Multi-element composite micro-alloyed iron-based material for iron pan and preparation method of multi-element composite micro-alloyed iron-based material

Abstract

The invention relates to the technical field of composite materials, and discloses a multi-element composite micro-alloyed iron-based material for an iron pan and a preparation method of the multi-element composite micro-alloyed iron-based material. Comprising the following operation steps that the microalloyed iron-based material is subjected to acid pickling and then subjected to nitrogen drying, Fe-Al alloy powder is firstly subjected to laser cladding on the surface of the microalloyed iron-based material to form a transition layer, then high-thermal-conductivity Al-Mg-Zn-Si premixed powder is subjected to cladding, a high-thermal-conductivity alloy layer is formed, solid solution is conducted, and a microalloyed iron-based material A is obtained; and 2, the micro-alloyed iron-based material A is placed in the electrolyte for micro-arc oxidation, a micro-arc oxidation layer is formed, and the multi-element composite micro-alloyed iron-based material is obtained.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a multi-component composite microalloyed iron-based material for iron pots and its preparation method. Background Technology

[0002] Traditional iron pots, as cooking utensils, have obvious limitations in their material properties; ordinary iron-based materials have a low thermal conductivity, which leads to uneven heat distribution during cooking, easily causing local overheating and affecting the quality of the dishes; in addition, the surface of iron pots is not very hard and is prone to wear and tear with long-term use, and the traditional iron surface is prone to oxidation and corrosion, making maintenance inconvenient.

[0003] To improve performance, cookware made of materials such as stainless steel, aluminum, or copper has appeared on the market. Stainless steel cookware is corrosion resistant but has poor thermal conductivity. Aluminum and copper cookware have good thermal conductivity, but aluminum has insufficient strength and copper is expensive. Existing surface treatment technologies such as Teflon coating have low hardness and are easy to peel off, posing health risks. Although stainless steel composite cookware has improved corrosion resistance, it is difficult to balance thermal conductivity and hardness, thus affecting performance.

[0004] In summary, to solve the above problems, a multi-component composite microalloyed iron-based material for iron pots is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-component composite microalloyed iron-based material for iron pots and its preparation method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a multi-component composite microalloyed iron-based material for iron pots includes the following steps: Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder are mixed at a mass ratio of (6~9):1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) After acid washing, microalloyed iron-based material is dried with nitrogen gas, and Fe-Al alloy powder is first laser-coated on its surface to form a transition layer, and then high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer. After solid solution treatment, microalloyed iron-based material A is obtained. Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer, thus obtaining a multi-component composite microalloyed iron-based material.

[0007] In a more optimized form, the raw materials of the microalloyed iron-based material include the following components, by percentage: 0.02~0.04wt%C, 0.06~0.075wt%Nb, 1.6~2wt%Mn, 5.5~5.8wt%Al, with the remainder being iron; the raw materials of the Al-Mg-Zn-Si pre-alloyed powder include the following components, by percentage: 93~96wt%Al, 2~4wt%Si, 0.6~1wt%Mg, 1.4~2wt%Zn; the raw materials of the Fe-Al alloy powder include the following components, by percentage: 70~75wt%Fe, 25~30wt%Al.

[0008] More optimized, the Fe-Al alloy powder has a particle size of 50~150μm; the Al-Mg-Zn-Si pre-alloy powder has a particle size of 50~150µm; and the h-BN / Al2Cu / Cu composite powder has a particle size of 400~600nm.

[0009] In a more optimized configuration, the thickness of the transition layer is 0.4~0.5 mm; the thickness of the high thermal conductivity alloy layer is 0.6~0.8 mm; and the thickness of the micro-arc oxidation layer is 5~10 μm.

[0010] Both the Fe-Al alloy powder and the Al-Mg-Zn-Si pre-alloy powder were prepared using the conventional gas atomization method in this field.

[0011] A more optimized method for preparing the h-BN / Al2Cu / Cu composite powder is as follows: (1) h-BN-OH and Cu2(OH)3NH3 are added to ethanol and mixed, propylene oxide is added and ultrasonically sonicated until a sol is formed; PEG is added to ethanol and stirred evenly, activated aluminum powder is added and mixed, added to the sol and mixed, aged for 3-5 days, dried, calcined at 350-400℃ for 4-5 hours, and ground to obtain h-BN / Al2Cu composite powder; (2) h-BN / Al2Cu composite powder and CuCl2·H2O are added to ethylene glycol and mixed, hydrazine hydrate is added, kept at 140-150℃ for 10-15 hours, washed and dried to obtain h-BN / Al2Cu / Cu composite powder.

