High-wear-resistance wire-drawing die coating and preparation process thereof

Abstract

The invention relates to the technical field of mold coatings, and discloses a high-wear-resistance wire-drawing mold coating and a preparation process thereof. Comprising the following operation steps that 1, porous ceramic powder and nickel-based self-fluxing alloy powder are mixed, and transition layer powder is obtained; (2) carrying out laser cladding on the surface of the pretreated wire-drawing die with transition layer powder to form a transition layer so as to obtain a wire-drawing die A; 2, the surface of a wire drawing die A is coated with Al2O3-Mo-based nano-composite sol, a wear-resistant coating is formed through curing, and a high-wear-resistant wire drawing die coating is obtained; the porous ceramic powder is used as a transition layer, the Al2O3-Mo-based nano composite sol permeates into the porous ceramic powder, and after curing treatment, the interface bonding force between the sol and the wire drawing die is improved, so that the wear resistance of the wire drawing die is enhanced.

Description

Technical Field

[0001] This invention relates to the field of mold coating technology, specifically a high wear-resistant wire drawing mold coating and its preparation process. Background Technology

[0002] Wire drawing dies are the core components of metal wire processing. During the drawing process of difficult-to-process wires such as stainless steel and high-strength alloys, the inner wall of the die is subjected to severe friction, extrusion and thermal stress, which leads to frequent die replacements and increases production costs.

[0003] Existing wire drawing die coatings mainly include diamond-like carbon (DLC) films, hard coatings such as TiN and CrN, and Al2O3 ceramic coatings. Although DLC films have high hardness, they have poor high-temperature stability and are prone to oxidation and failure during the drawing process. TiN and CrN coatings have insufficient wear resistance and are difficult to adapt to high-strength wire processing. Al2O3 ceramic coatings have good high-temperature stability, but the interfacial bonding strength with the wire drawing die affects the wear resistance of the die.

[0004] In summary, the preparation of a high wear-resistant wire drawing die coating is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a high wear-resistant wire drawing die coating and its preparation process to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A process for preparing a high-wear-resistant wire drawing die coating includes the following steps: Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a transition layer and obtain wire drawing die A; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a wear-resistant coating to obtain a high wear-resistant wire drawing die coating.

[0007] In a more optimized manner, the mass ratio of the porous ceramic powder to the nickel-based self-fluxing alloy powder is (6~8):1.

[0008] The optimal laser cladding process conditions are: power 800~100W, scanning speed 3~5mm / s.

[0009] A more optimized method for preparing the porous ceramic powder is as follows: aluminum powder, silicon dioxide, phenolic resin, boron oxide, potassium chloride, and sodium chloride are uniformly mixed, sintered at 1400~1500℃ for 4~6 hours, cooled to 140~200℃, boric acid is added and stirring is continued, the temperature is raised to 400~500℃, washed with hot deionized water, and dried to obtain porous ceramic powder; the porosity of the porous ceramic powder is 25%~32%.

[0010] In a more optimized form, the raw materials for the porous ceramic powder include the following components: by mass parts, 40-50 parts aluminum powder, 20-25 parts silicon dioxide, 15-20 parts phenolic resin, 5-8 parts boron oxide, 10-15 parts potassium chloride, 10-15 parts sodium chloride, and 1-3 parts boric acid.

[0011] In this scheme, phenolic resin is used as a carbon source and auxiliary pore-forming agent. At high temperature, the phenolic resin forms amorphous carbon, which, together with aluminum powder, silicon dioxide, and boron oxide, mainly yields Al2O3-SiC-B4C at high temperature. The porosity of the porous ceramic powder is synergistically controlled by phenolic resin, sodium chloride, and potassium chloride, and boric acid is introduced for modification, forming B2O3 on the surface of the porous ceramic powder. This can synergize with nickel-based self-fluxing alloy powder to effectively improve the dispersibility of the porous ceramic powder under laser cladding and is beneficial to improving the bonding strength.

[0012] A more optimized method for preparing the Al2O3-Mo-based nanocomposite sol is as follows: (1) Tetraethyl orthosilicate, neopentyl glycol, and p-toluenesulfonic acid are mixed uniformly, heated to 80-100°C and kept at that temperature under a nitrogen atmosphere, then heated to 150-170°C and stirred for 2-4 hours to obtain polysiloxane; (2) Ammonium tetramolybdate, yttrium nitrate, and lanthanum nitrate are added to a citric acid aqueous solution, stirred and mixed, aluminum nitrate is added, pH is adjusted to 1-2, heated and stirred at 80-90°C, and when cooling down to 50-60°C, an aqueous solution of polysiloxane is added dropwise, stirred for 1-2 hours, cooled to room temperature, and aged to obtain Al2O3-Mo-based nanocomposite sol.

