Wear-resistant ceramic lining plate and preparation method thereof

Abstract

The invention belongs to the technical field of ceramic lining plate preparation, and particularly relates to a wear-resistant ceramic lining plate and a preparation method thereof. The wear-resistant ceramic lining plate is prepared from the following raw materials: aluminum oxide, a sintering aid, aluminum titanate, modified urea resin microspheres, hafnium boride, tungsten disilicide and a KH-550 silane coupling agent, and the sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide and magnesium oxide. According to the wear-resistant ceramic lining plate, aluminum oxide serves as a main raw material, a mixture of niobium pentoxide, strontium oxide, lanthanum oxide and magnesium oxide serves as a sintering aid, a compound of modified urea-formaldehyde resin microspheres, hafnium boride and tungsten disilicide serves as a reinforcing and toughening phase, aluminum titanate serves as a conditioning agent, and the raw materials have a synergistic effect; and it is ensured that the prepared ceramic lining plate has good wear resistance, hardness and toughness.

Description

Technical Field

[0001] This invention belongs to the field of ceramic liner preparation technology, specifically relating to a wear-resistant ceramic liner and its preparation method. Background Technology

[0002] In the transportation and storage processes of ore dressing plants, wear-resistant liners are commonly used to address wear issues in equipment, pipelines, chutes, and silos. Materials typically include cast stone, high-chromium cast iron, alumina ceramics, and ultra-high molecular weight polyethylene. Because the materials washed and processed in ore dressing plants have a high Mohs hardness, they cause severe wear on the linings of equipment, chutes, and silos, increasing maintenance workload and posing significant safety hazards. Therefore, improving the wear resistance and impact resistance of equipment liners is crucial.

[0003] Commonly used wear-resistant materials for lining plates include: ① High-chromium cast iron: High-chromium cast iron refers to a wear-resistant material with a carbon content of 0.6%-2% and a chromium content of 13%-25%. It has high hardness but is also brittle. Under the impact of large particles or the vibration of equipment during start-up and shutdown, it is prone to chipping and breakage and cannot withstand heavy impact loads. ② Cast stone: Cast stone is a non-metallic wear-resistant material with fine and dense grains, made primarily from natural rocks such as gray-green rock or basalt, with a small amount of additives. It is produced through high-temperature melting, casting, crystallization annealing, and other processes. It has good wear resistance, but the thickness of the lining plate after molding is large, which will occupy the effective volume of the equipment. In addition, defects such as uneven density and internal shrinkage cavities are prone to occur during the casting process. Under long-term impact, internal cracks are prone to propagate and lead to failure. ③ Ultra-high molecular weight polyethylene: Ultra-high molecular weight polyethylene is a thermoplastic engineering plastic with good self-lubricating properties and impact strength. However, its heat resistance is low, and the temperature rise caused by friction and extrusion during material transportation in ore processing plants easily leads to softening and deformation. Furthermore, its low hardness results in rapid wear and short service life under long-term erosion from high-hardness ores. Additionally, it is prone to plastic deformation, denting, and even tearing under the impact of large-particle ores with high drops, failing to meet the requirements of high-intensity impact conditions. ④ Alumina ceramics: Alumina ceramics are made by uniformly mixing Al2O3 micro-powder (below 100 mesh) with various wear-resistant materials, then dry-pressing or isostatically pressing it into blanks using a 100t press, followed by sintering at 1700℃. While alumina ceramics possess good hardness and wear resistance, they are brittle and easily break and detach under strong impacts.

[0004] Therefore, it is necessary to explore a new type of wear-resistant ceramic liner for the harsh working conditions of ore dressing plants, which involve high drops, large particles, and strong impacts. Summary of the Invention

[0005] The purpose of this invention is to provide a wear-resistant ceramic liner, which has good wear resistance and toughness. In addition, this invention also provides a method for its preparation.