[0012] In a more optimized form, the raw materials of the h-BN / Al2Cu composite powder include the following components: by mass parts, 2-3 parts h-BN-OH, 2-4 parts Cu2(OH)3NH3, 30-50 parts ethanol, 1.5-3 parts propylene oxide, 0.2-0.4 parts PEG, and 0.5-0.8 parts activated aluminum powder; The raw materials of the h-BN / Al2Cu / Cu composite powder include the following components: by mass, 3-5 parts h-BN / Al2Cu composite powder, 1-2 parts CuCl2·H2O, 40-50 parts ethylene glycol, and 10-20 parts hydrazine hydrate.

[0013] The preparation method of activated aluminum powder is as follows: aluminum powder is added to a 0.1~0.2M sulfuric acid mixture and treated at room temperature for 20~30 minutes, then washed and dried with nitrogen to obtain activated aluminum powder.

[0014] The preparation method of h-BN-OH is as follows: boron nitride (6-10 layers of boron nitride with a particle size of 150-300 nm) is added to a 3-5 mol / L NaOH solution and stirred for 30-40 minutes. The solution is then refluxed at 110-120℃ for 5-8 hours, cooled to room temperature, washed until neutral, and dried to obtain h-BN-OH. The risk of damaging the boron nitride structure is reduced by controlling the temperature and reflux time.

[0015] In this scheme, the hydroxyl groups on the surface of h-BN-OH are active sites, which interact with Cu2(OH)3NH3 in the ethanol medium and disperse uniformly; Cu2(OH)3NH3 dissociates in ethanol to form Cu 2+ After adding a propylene oxide hydrolysis inducer, the epoxy groups of propylene oxide undergo ring-opening, promoting Cu... 2+ It reacts with OH- and NH3 in the system to form a stable sol containing boron nitride; polyethylene glycol (PEG) improves the dispersibility of activated aluminum powder. Upon calcination at high temperature, Cu2(OH)3NH3 decomposes into CuO, which undergoes an aluminothermic reaction with Al, displacing elemental Cu, and then forms an Al-Cu alloy (Al2Cu) with Al, forming h-BN / Al2Cu; the strong reducing properties of hydrazine hydrate and the alkaline environment ensure the stability of Cu. 2+ Directional reduction to elemental Cu; under solvothermal conditions, Cu atoms are deposited in situ on the surface of h-BN / Al2Cu, forming a uniform h-BN / Al2Cu / Cu composite powder structure.

[0016] In a more optimized form, the electrolyte raw materials include the following components: 14~18 g / L sodium hexametaphosphate, 5~9 g / L sodium phosphate, 4~6 g / L ammonium acetate, and 3~5 g / L modified h-BN / Al2Cu composite powder.

[0017] A more optimized method for preparing the modified h-BN / Al2Cu composite powder is as follows: h-BN / Al2Cu composite powder is added to an oxalic acid aqueous solution for 12-20 seconds, removed and washed, added to a phosphating solution for treatment, removed and washed, added to a sodium aluminate solution for 10-20 minutes, removed, washed and dried to obtain the modified h-BN / Al2Cu composite powder.

[0018] More preferably, the concentration of the oxalic acid aqueous solution is 2-3 wt%; the raw materials of the phosphating solution include the following components: 18-20 g / L zinc dihydrogen phosphate, 5-7 g / L zinc nitrate, and 1.5-3 g / L phytic acid; the concentration of the sodium aluminate solution is 10-20 wt%.

[0019] In the proposed scheme, the chemical structures of h-BN and the micro-arc oxidation layer are very different, resulting in weak bonding. h-BN itself is difficult to phosphate, but after Al2Cu deposition, it is activated by oxalic acid and then treated in a phosphate solution to form a phosphate film. Now, the surface of the phosphated h-BN / Al2Cu composite powder is pre-coated with an aluminum oxide layer, which is similar in composition and structure to the subsequent ceramic matrix, promoting the interfacial compatibility between the two during the micro-arc oxidation process.