[0013] In a more optimized form, the raw materials for the polysiloxane include the following components: by mass, 100 parts of tetraethyl orthosilicate, 20-30 parts of neopentyl glycol, and 1-2 parts of p-toluenesulfonic acid; the raw materials for the Al2O3-Mo-based nanocomposite sol include the following components: by mass, 3-5 parts of ammonium tetramolybdate, 1-2 parts of yttrium nitrate, 1-2 parts of lanthanum nitrate, 50-80 parts of citric acid aqueous solution, 30-40 parts of aluminum nitrate, and 2-5 parts of polysiloxane; the particle size of the Al2O3-Mo-based nanocomposite sol is 90-135 nm.

[0014] In this scheme, citric acid acts as a complexing agent, forming stable chelate complexes with metal ions in ammonium tetramolybdate, yttrium nitrate, lanthanum nitrate, and aluminum nitrate, ensuring the stability of the sol. At 500-600℃, ammonium tetramolybdate decomposes into molybdenum oxide, yttrium nitrate into yttrium oxide, aluminum nitrate into aluminum oxide, and lanthanum nitrate into lanthanum oxide. When the temperature is raised to 980-1000℃ and hydrogen gas is introduced, molybdenum oxide is reduced to metallic molybdenum by hydrogen gas. Yttrium oxide and lanthanum oxide act as dopants, inhibiting the increase in particle size of aluminum oxide and metallic molybdenum. At high temperatures, amorphous aluminum oxide is converted into α-Al₂O₃, and polysiloxane is converted into silicon dioxide at high temperatures, filling the intergranular spaces of aluminum oxide in the form of a glassy phase, thereby improving the wear resistance and high-temperature stability of the composite material.

[0015] A more optimized curing process is as follows: under a nitrogen atmosphere, maintain the temperature at 80~120℃ for 2~4 hours, raise the temperature to 500~600℃ and maintain the temperature for 2~3 hours, then introduce hydrogen gas and raise the temperature to 980~1000℃ and maintain the temperature for 3~5 hours.

[0016] In a more optimized configuration, the high wear-resistant wire drawing die coating includes a transition layer and a wear-resistant coating; the thickness of the transition layer is 0.1~0.3mm; and the thickness of the wear-resistant coating is 0.06~0.1mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: In this scheme, porous ceramic powder and nickel-based self-fluxing alloy powder are mixed to obtain a transition layer powder; the transition layer is formed on the surface of the pre-treated wire drawing die by laser cladding to obtain wire drawing die A; Al2O3-Mo based nanocomposite sol is coated on its surface and cured to form a wear-resistant coating to obtain a high wear-resistant wire drawing die coating.

[0018] In the proposed solution, the difference in thermal expansion coefficients between the wire drawing die and the Al2O3-Mo-based nanocomposite sol leads to poor interfacial bonding between the two, thus affecting the wear resistance of the die. To address this issue, the proposed solution involves mixing porous ceramic powder and nickel-based self-fluxing alloy powder, followed by laser cladding to form a transition layer. Then, an Al2O3-Mo-based nanocomposite sol is coated onto the mixture. The Al2O3-Mo-based nanocomposite sol can penetrate into the porous ceramic powder. After sol curing, the interfacial bonding between the sol and the wire drawing die is effectively improved, thereby enhancing the wear resistance of the die.

[0019] In this solution, the drawing die is first sandblasted to improve the interfacial contact between the porous ceramic powder and the die. Nickel-based self-fluxing alloy powder and boron oxide act as binders. The nickel-based self-fluxing alloy powder has good interfacial bonding with the drawing die, allowing it to form a molten pool without excessively high temperatures, preventing the porous ceramic powder structure from collapsing due to high temperatures and reducing the penetration of Al2O3-Mo based nanocomposite sol. The boron oxide introduced onto the porous ceramic powder improves its dispersibility and, in conjunction with the surface sandblasting, greatly enhances the interfacial compatibility between the porous ceramic powder and the drawing die. However, the amount of nickel-based self-fluxing alloy powder added needs to be controlled. Excessive amounts may result in most of the pores in the porous ceramic powder being filled by the nickel-based self-fluxing alloy powder, affecting the subsequent penetration of the Al2O3-Mo based nanocomposite sol and thus impacting the performance of the high-wear-resistant drawing die. Detailed Implementation

[0020] 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.