[0006] The wear-resistant ceramic liner of the present invention is composed of the following raw materials in parts by weight: 100 parts alumina, 3.8-4.2 parts sintering aid, 5-7 parts aluminum titanate, 3-4 parts modified urea-formaldehyde resin microspheres, 4-6 parts hafnium boride, 1.5-1.7 parts tungsten disilicide, and 0.8-1.0 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide. The modified urea-formaldehyde resin... The preparation method of lipid microspheres consists of the following steps: ① preparation of metal salt-citric acid complex solution; ② preparation of urea-formaldehyde prepolymer solution; ③ pouring the urea-formaldehyde prepolymer solution into a reaction vessel, adding the metal salt-citric acid complex solution dropwise while stirring at room temperature, adjusting the pH of the system to 5.5, and continuing stirring until the complexation is complete; ④ preparing a gel solution through polycondensation reaction; ⑤ curing and molding the oil phase; ⑥ washing, drying, and sieving to prepare modified urea-formaldehyde resin microspheres.

[0007] The mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide in the sintering aid is 0.5:1:2:2.

[0008] The preparation method of the modified urea-formaldehyde resin microspheres includes step ①, the preparation of the metal salt-citric acid complex solution, which is as follows: citric acid and water-soluble phenolic resin are added to deionized water accounting for 35% of the total mass of deionized water and stirred at 40°C and 300 r / min for 15 min. Niobium oxalate is added and stirred for 15 min. Ammonium heptamolybdate tetrahydrate is added and stirred for 10 min. Chromium nitrate is added and stirred for 10 min. Finally, deionized water accounting for 65% of the total mass of deionized water is added and stirred until clear to obtain the metal salt-citric acid complex solution.

[0009] In step ①, the molar ratio of the metal elements in niobium oxalate, ammonium heptamolybdate tetrahydrate, and chromium nitrate is 3:4:2, and the total metal ion concentration in the deionized water is controlled to be 0.67 mol / L.

[0010] In step ①, the ratio of the sum of the amounts of molybdenum in niobium oxalate, chromium nitrate, and ammonium heptamolybdate tetrahydrate to the amount of citric acid in the metal salt-citric acid complex solution is 1:1.4.

[0011] In step ①, the ratio of the sum of the amounts of molybdenum in niobium oxalate, chromium nitrate, and ammonium heptamolybdate tetrahydrate to the amount of water-soluble phenolic resin in the preparation of the metal salt-citric acid complex solution is 1:1.8.

[0012] In step ①, the water-soluble phenolic resin used in the preparation of the metal salt-citric acid complex solution was manufactured by Shandong Jiaying Chemical Technology Co., Ltd., and its model number was YHY5213.

[0013] Step ② Preparation of urea-formaldehyde prepolymer solution is as follows: Dissolve urea in deionized water and stir at room temperature until completely dissolved. Then add formaldehyde solution and continue stirring and mixing for 17 minutes to prepare urea-formaldehyde prepolymer solution. The molar ratio of urea to formaldehyde is 1:1.6, the mass concentration of formaldehyde solution is 37%, and the mass ratio of urea to deionized water is 1:0.92.

[0014] Step ③ is as follows: Pour the urea-formaldehyde prepolymer solution into a reaction vessel and stir at 350 r / min at room temperature. Add the metal salt-citric acid complex solution dropwise at a rate of 5 mL / min for 30 min. Then, add 1 mol / L NaOH solution to adjust the pH of the system to 5.5. Adjust the stirring speed to 300 r / min and continue stirring for 60 min until the complexation is complete. The volume ratio of the urea-formaldehyde prepolymer solution to the metal salt-citric acid complex solution is 0.83:1.

[0015] Step ④ describes the preparation of the gel solution via polycondensation reaction as follows: The temperature of the reaction system is raised from room temperature to 80°C within 15 minutes at a rotation speed of 300 r / min. Then, the rotation speed is adjusted to 250 r / min, and the reaction is continuously stirred at 80°C for 60 minutes. Stirring is then stopped, and the polycondensation reaction is complete. The criterion for determining the completion of the polycondensation reaction is the droplet method: a dropper is used to take a portion of the gel solution and drop it into cold water. If the solution forms a complete sphere that does not disperse or spread, and remains intact without breaking, the reaction is considered complete.