[0020] Compared with the prior art, the beneficial effects of the present invention are: In this scheme, a lightweight, low-carbon Fe-Al-Mn-Nb microalloying system is selected. Low carbon ensures the thermal conductivity of the iron-based matrix; low C ensures the thermal conductivity foundation; Nb refines the grains to improve high-temperature stability; Mn improves the compatibility of the cladding interface; and Al synergistically enhances thermal conductivity and oxidation resistance, providing a good metallurgical bonding substrate for the subsequent cladding layer. With Al as the thermally conductive matrix, Si, h-BN / Cu, Mg, and Zn are composited to construct an efficient thermally conductive channel. Furthermore, Si improves cladding fluidity, h-BN / Cu synergistically enhances thermal conductivity and wear resistance, Mg deoxidizes and prevents oxidation, and Zn optimizes the forming quality. Lightweight, low-carbon Fe-Al-Mn-Nb microalloying bottom laser cladding: First, laser cladding Fe-Al alloy powder as a transition layer between the substrate and the upper coating improves the diffusion and bonding between the substrate and the upper coating, solves the problem of mismatch in thermal expansion coefficients between the iron substrate and Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder, and reduces thermal stress cracks during the cladding process; In this design, a few layers of h-BN are chosen because its vertical hot surface has low thermal resistance, resulting in high thermal conductivity. Combining it with Cu can effectively improve thermal conductivity, but the two are essentially thermodynamically incompatible systems. Even if h-BN / Cu is formed to improve thermal conductivity, Cu atoms easily diffuse at the high temperatures of laser cladding, leading to voids at the h-BN-Cu interface, thus weakening the interfacial bonding and affecting thermal conductivity. To address this issue, Al2Cu is placed at the h-BN-Cu interface as a rigid transition layer, hindering excessive diffusion of Cu atoms and suppressing the high-temperature migration of h-BN. During laser cladding, Al2Cu partially decomposes, while h-BN is better dispersed in the alloy, fully utilizing its thermal conductivity potential instead of agglomerating or being repelled, thereby balancing the overall thermal conductivity of the material and improving wear resistance.

[0021] In this scheme, to improve the mechanical properties of the multi-component composite micro-alloyed iron-based material, a micro-arc oxidation layer is set on its surface to enhance wear resistance and strength. However, the micro-arc oxidation layer has poor thermal conductivity. To mitigate the impact of the micro-arc oxidation layer on the overall thermal conductivity, ammonium salt is added to the micro-arc oxidation electrolyte. This promotes the formation of aluminum nitride and also has a certain dispersing effect on the modified h-BN / Al2Cu composite powder. h-BN has good insulation properties, but poor interfacial compatibility with the micro-arc oxidation layer. Al2Cu has certain conductivity, which can reduce the fluctuations in electrolyte conductivity caused by the insulation of h-BN, avoid uneven micro-arc discharge, and prevent local defects in the thermal conductivity of the thermal conductive layer, thus balancing the overall thermal conductivity. In this scheme, the modified h-BN / Al2Cu composite powder reacts with the phosphate electrolyte to form chemical bonds, improving the bonding force with the oxide film and preventing it from falling off during use. This not only does not affect the thermal conductivity but also enhances the stability of the oxide layer. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] In the following specific embodiments, the parts are by weight. In this embodiment, it should be noted that there are no special restrictions on the purchase manufacturers of all the raw materials involved in this invention. Exemplary examples include: propylene oxide CAS number 75-56-9; PEG (polyethylene glycol) 2000; CuCl2·H2O (copper chloride dihydrate) CAS number 10125-13-0; hydrazine hydrate CAS number 7803-57-8; sodium hexametaphosphate CAS number 10124-56-8; ammonium acetate CAS number 631-61-8; sodium phosphate CAS number 7632-05-5.

[0024] The raw materials for the phosphating solution include the following components: 18 g / L zinc dihydrogen phosphate, 7 g / L zinc nitrate, and 1.5 g / L phytic acid.