[0021] 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: phenolic resin is phenolic resin 2130; TEOS (tetraethyl orthosilicate) CAS number is 78-10-4; NPG (neopentyl glycol) CAS number is 126-30-7; p-TSA (p-toluenesulfonic acid) CAS number is 104-15-4; yttrium nitrate CAS number is 13494-98-9; ammonium tetramolybdate CAS number is 12207-64-6; lanthanum nitrate CAS number is 100587-94-8; and nickel-based self-fluxing alloy powder is Ni60A.

[0022] In the following procedure, the H13 mold is immersed in 2M hydrochloric acid for ultrasonic cleaning for 1 minute, rinsed with water, dried, and sandblasted with 100-mesh abrasive to obtain a pre-treated wire drawing mold.

[0023] Example 1: A preparation process for a high wear-resistant wire drawing die coating includes the following steps: Pre-preparation: 40 parts aluminum powder, 20 parts silica, 18 parts phenolic resin, 6 parts boron oxide, 10 parts sodium chloride, and 10 parts potassium chloride were uniformly mixed and sintered at 1450℃ for 5 hours. The temperature was then lowered to 140℃, 1.5 parts boric acid were added, and stirring continued. The temperature was then raised to 400℃, rinsed with hot deionized water, and dried to obtain porous ceramic powder. The porosity of the porous ceramic powder was 29%. The preparation method of Al2O3-Mo based nanocomposite sol is as follows: (1) 100 parts of tetraethyl orthosilicate, 20 parts of neopentyl glycol and 1.3 parts of p-toluenesulfonic acid are mixed evenly, heated to 85°C under nitrogen atmosphere and kept warm until the by-product ethanol is evaporated, heated to 155°C and stirred for 3 hours, cooled to room temperature and vacuumed to obtain polysiloxane; (2) 5 parts of ammonium tetramolybdate, 1.5 parts of yttrium nitrate and 1.5 parts of lanthanum nitrate are added to 50 parts of citric acid aqueous solution (concentration is 3wt%), stirred and mixed, 40 parts of aluminum nitrate are added, pH is adjusted to 1.5, heated and stirred at 85°C for 3 hours, cooled to 50°C, and polysiloxane aqueous solution (4 parts of polysiloxane are added to 40 parts of deionized water and ultrasonically dispersed) is added dropwise, stirred for 2 hours, cooled to room temperature and aged to obtain Al2O3-Mo based nanocomposite sol; the particle size of Al2O3-Mo based nanocomposite sol is 115nm; Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 8:1 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.22mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0024] Example 2, a preparation process for a high wear-resistant wire drawing die coating, includes the following steps: Pre-preparation: 40 parts aluminum powder, 20 parts silica, 18 parts phenolic resin, 6 parts boron oxide, 10 parts sodium chloride, and 10 parts potassium chloride were uniformly mixed and sintered at 1450℃ for 5 hours. The temperature was then lowered to 140℃, 1.5 parts boric acid were added, and stirring continued. The temperature was then raised to 400℃, rinsed with hot deionized water, and dried to obtain porous ceramic powder. The porosity of the porous ceramic powder was 29%. The preparation method of Al2O3-Mo based nanocomposite sol is as follows: (1) 100 parts of tetraethyl orthosilicate, 20 parts of neopentyl glycol and 1.3 parts of p-toluenesulfonic acid are mixed evenly, heated to 85°C under nitrogen atmosphere and kept warm until the by-product ethanol is evaporated, heated to 155°C and stirred for 3 hours, cooled to room temperature and vacuumed to obtain polysiloxane; (2) 5 parts of ammonium tetramolybdate, 1.5 parts of yttrium nitrate and 1.5 parts of lanthanum nitrate are added to 50 parts of citric acid aqueous solution (concentration is 3wt%), stirred and mixed, 40 parts of aluminum nitrate are added, pH is adjusted to 1.5, heated and stirred at 85°C for 3 hours, cooled to 50°C, and polysiloxane aqueous solution (4 parts of polysiloxane are added to 40 parts of deionized water and ultrasonically dispersed) is added dropwise, stirred for 2 hours, cooled to room temperature and aged to obtain Al2O3-Mo based nanocomposite sol; the particle size of Al2O3-Mo based nanocomposite sol is 115nm; Step 1: (1) Porous ceramic powder and nickel-based self-fluxing alloy powder are mixed at a mass ratio of 7:1 to obtain transition layer powder; (2) The transition layer powder is laser-clad onto the surface of the pre-treated wire drawing die to form a 0.22mm transition layer, thus obtaining wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.078mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0025] Example 3: A preparation process for a high wear-resistant wire drawing die coating includes the following steps: Pre-preparation: 40 parts aluminum powder, 20 parts silica, 18 parts phenolic resin, 6 parts boron oxide, 10 parts sodium chloride, and 10 parts potassium chloride were uniformly mixed and sintered at 1450℃ for 5 hours. The temperature was then lowered to 140℃, 1.5 parts boric acid were added, and stirring continued. The temperature was then raised to 400℃, rinsed with hot deionized water, and dried to obtain porous ceramic powder. The porosity of the porous ceramic powder was 29%. The preparation method of Al2O3-Mo based nanocomposite sol is as follows: (1) 100 parts of tetraethyl orthosilicate, 20 parts of neopentyl glycol and 1.3 parts of p-toluenesulfonic acid are mixed evenly, heated to 85°C under nitrogen atmosphere and kept warm until the by-product ethanol is evaporated, heated to 155°C and stirred for 3 hours, cooled to room temperature and vacuumed to obtain