[0016] The oil phase curing and molding process in step ⑤ is as follows: using liquid paraffin as the oil phase, the syringe draws in the gel liquid, removes air bubbles, and fixes it vertically with a 21G needle (0.5mm inner diameter), with the needle 4cm away from the liquid paraffin. The dripping speed is controlled at 30 drops / min, and the gel liquid is dripped into the liquid paraffin. The liquid immediately shrinks into a ball after being added to the oil. After the dripping is completed, it is first allowed to stand and cure in the liquid paraffin for 2.5h at a standing curing temperature of 77℃, and then allowed to cool naturally to room temperature.

[0017] The washing, drying, and sieving process described in step ⑥ to prepare modified urea-formaldehyde resin microspheres is as follows: After the microspheres are taken out, they are first washed three times with petroleum ether at 75°C for 10 minutes each time, then washed three times with anhydrous ethanol for 10 minutes each time, and finally washed once with deionized water for 8 minutes. They are then naturally air-dried at 25°C for 20 hours, dried at 41°C for 12 hours, dried at 61°C for 10 hours, and dried at 82°C for 8 hours. Finally, they are graded using standard sieves, and the microspheres that pass through a 14-mesh sieve but are retained between 18-mesh sieves are collected.

[0018] The method for preparing the wear-resistant ceramic liner of the present invention comprises the following steps: (1) Mix KH-550 silane coupling agent, deionized water and ethanol, add acetic acid to adjust the pH of the system to 4.0, stir and hydrolyze at room temperature for 30-35 min to prepare hydrolysate; (2) Add alumina, aluminum titanate, hafnium boride and sintering aid to a ball mill jar, add hydrolysate and ball mill for 35-40 min, then add modified urea-formaldehyde resin microspheres and continue ball milling for 30-35 min, finally add deionized water and tungsten disilicide and continue ball milling for 25-30 min to prepare a slurry; (3) The slurry was dried in a vacuum drying oven and then ground through a 200-mesh sieve to obtain granulated powder; (4) The granulated powder is filled into the mold and dry-pressed to obtain the green body; (5) Place the blank in a graphite mold, put it into a hot press furnace and evacuate it. First, heat it to 200℃ at a heating rate of 5℃ / min and hold it for 30min. Then, heat it to 600-610℃ at a heating rate of 2℃ / min and hold it for 30min. Then, fill the furnace with argon gas to a pressure of 0.25MPa and heat it to 1100-1105℃ at a heating rate of 5℃ / min. Within 20min, apply axial mechanical pressure to 35MPa. Under the condition of maintaining this pressure, heat it to 1650-1680℃ at a heating rate of 5℃ / min and hold it for 1.5h. After the holding is completed, cool it to room temperature with the furnace under the condition of maintaining a pressure of 35MPa. After demolding, wear-resistant ceramic liner is obtained.

[0019] In step (1), the mass ratio of KH-550 silane coupling agent, ethanol, and deionized water is 1:144:16.

[0020] In step (2), alumina, aluminum titanate, hafnium boride and sintering aid are added to a ball mill jar, and hydrolysate is added and ball milled for 35-40 min at a speed of 250 r / min. Then, modified urea-formaldehyde resin microspheres are added and ball milling continues for 30-35 min at a speed of 150 r / min. Finally, deionized water and tungsten disilicide are added and ball milling continues for 25-30 min at a speed of 150 r / min to prepare a slurry. Zirconia balls with a diameter of 1 mm are selected as the grinding medium throughout the ball milling process.

[0021] In step (2), deionized water is added to adjust and control the solid content of the slurry to 55-60%.

[0022] In step (3), the vacuum drying temperature is 60℃ and the vacuum drying time is 5.5-6h.

[0023] In step (4), the pressure for dry pressing is 180 MPa and the time for dry pressing is 15 s.

[0024] Compared with the prior art, the present invention has the following advantages: (1) The wear-resistant ceramic liner of the present invention uses alumina as the main raw material, a mixture of niobium pentoxide, strontium oxide, lanthanum oxide and magnesium oxide as sintering aid, a composite of modified urea-formaldehyde resin microspheres, hafnium boride and tungsten disilicide as reinforcing and toughening phase, and aluminum titanate as a regulator. The synergistic effect between the raw materials ensures that the prepared ceramic liner has good wear resistance, hardness and toughness.