[0025] Example 1: A method for preparing a multi-component composite microalloyed iron-based material for iron pots, comprising the following steps: Pre-preparation: The preparation method of h-BN / Al2Cu / Cu composite powder is as follows: (1) 2.7 parts of h-BN-OH and 2 parts of Cu2(OH)3NH3 are added to 40 parts of ethanol and mixed. 1.8 parts of propylene oxide are added and ultrasonically sonicated until sol is generated. 0.3 parts of PEG2000 are added to ethanol and stirred evenly. 0.5 parts of activated aluminum powder are added and mixed. The mixture is added to the sol and mixed. The mixture is aged for 5 days, dried, calcined at 350℃ for 5 hours, and ground to obtain h-BN / Al2Cu composite powder. (2) 3 parts of h-BN / Al2Cu composite powder and 1.5 parts of CuCl2·H2O are added to 40 parts of ethylene glycol and mixed. 10 parts of hydrazine hydrate are added and kept at 140℃ for 12 hours. The mixture is washed and dried to obtain h-BN / Al2Cu / Cu composite powder. The preparation method of modified h-BN / Al2Cu composite powder is as follows: h-BN / Al2Cu composite powder is added to 3wt% oxalic acid aqueous solution and ultrasonically treated for 15 seconds, taken out and cleaned, added to phosphating solution and treated at 70℃ for 15 minutes, taken out and cooled, cleaned, added to sodium aluminate solution (concentration of 15wt%) for 20 minutes, taken out, cleaned and dried to obtain modified h-BN / Al2Cu composite powder; The electrolyte raw materials include the following components: 16 g / L sodium hexametaphosphate, 8 g / L sodium phosphate, 4.5 g / L ammonium acetate, and 3 g / L modified h-BN / Al2Cu composite powder; Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder (123µm) and h-BN / Al2Cu / Cu composite powder (523nm) are mixed at a mass ratio of 6:1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) After acid washing, microalloyed iron-based material is dried with nitrogen gas. First, Fe-Al alloy powder (131µm) is laser-coated on its surface to form a transition layer with a thickness of 0.42mm. Then, high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer with a thickness of 0.65mm. The material is kept at 480℃ for 2 hours to obtain microalloyed iron-based material A; The laser cladding process conditions for the transition layer are: nitrogen protection, power 1800W, scanning rate 4mm / s, and powder feed rate 22g / min; the laser cladding process conditions for the high thermal conductivity alloy layer are: nitrogen protection, power 1400W, scanning rate 6mm / s, and powder feed rate 20g / min. Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 5.2 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for the microalloyed iron-based material include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; the raw materials for the Al-Mg-Zn-Si pre-alloyed powder include the following components, by percentage: 93wt% Al, 4wt% Si, 1wt% Mg, 2wt% Zn; the raw materials for the Fe-Al alloy powder include the following components, by percentage: 72wt% Fe, 28wt% Al; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0026] Example 2: A method for preparing a multi-component composite microalloyed iron-based material for iron pots, comprising the following steps: Pre-preparation: The preparation method of h-BN / Al2Cu / Cu composite powder is as follows: (1) 2.7 parts of h-BN-OH and 2 parts of Cu2(OH)3NH3 are added to 40 parts of ethanol and mixed. 1.8 parts of propylene oxide are added and ultrasonically sonicated until sol is generated. 0.3 parts of PEG2000 are added to ethanol and stirred evenly. 0.5 parts of activated aluminum powder are added and mixed. The mixture is added to the sol and mixed. The mixture is aged for 5 days, dried, calcined at 350℃ for 5 hours, and ground to obtain h-BN / Al2Cu composite powder. (2) 3 parts of h-BN / Al2Cu composite powder and 1.5 parts of CuCl2·H2O are added to 40 parts of ethylene glycol and mixed. 10 parts of hydrazine hydrate are added and kept at 140℃ for 12 hours. The mixture is washed and dried to obtain h-BN / Al2Cu / Cu composite powder. The preparation method of modified h-BN / Al2Cu composite powder is as follows: h-BN / Al2Cu composite powder is added to 3wt% oxalic acid aqueous solution and ultrasonically treated for 15 seconds, taken out and cleaned, added to phosphating solution and treated at 70℃ for 15 minutes, taken out and cooled, cleaned, added to sodium aluminate solution (concentration of 15wt%) for 20 minutes, taken out, cleaned and dried to obtain modified h-BN / Al2Cu composite powder; The electrolyte raw materials include the following components: 16 g / L sodium hexametaphosphate, 8 g / L sodium phosphate, 4.5 g / L ammonium acetate, and 3 g / L modified h-BN / Al2Cu composite powder; Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder are mixed at a mass ratio of 6:1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) Microalloyed iron-based material is acid-washed and dried with nitrogen. Fe-Al alloy powder is first laser-coated on its surface to form a transition layer with a thickness of 0.42 mm. Then, high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer with a thickness of 0.7 mm. The material is kept at 480℃ for 2 hours to obtain microalloyed iron-based material A; The laser cladding process conditions for the transition layer are: nitrogen protection, power 1800W, scanning rate 4mm / s, and powder feed rate 22g / min; the laser cladding process conditions for the high thermal conductivity alloy layer are: nitrogen protection, power 1400W, scanning rate 6mm / s, and powder feed rate 20g / min. Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 7.4 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for the microalloyed iron-based material include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; the raw materials for the Al-Mg-Zn-Si pre-alloyed powder include the following components, by percentage: 93wt% Al, 4wt% Si, 1wt% Mg, 2wt% Zn; the raw materials for the Fe-Al alloy powder include the following components, by percentage: 72wt% Fe, 28wt% Al; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0027] Example 3: A method for preparing a multi-component composite microalloyed iron-based material for iron pots, comprising the following steps: Pre-preparation: The preparation method of h-BN / Al2Cu / Cu composite powder is as follows: (1) 2.7 parts of h-BN-OH and 2 parts of Cu2(OH)3NH3 are added to 40 parts of ethanol and mixed. 1.8 parts of propylene oxide are added and ultrasonically sonicated until sol is generated. 0.3 parts of PEG2000 are added to ethanol and stirred evenly. 