polysiloxane; (2) 5 parts of ammonium tetramolybdate, 1.5 parts of yttrium nitrate and 1.5 parts of lanthanum nitrate are added to 50 parts of citric acid aqueous solution (concentration is 3wt%), stirred and mixed, 40 parts of aluminum nitrate are added, pH is adjusted to 1.5, heated and stirred at 85°C for 3 hours, cooled to 50°C, and polysiloxane aqueous solution (4 parts of polysiloxane are added to 40 parts of deionized water and ultrasonically dispersed) is added dropwise, stirred for 2 hours, cooled to room temperature and aged to obtain Al2O3-Mo based nanocomposite sol; the particle size of Al2O3-Mo based nanocomposite sol is 115nm; Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 6:1 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.1mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.065mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0026] Comparative Example 1 is based on Example 1, except that no transition layer is set; the rest of the operations are the same. Step 1: Coat the surface of the pre-treated wire drawing die with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0027] Comparative Example 2 was based on Example 1, but without the addition of yttrium nitrate and lanthanum oxide; all other operations were the same. Pre-preparation: The preparation method of Al2O3-Mo based nanocomposite sol is as follows: (1) 100 parts of tetraethyl orthosilicate, 20 parts of neopentyl glycol and 1.3 parts of p-toluenesulfonic acid are mixed evenly, heated to 85°C under nitrogen atmosphere and kept warm until the by-product ethanol is evaporated, heated to 155°C and stirred for 3 hours, cooled to room temperature and vacuumed to obtain polysiloxane; (2) 5 parts of ammonium tetramolybdate are added to 50 parts of citric acid aqueous solution (concentration is 3wt%), stirred and mixed, 40 parts of aluminum nitrate are added, pH is adjusted to 1.5, heated and stirred at 85°C for 3 hours, cooled to 50°C, and polysiloxane aqueous solution (4 parts of polysiloxane are added to 40 parts of deionized water and ultrasonically dispersed) is added dropwise, stirred for 2 hours, cooled to room temperature and aged to obtain Al2O3-Mo based nanocomposite sol; the particle size of Al2O3-Mo based nanocomposite sol is 115nm; Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 8:1 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.22mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0028] Comparative Example 3 is based on Example 1, but with an increased content of nickel-based self-fluxing alloy powder; the rest of the operations are the same. Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 8:5 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.22mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0029] Comparative Example 4 is based on Example 1, except that the phenolic resin is replaced with carbon black; the rest of the operations are the same. Pre-preparation: 40 parts aluminum powder, 20 parts silica, 18 parts carbon black, 6 parts boron oxide, 10 parts sodium chloride, and 10 parts potassium chloride were uniformly mixed and sintered at 1450℃ for 5 hours. The temperature was then lowered to 140℃, 1.5 parts boric acid were added, and stirring continued. The temperature was then raised to 400℃, rinsed with hot deionized water, and dried to obtain porous ceramic powder. The porosity of the porous ceramic powder was 20.3%. Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 8:1 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.22mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0030] Comparative Example 5 was based on Example 1, but boric acid was not introduced; the rest of the operations were the same. Pre-preparation: 40 parts aluminum powder, 20 parts silicon dioxide, 18 parts phenolic resin, 6 parts boron oxide, 10 parts sodium chloride, and 10 parts potassium chloride were mixed evenly and sintered at 1450℃ for 5 hours. After cooling to room temperature, the mixture was rinsed with hot deionized water and dried to obtain porous ceramic powder. Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 8:1 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.22mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0031] Comparative Example 6 is based on Example 1, but without the addition of polysiloxane; the remaining operating steps are the same. Pre-preparation: The Al2O3-Mo based nanocomposite sol was prepared as follows: 5 parts ammonium tetramolybdate, 1.5 parts yttrium nitrate, and 1.5 parts lanthanum nitrate were added to 50 parts citric acid aqueous solution (concentration 3wt%), stirred and mixed, 40 parts aluminum nitrate were added, the pH was adjusted to 1.5, and the mixture was heated and stirred at 85℃ for 3 hours. After cooling to room temperature, the mixture was aged to obtain Al2O3-Mo based nanocomposite sol; the particle size of the Al2O3-Mo based nanocomposite sol was 115 nm. Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder at a mass ratio of 8:1 to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a 0.22mm transition layer and obtain wire drawing die A; The laser cladding process conditions are: power 900W, scanning speed 3mm / s; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a 0.1mm wear-resistant coating to obtain a high wear-resistant wire drawing die coating; The curing process conditions are as follows: under a nitrogen atmosphere, hold at 85°C for 2 hours, raise the temperature to 500°C and hold for 2.5 hours, then introduce hydrogen and raise the temperature to 985°C and hold for 5 hours.