[0025] (2) The wear-resistant ceramic liner of the present invention uses modified urea-formaldehyde resin microspheres, hafnium boride, and tungsten disilicide as toughening and reinforcing phases. The newly generated carbide phase after high-temperature pyrolysis of the modified urea-formaldehyde resin microspheres forms a chemical bonding interface with the alumina matrix. When the crack extends to this area, these in-situ generated hard phases hinder crack penetration through the interface pinning effect and produce "crack bridging" and "pull-out toughening" effects under stress, thereby improving the toughness of the material. Hafnium boride, as a high-hardness high-temperature ceramic reinforcing phase, improves the hardness and wear resistance of the ceramic liner, plays a role in dispersion strengthening and grain refinement, hinders abnormal growth of alumina grains, and improves the density of the material. Tungsten disilicide remains stable in a solid state during high-temperature sintering and does not undergo thermal decomposition. Its coefficient of thermal expansion is highly matched with that of the alumina matrix, effectively reducing thermal stress. WSi2, as a high-hardness dispersion strengthening phase, is uniformly distributed at the grain boundaries, playing a role in grain boundary pinning and dispersion strengthening, improving the high-temperature hardness and creep resistance of the ceramic liner. In addition, aluminum titanate is added to the raw materials. Aluminum titanate has an extremely low coefficient of thermal expansion, forming a thermal expansion gradient with the alumina matrix. During sintering and cooling, this gradient design can alleviate thermal stress concentration and reduce the risk of cracking of the liner due to thermal stress from the source. At the same time, some of the decomposition products of aluminum titanate at high temperatures (corundum + rutile) are compatible with the matrix and do not introduce harmful impurities.

[0026] (3) The mechanism by which the modified urea-formaldehyde resin microspheres function in the wear-resistant ceramic liner of the present invention is as follows: Water-soluble phenolic resin acts as a carbon source. Under a high-temperature inert atmosphere, the phenolic resin undergoes pyrolysis, forming a carbon-rich amorphous carbon network. This carbon encapsulates the metal salt particles. The original urea-formaldehyde resin skeleton decomposes, releasing ammonia, carbon dioxide, and water vapor. Due to the large number of pores inside the microspheres, this part of the skeleton leaves a porous structure, providing a reaction channel for subsequent carbothermic reduction. Among them, niobium oxalate decomposes under a high-temperature inert atmosphere to generate niobium oxide (Nb2O5), which then undergoes a carbothermic reduction reaction with the excess phenolic resin cracked carbon in the system. The in-situ generated niobium carbide (NbC) has extremely high hardness and excellent high-temperature stability. As a dispersed hard ceramic reinforcing phase, it can effectively hinder the propagation of microcracks and improve the toughness of ceramic materials. Chromium nitrate decomposes under a high-temperature inert atmosphere to form Cr2O3, which then undergoes a carbothermic reduction reaction with excess phenolic resin cracked carbon in the system, generating Cr3C2 in situ. This Cr3C2 further transforms into a chromium carbide complex phase at high temperature, providing high-temperature wear resistance and corrosion resistance. Ammonium heptamolybdate tetrahydrate decomposes under a high-temperature inert atmosphere to form molybdenum oxide, which then undergoes a carbothermic reduction reaction with excess phenolic resin cracked carbon in the system, generating MO2C in situ. This MO2C further transforms into a high-carbide phase during subsequent high-temperature sintering, exerting its toughening and buffering effect. Therefore, the synergistic effect of the three metals in the modified urea-formaldehyde resin, when added to wear-resistant ceramic liners, provides the following benefits: niobium carbide's high hardness provides basic wear resistance; molybdenum carbide's toughness adjustment ability absorbs impact energy through its limited plastic deformation, inhibiting crack initiation and propagation; and chromium carbide provides interfacial stability and corrosion resistance.