0.5 parts of activated aluminum powder are added and mixed. The mixture is added to the sol and mixed. The mixture is aged for 5 days, dried, calcined at 350℃ for 5 hours, and ground to obtain h-BN / Al2Cu composite powder. (2) 3 parts of h-BN / Al2Cu composite powder and 1.5 parts of CuCl2·H2O are added to 40 parts of ethylene glycol and mixed. 10 parts of hydrazine hydrate are added and kept at 140℃ for 12 hours. The mixture is washed and dried to obtain h-BN / Al2Cu / Cu composite powder. The preparation method of modified h-BN / Al2Cu composite powder is as follows: h-BN / Al2Cu composite powder is added to 3wt% oxalic acid aqueous solution and ultrasonically treated for 15 seconds, taken out and cleaned, added to phosphating solution and treated at 70℃ for 15 minutes, taken out and cooled, cleaned, added to sodium aluminate solution (concentration of 15wt%) for 20 minutes, taken out, cleaned and dried to obtain modified h-BN / Al2Cu composite powder; The electrolyte raw materials include the following components: 16 g / L sodium hexametaphosphate, 8 g / L sodium phosphate, 4.5 g / L ammonium acetate, and 3 g / L modified h-BN / Al2Cu composite powder; Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder are mixed at a mass ratio of 6:1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) After acid washing, microalloyed iron-based material is dried with nitrogen. First, Fe-Al alloy powder is laser-coated on its surface to form a transition layer with a thickness of 0.42 mm. Then, high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer with a thickness of 0.8 mm. The material is kept at 480℃ for 2 hours to obtain microalloyed iron-based material A; The laser cladding process conditions for the transition layer are: nitrogen protection, power 1800W, scanning rate 4mm / s, and powder feed rate 22g / min; the laser cladding process conditions for the high thermal conductivity alloy layer are: nitrogen protection, power 1400W, scanning rate 6mm / s, and powder feed rate 20g / min. Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 9.6 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for the microalloyed iron-based material include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; the raw materials for the Al-Mg-Zn-Si pre-alloyed powder include the following components, by percentage: 93wt% Al, 4wt% Si, 1wt% Mg, 2wt% Zn; the raw materials for the Fe-Al alloy powder include the following components, by percentage: 72wt% Fe, 28wt% Al; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0028] Comparative Example 1 is based on Example 3, but uses a silicate electrolyte; the remaining steps are the same. Pre-preparation: The raw materials for the electrolyte include the following components: 20 g / L sodium silicate, 5 g / L sodium hydroxide, 4.5 g / L ammonium acetate, and 3 g / L modified h-BN / Al2Cu composite powder; Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder are mixed at a mass ratio of 6:1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) After acid washing, microalloyed iron-based material is dried with nitrogen. First, Fe-Al alloy powder is laser-coated on its surface to form a transition layer with a thickness of 0.42 mm. Then, high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer with a thickness of 0.8 mm. The material is kept at 480℃ for 2 hours to obtain microalloyed iron-based material A; Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 9.6 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for microalloyed iron-based materials include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0029] Comparative Example 2 is based on Example 3, except that the h-BN / Al2Cu / Cu composite powder is replaced with h-BN / Cu composite powder; the remaining operating steps are the same. Pre-preparation: The preparation method of h-BN / Cu composite powder is as follows: 3 parts of h-BN-OH composite powder and 1.5 parts of CuCl2·H2O are added to 40 parts of ethylene glycol and mixed. 10 parts of hydrazine hydrate are added and kept at 140℃ for 12 hours. After washing and drying, h-BN / Cu composite powder is obtained. Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu composite powder are mixed at a mass ratio of 6:1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) Microalloyed iron-based material is acid-washed and dried with nitrogen. Fe-Al alloy powder is first laser-coated on its surface to form a transition layer with a thickness of 0.42 mm. Then, high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer with a thickness of 0.8 mm. The material is kept at 480℃ for 2 hours to obtain microalloyed iron-based material A; Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 9.6 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for microalloyed iron-based materials include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0030] Comparative Example 3 is based on Example 3, using direct micro-arc oxidation; the remaining operation steps are the same. Step 1: Place the microalloyed iron-based material in an electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 9.6 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for microalloyed iron-based materials include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0031] Comparative Example 4 is based on Example 3, but without the addition of modified h-BN / Al2Cu composite powder to the electrolyte; the remaining operating steps are the same. Pre-preparation: The raw materials for the electrolyte include the following components: 16 g / L sodium hexametaphosphate, 8 g / L sodium phosphate, and 4.5 g / L ammonium acetate; Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder are mixed at a mass ratio of 6:1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) After acid washing, microalloyed iron-based material is dried with nitrogen. First, Fe-Al alloy powder is laser-coated on its surface to form a transition layer with a thickness of 0.42 mm. Then, high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer with a thickness of 0.8 mm. The material is kept at 480℃ for 2 hours to obtain microalloyed iron-based material A; Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer with a thickness of 9.6 μm, thus obtaining a multi-component composite microalloyed iron-based material; The raw materials for microalloyed iron-based materials include the following components: 0.03wt% C, 0.072wt% Nb, 1.8wt% Mn, 5.5wt% Al, with the remainder being iron; During the micro-arc oxidation process, the power supply mode is selected as a bipolar pulse voltage mode with positive and negative constant voltage. The positive termination voltage is 590V, the positive-to-negative stage ratio is 1:1, the negative pulse frequency is 800Hz, and the duty cycle is 10%.