[0032] Test: (1) Test the friction coefficient of Examples 1 to 3; The test conditions are: silicon nitride as the grinding material, the loading force is 100N, the time is 1 hour, the speed is 2HZ, the spacing is 5mm, and the test temperature is 10℃; (2) The friction coefficients of Example 1 and Comparative Examples 1 to 6; The test conditions were: silicon nitride as the grinding material, the loading force was 100N, the time was 1 hour, the speed was 2HZ, the spacing was 5mm, and the test temperature was 500℃. (3) According to ASTM C-633-79, the surface of Example 1, Comparative Examples 1 to 6 and the paired tensile parts were roughened using a Z020 electronic universal testing machine, cleaned with alcohol, and then the coating and the paired tensile parts were bonded together using epoxy resin E-7 adhesive. The parts were kept at 100°C for 3.2 hours, cooled to room temperature, and tested using uniaxial tensile mode at a tensile speed of 2 mm / min.

[0033] Table 1 10℃, coefficient of friction Example 1 0.306 Example 2 0.315 Example 3 0.336

[0034] Table 2 500℃, coefficient of friction Bond strength (MPa) Example 1 0.462 65.817 Comparative Example 1 0.638 53.773 Comparative Example 2 0.487 58.582 Comparative Example 3 0.508 56.431 Comparative Example 4 0.473 63.563 Comparative Example 5 0.476 62.165 Comparative Example 6 0.537 60.647

[0035] Conclusions: Comparative Example 1 is based on Example 1, except that a transition layer was not provided; this resulted in a decrease in the bonding strength between the Al2O3-Mo based nanocomposite sol and the mold, thus affecting the performance of the mold. Comparative Example 2 is based on Example 1, but without the addition of yttrium nitrate and lanthanum oxide, resulting in larger particle sizes of Mo and Al2O3, reducing the density of the sol coating itself, thereby affecting the bonding between the Al2O3-Mo based nanocomposite sol and the porous ceramic powder, thus leading to a decrease in the bonding strength between the coating and the mold. Comparative Example 3 is based on Example 1, but with an increased content of nickel-based self-fluxing alloy powder; under laser cladding, more nickel-based self-fluxing alloy powder penetrated into the porous ceramic powder, affecting the bonding between the Al2O3-Mo based nanocomposite sol and the mold, thus leading to a decrease in performance.

[0036] Comparative Example 4 is based on Example 1, but the phenolic resin is replaced with carbon black. Phenolic resin not only serves as a carbon source but also generates gas at high temperatures to assist in pore formation. Furthermore, the amorphous carbon remaining after pyrolysis can improve the dispersion of the ceramic phase. In contrast, carbon black has poor pore-forming effect and insufficient dispersion, affecting the porosity of the porous ceramic powder and the subsequent bonding of Al2O3-Mo-based nanocomposite sol, thus leading to a decrease in performance. Comparative Example 5 is based on Example 1, but boric acid is not introduced. This results in a decrease in the dispersion of the porous ceramic powder, thus affecting the performance of the coating and the mold. Comparative Example 6 is based on Example 1, but polysiloxane is not added. Polysiloxane can improve the compatibility between the sol and the transition layer, and the silica glass phase generated after curing can fill the gaps in the coating. Without this component, the interfacial compatibility between the sol and the transition layer decreases, thus leading to a decrease in bonding strength.