[0027] (4) The wear-resistant ceramic liner of the present invention uses a mixture of niobium pentoxide, strontium oxide, lanthanum oxide and magnesium oxide as sintering aids. Magnesium oxide can inhibit abnormal growth of alumina grains during sintering, refine grain size, reduce grain boundary defects and internal pores, and improve ceramic density. Lanthanum oxide can promote the formation of a low-viscosity grain boundary liquid phase, reduce sintering temperature and accelerate densification process. On the other hand, it can generate a stable lanthanum aluminate reinforcing phase at the grain boundary, effectively strengthen the grain boundary, improve the fracture toughness of the ceramic, and reduce edge chipping and peeling during use. Strontium oxide forms a low-melting-point composite liquid phase with other components in the system, further reducing sintering activation energy, adjusting the grain boundary phase composition and thermal expansion matching, reducing internal residual stress, and improving the structural integrity and dimensional stability of the wear-resistant ceramic liner. Niobium pentoxide can partially dissolve into the alumina lattice, causing lattice distortion to achieve dispersion strengthening. At the same time, it forms a high-temperature stable niobate compound at the grain boundary, improving the high-temperature strength and creep resistance of the grain boundary, and enhancing the abrasive wear resistance of the ceramic. The combination of these four components can result in a dense structure, fine and uniform grains, and stable performance in wear-resistant ceramic liners.

[0028] (5) The method for preparing the wear-resistant ceramic liner of the present invention is simple, the parameters are easy to achieve, and the performance of the prepared wear-resistant ceramic liner is stable. Detailed Implementation

[0029] The preparation method of modified urea-formaldehyde resin microspheres used in the following examples and comparative examples consists of the following steps: ① Preparation of metal salt-citric acid complex solution; ② Preparation of urea-formaldehyde prepolymer solution; ③ Pour the urea-formaldehyde prepolymer solution into a reaction vessel, add the metal salt-citric acid complex solution dropwise while stirring at room temperature, adjust the pH of the system to 5.5, and continue stirring until the complexation is complete; ④ Prepare a gel solution through polycondensation reaction; ⑤ Cure the oil phase; ⑥ Wash, dry, and sieve to prepare modified urea-formaldehyde resin microspheres.

[0030] The preparation method of the modified urea-formaldehyde resin microspheres includes step ①, the preparation of the metal salt-citric acid complex solution, which is as follows: citric acid and water-soluble phenolic resin are added to deionized water accounting for 35% of the total mass of deionized water and stirred at 40°C and 300 r / min for 15 min. Niobium oxalate is added and stirred for 15 min. Ammonium heptamolybdate tetrahydrate is added and stirred for 10 min. Chromium nitrate is added and stirred for 10 min. Finally, deionized water accounting for 65% of the total mass of deionized water is added and stirred until clear to obtain the metal salt-citric acid complex solution.

[0031] In step ①, the molar ratio of the metal elements in niobium oxalate, ammonium heptamolybdate tetrahydrate, and chromium nitrate is 3:4:2, and the total metal ion concentration in the deionized water is controlled to be 0.67 mol / L.

[0032] In step ①, the ratio of the sum of the amounts of molybdenum in niobium oxalate, chromium nitrate, and ammonium heptamolybdate tetrahydrate to the amount of citric acid in the metal salt-citric acid complex solution is 1:1.4.

[0033] In step ①, the ratio of the sum of the amounts of molybdenum in niobium oxalate, chromium nitrate, and ammonium heptamolybdate tetrahydrate to the amount of water-soluble phenolic resin in the preparation of the metal salt-citric acid complex solution is 1:1.8.

[0034] In step ①, the water-soluble phenolic resin used in the preparation of the metal salt-citric acid complex solution was manufactured by Shandong Jiaying Chemical Technology Co., Ltd., and its model number was YHY5213.

[0035] Step ② Preparation of urea-formaldehyde prepolymer solution is as follows: Dissolve urea in deionized water and stir at room temperature until completely dissolved. Then add formaldehyde solution and continue stirring and mixing for 17 minutes to prepare urea-formaldehyde prepolymer solution. The molar ratio of urea to formaldehyde is 1:1.6, the mass concentration of formaldehyde solution is 37%, and the mass ratio of urea to deionized water is 1:0.92.