[0032] Testing: The thermal conductivity (W·m) of Examples 1-3 and Comparative Examples 1-4 was tested at temperatures ranging from 27℃ to 200℃.-1 ·K -1 ) and hardness (HV); Table 1 Conclusions: Comparative Example 1, based on Example 2, used a silicate electrolyte; during micro-arc oxidation, a low thermal conductivity mullite phase was generated, which disrupted the thermal conductivity pathway of aluminum nitride, resulting in reduced thermal conductivity but increased hardness; Comparative Example 2, based on Example 2, replaced h-BN / Al2Cu / Cu composite powder with h-BN / Cu composite powder; h-BN / Cu composite powder lacks an Al2Cu transition layer, leading to a decrease in the interfacial bonding between h-BN and the metal material during high-temperature cladding, thus affecting the material's performance; Comparative Example 3, based on Example 2, involved direct micro-arc oxidation, resulting in a significant reduction in material performance; Comparative Example 4, based on Example 2, did not add modified h-BN / Al2Cu composite powder to the electrolyte; the lack of modified h-BN / Al2Cu composite powder resulted in reduced performance.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a multi-component composite microalloyed iron-based material for iron pots, characterized in that: The following steps are included: Step 1: (1) Al-Mg-Zn-Si pre-alloyed powder and h-BN / Al2Cu / Cu composite powder are mixed at a mass ratio of (6~9):1 to obtain high thermal conductivity Al-Mg-Zn-Si premixed powder; (2) After acid washing, microalloyed iron-based material is dried with nitrogen gas, and Fe-Al alloy powder is first laser-coated on its surface to form a transition layer, and then high thermal conductivity Al-Mg-Zn-Si premixed powder is coated to form a high thermal conductivity alloy layer. After solid solution treatment, microalloyed iron-based material A is obtained. Step 2: Place the microalloyed iron-based material A in the electrolyte for micro-arc oxidation to form a micro-arc oxidation layer, thus obtaining a multi-component composite microalloyed iron-based material.

2. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 1, characterized in that: The raw materials for the microalloyed iron-based material include the following components, by percentage: 0.02~0.04wt%C, 0.06~0.075wt%Nb, 1.6~2wt%Mn, 5.5~5.8wt%Al, with the remainder being iron; the raw materials for the Al-Mg-Zn-Si pre-alloyed powder include the following components, by percentage: 93~96wt%Al, 2~4wt%Si, 0.6~1wt%Mg, 1.4~2wt%Zn; the raw materials for the Fe-Al alloy powder include the following components, by percentage: 70~75wt%Fe, 25~30wt%Al.

3. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 1, characterized in that: The Fe-Al alloy powder has a particle size of 50~150μm; the Al-Mg-Zn-Si pre-alloy powder has a particle size of 50~150µm; and the h-BN / Al2Cu / Cu composite powder has a particle size of 400~600nm.

4. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 1, characterized in that: The thickness of the transition layer is 0.4~0.5mm; the thickness of the high thermal conductivity alloy layer is 0.5~0.8mm; and the thickness of the micro-arc oxidation layer is 5~10μm.

5. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 1, characterized in that: The preparation method of the h-BN / Al2Cu / Cu composite powder is as follows: (1) h-BN-OH and Cu2(OH)3NH3 are added to ethanol and mixed, propylene oxide is added and ultrasonically sonicated until sol is generated; PEG is added to ethanol and stirred evenly, activated aluminum powder is added and mixed, added to sol and mixed, aged for 3~5 days, dried, calcined at 350~400℃ for 4~5 hours, ground, and h-BN / Al2Cu composite powder is obtained; (2) h-BN / Al2Cu composite powder and CuCl2·H2O are added to ethylene glycol and mixed, hydrazine hydrate is added, kept at 140~150℃ for 10~15 hours, washed and dried, and h-BN / Al2Cu / Cu composite powder is obtained.

6. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 5, characterized in that: The raw materials of the h-BN / Al2Cu composite powder include the following components by mass: 2-3 parts h-BN-OH, 2-4 parts Cu2(OH)3NH3, 30-50 parts ethanol, 1.5-3 parts propylene oxide, 0.2-0.4 parts PEG, and 0.5-0.8 parts activated aluminum powder; The raw materials of the h-BN / Al2Cu / Cu composite powder include the following components: by mass, 3-5 parts h-BN / Al2Cu composite powder, 1-2 parts CuCl2·H2O, 40-50 parts ethylene glycol, and 10-20 parts hydrazine hydrate.

7. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 1, characterized in that: The electrolyte raw materials include the following components: 14~18g / L sodium hexametaphosphate, 5~9g / L sodium phosphate, 4~6g / L ammonium acetate, and 3~5g / L modified h-BN / Al2Cu composite powder.

8. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 7, characterized in that: The modified h-BN / Al2Cu composite powder is prepared by adding h-BN / Al2Cu composite powder into an oxalic acid aqueous solution for 12-20 seconds, removing and washing, adding it into a phosphating solution for treatment, removing and washing, adding it into a sodium aluminate solution for 10-20 minutes, removing, washing and drying to obtain the modified h-BN / Al2Cu composite powder.

9. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to claim 8, characterized in that: The concentration of the oxalic acid aqueous solution is 2-3 wt%; the raw materials of the phosphating solution include the following components: 18-20 g / L zinc dihydrogen phosphate, 5-7 g / L zinc nitrate, and 1.5-3 g / L phytic acid; the concentration of the sodium aluminate solution is 10-20 wt%.

10. The method for preparing a multi-component composite microalloyed iron-based material for iron pots according to any one of claims 1 to 9 yields a multi-component composite microalloyed iron-based material.

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