[0037] 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 preparation process for a high wear-resistant wire drawing die coating, characterized in that: The following steps are included: Step 1: (1) Mix porous ceramic powder and nickel-based self-fluxing alloy powder to obtain transition layer powder; (2) Laser clad the transition layer powder on the surface of the pre-treated wire drawing die to form a transition layer and obtain wire drawing die A; Step 2: Coat the surface of wire drawing die A with Al2O3-Mo based nanocomposite sol, and cure to form a wear-resistant coating to obtain a high wear-resistant wire drawing die coating.

2. The preparation process of a high wear-resistant wire drawing die coating according to claim 1, characterized in that: The mass ratio of the porous ceramic powder to the nickel-based self-fluxing alloy powder is (6~8):

1.

3. The preparation process of a high wear-resistant wire drawing die coating according to claim 1, characterized in that: The laser cladding process conditions are: power 800~100W, scanning speed 3~5mm / s.

4. The preparation process of a high wear-resistant wire drawing die coating according to claim 1, characterized in that: The porous ceramic powder is prepared by uniformly mixing aluminum powder, silicon dioxide, phenolic resin, boron oxide, potassium chloride, and sodium chloride, sintering at 1400~1500℃ for 4~6 hours, cooling to 140~200℃, adding boric acid and continuing to stir, heating to 400~500℃, rinsing with hot deionized water, and drying to obtain porous ceramic powder.

5. The preparation process of a high wear-resistant wire drawing die coating according to claim 4, characterized in that: The raw materials of the porous ceramic powder include the following components: by mass parts, 40-50 parts aluminum powder, 20-25 parts silicon dioxide, 15-20 parts phenolic resin, 5-8 parts boron oxide, 10-15 parts potassium chloride, 10-15 parts sodium chloride, and 1-3 parts boric acid.

6. The preparation process of a high wear-resistant wire drawing die coating according to claim 1, characterized in that: The preparation method of the Al2O3-Mo-based nanocomposite sol is as follows: (1) Tetraethyl orthosilicate, neopentyl glycol and p-toluenesulfonic acid are mixed evenly, heated to 80~100℃ and kept at that temperature under a nitrogen atmosphere, then heated to 150~170℃ and stirred for 2~4 hours to obtain polysiloxane; (2) Ammonium tetramolybdate, yttrium nitrate and lanthanum nitrate are added to a citric acid aqueous solution, stirred and mixed, aluminum nitrate is added, pH is adjusted to 1~2, heated and stirred at 80~90℃, and when cooling down to 50~60℃, an aqueous solution of polysiloxane is added dropwise, stirred for 1~2 hours, cooled to room temperature, and aged to obtain Al2O3-Mo-based nanocomposite sol.

7. The preparation process of a high wear-resistant wire drawing die coating according to claim 6, characterized in that: The raw materials of the polysiloxane include the following components: by mass, 100 parts of tetraethyl orthosilicate, 20-30 parts of neopentyl glycol, and 1-2 parts of p-toluenesulfonic acid; the raw materials of the Al2O3-Mo-based nanocomposite sol include the following components: by mass, 3-5 parts of ammonium tetramolybdate, 1-2 parts of yttrium nitrate, 1-2 parts of lanthanum nitrate, 50-80 parts of citric acid aqueous solution, 30-40 parts of aluminum nitrate, and 2-5 parts of polysiloxane; the particle size of the Al2O3-Mo-based nanocomposite sol is 90-135 nm.

8. The preparation process of a high wear-resistant wire drawing die coating according to claim 1, characterized in that: The curing process conditions are as follows: under a nitrogen atmosphere, maintain the temperature at 80~120℃ for 2~4 hours, raise the temperature to 500~600℃ and maintain the temperature for 2~3 hours, then introduce hydrogen gas and raise the temperature to 980~1000℃ and maintain the temperature for 3~5 hours.

9. A high wear-resistant wire drawing die coating is prepared by a process according to any one of claims 1 to 8; characterized in that: The high wear-resistant wire drawing die coating includes a transition layer and a wear-resistant coating; the thickness of the transition layer is 0.1~0.3mm; the thickness of the wear-resistant coating is 0.06~0.1mm.