[0036] Step ③ is as follows: Pour the urea-formaldehyde prepolymer solution into a reaction vessel and stir at 350 r / min at room temperature. Add the metal salt-citric acid complex solution dropwise at a rate of 5 mL / min for 30 min. Then, add 1 mol / L NaOH solution to adjust the pH of the system to 5.5. Adjust the stirring speed to 300 r / min and continue stirring for 60 min until the complexation is complete. The volume ratio of the urea-formaldehyde prepolymer solution to the metal salt-citric acid complex solution is 0.83:1.

[0037] Step ④ describes the preparation of the gel solution via polycondensation reaction as follows: The temperature of the reaction system is raised from room temperature to 80°C within 15 minutes at a rotation speed of 300 r / min. Then, the rotation speed is adjusted to 250 r / min, and the reaction is continuously stirred at 80°C for 60 minutes. Stirring is then stopped, and the polycondensation reaction is complete. The criterion for determining the completion of the polycondensation reaction is the droplet method: a dropper is used to take a portion of the gel solution and drop it into cold water. If the solution forms a complete sphere that does not disperse or spread, and remains intact without breaking, the reaction is considered complete.

[0038] The oil phase curing and molding process in step ⑤ is as follows: using liquid paraffin as the oil phase, the syringe draws in the gel liquid, removes air bubbles, and fixes it vertically with a 21G needle (0.5mm inner diameter), with the needle 4cm away from the liquid paraffin. The dripping speed is controlled at 30 drops / min, and the gel liquid is dripped into the liquid paraffin. The liquid immediately shrinks into a ball after being added to the oil. After the dripping is completed, it is first allowed to stand and cure in the liquid paraffin for 2.5h at a standing curing temperature of 77℃, and then allowed to cool naturally to room temperature.

[0039] The washing, drying, and sieving process described in step ⑥ to prepare modified urea-formaldehyde resin microspheres is as follows: After the microspheres are taken out, they are first washed three times with petroleum ether at 75°C for 10 minutes each time, then washed three times with anhydrous ethanol for 10 minutes each time, and finally washed once with deionized water for 8 minutes. They are then naturally air-dried at 25°C for 20 hours, dried at 41°C for 12 hours, dried at 61°C for 10 hours, and dried at 82°C for 8 hours. Finally, they are graded using standard sieves, and the microspheres that pass through a 14-mesh sieve but are retained between 18-mesh sieves are collected.

[0040] Example 1 The wear-resistant ceramic liner described in Example 1 is composed of the following raw materials by weight: 100 parts alumina, 4.0 parts sintering aid, 6 parts aluminum titanate, 3.5 parts modified urea-formaldehyde resin microspheres, 5 parts hafnium boride, 1.6 parts tungsten disilicide, and 0.9 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide. The preparation method of the modified urea-formaldehyde resin microspheres comprises the following steps: ① preparation of a metal salt-citric acid complex solution; ② preparation of a urea-formaldehyde prepolymer solution; ③ pouring the urea-formaldehyde prepolymer solution into a reaction vessel, adding the metal salt-citric acid complex solution dropwise while stirring at room temperature, adjusting the pH of the system to 5.5, and continuing stirring until complete complexation; ④ preparing a gel solution through a condensation reaction; ⑤ curing and molding the oil phase; ⑥ washing, drying, and sieving to obtain modified urea-formaldehyde resin microspheres.

[0041] The mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide in the sintering aid is 0.5:1:2:2.

