon powders were prepared in proportion, placed in a ball mill and filled with argon gas, and subjected to high-energy ball milling to obtain a uniformly mixed powder; S12. The mixed powder is loaded into a graphite mold, placed in a vacuum carbon tube furnace and evacuated, heated for carbon thermal reduction reaction and cooled to obtain a high entropy carbide ceramic; S13. The high entropy carbide ceramic is placed in a ball mill, ball-milled and crushed, and sieved to obtain high entropy carbide ceramic nanoparticles with a particle size of 200 to 500 nm.

8. The high-strength and high-corrosion-resistant photovoltaic support steel according to claim 7 is characterized in that: The heating rate in step S12 is 10-20°C / min, and the heating temperature is 1800-2000°C.

9. The high-strength and high-corrosion-resistant photovoltaic support steel according to claim 1, characterized in that: The three-layer gradient coating is a high entropy amorphous alloy coating; The composition of the inner high entropy amorphous alloy coating is Fe 30-35 Cr 10-15 Ni 5-15 Mo 5-15 G 5-15 B 20-30 , coating thickness is 10-20 μm; The composition of the intermediate layer high entropy amorphous alloy coating is Fe 20-25 Cr 20-25 Ni 5-15 Mo 5-15 G 5-15 B 20-30 , coating thickness is 20-30μm; The composition of the outer high entropy amorphous alloy coating is Fe 10-15 Cr 30-35 Ni 5-15 Mo 5-15 G 5-15 B 20-30 , the coating thickness is 30~40μm.

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