[0042] The method for preparing the wear-resistant ceramic liner of the present invention in Embodiment 1 consists of the following steps: (1) Mix KH-550 silane coupling agent, deionized water and ethanol, add acetic acid to adjust the pH of the system to 4.0, stir and hydrolyze at room temperature for 33 min to prepare hydrolysate; (2) Add alumina, aluminum titanate, hafnium boride and sintering aid to a ball mill jar, add hydrolysate and ball mill for 37 min, then add modified urea-formaldehyde resin microspheres and continue ball milling for 33 min, finally add deionized water and tungsten disilicide and continue ball milling for 27 min to prepare a slurry; (3) The slurry was dried in a vacuum drying oven and then ground through a 200-mesh sieve to obtain granulated powder; (4) The granulated powder is filled into the mold and dry-pressed to obtain the green body; (5) Place the blank in a graphite mold, put it into a hot press furnace and evacuate it. First, heat it to 200℃ at a heating rate of 5℃ / min and hold it for 30min. Then, heat it to 605℃ at a heating rate of 2℃ / min and hold it for 30min. Then, fill the furnace with argon gas to a pressure of 0.25MPa and heat it to 1103℃ at a heating rate of 5℃ / min. Within 20min, apply axial mechanical pressure to 35MPa. Under the condition of maintaining this pressure, heat it to 1665℃ at a heating rate of 5℃ / min and hold it for 1.5h. After the holding period, cool it to room temperature with the furnace while maintaining a pressure of 35MPa. After demolding, wear-resistant ceramic liner is obtained.

[0043] In step (1), the mass ratio of KH-550 silane coupling agent, ethanol, and deionized water is 1:144:16.

[0044] In step (2), alumina, aluminum titanate, hafnium boride and sintering aid are added to a ball mill jar, hydrolysate is added and ball milling is performed for 37 min at a speed of 250 r / min. Then, modified urea-formaldehyde resin microspheres are added and ball milling is continued for 33 min at a speed of 150 r / min. Finally, deionized water and tungsten disilicide are added and ball milling is continued for 27 min at a speed of 150 r / min to prepare a slurry. Zirconia balls with a diameter of 1 mm are selected as the grinding medium throughout the ball milling process.

[0045] In step (2), deionized water is added to adjust and control the solid content of the slurry to 57%.

[0046] In step (3), the vacuum drying temperature is 60℃ and the vacuum drying time is 5.7h.

[0047] In step (4), the pressure for dry pressing is 180 MPa and the time for dry pressing is 15 s.

[0048] Example 2 The wear-resistant ceramic liner described in Example 2 is composed of the following raw materials by weight: 100 parts alumina, 3.8 parts sintering aid, 5 parts aluminum titanate, 4 parts modified urea-formaldehyde resin microspheres, 4 parts hafnium boride, 1.7 parts tungsten disilicide, and 0.8 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide. The preparation method of the modified urea-formaldehyde resin microspheres comprises the following steps: ① preparation of a metal salt-citric acid complex solution; ② preparation of a urea-formaldehyde prepolymer solution; ③ pouring the urea-formaldehyde prepolymer solution into a reaction vessel, adding the metal salt-citric acid complex solution dropwise while stirring at room temperature, adjusting the pH of the system to 5.5, and continuing stirring until complete complexation; ④ preparing a gel solution through a condensation reaction; ⑤ curing and molding the oil phase; ⑥ washing, drying, and sieving to obtain modified urea-formaldehyde resin microspheres.

[0049] The mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide in the sintering aid is 0.5:1:2:2.

[0050] The method for preparing the wear-resistant ceramic liner of this embodiment 2 consists of the following steps: (1) Mix KH-550 silane coupling agent, deionized water and ethanol, add acetic acid to adjust the pH of the system to 4.0, stir and hydrolyze at room temperature for 30 min to prepare hydrolysate; (2) Add alumina, aluminum titanate, hafnium boride and sintering aid to a ball mill jar, add hydrolysate and ball mill for 35 min, then add modified urea-formaldehyde resin microspheres and continue ball milling for 35 min, finally add deionized water and tungsten disilicide and continue ball milling for 25 min to prepare a slurry; (3) The slurry was dried in a vacuum drying oven and then ground through a 200-mesh sieve to obtain granulated powder; (4) The granulated powder is filled into the mold and dry-pressed to obtain the green body; (5) Place the blank in a graphite mold, put it into a hot press furnace and evacuate it. First, heat it to 200℃ at a heating rate of 5℃ / min and hold it for 30min. Then, heat it to 600℃ at a heating rate of 2℃ / min and hold it for 30min. Then, fill the furnace with argon gas to a pressure of 0.25MPa and heat it to 1105℃ at a heating rate of 5℃ / min. Within 20min, apply axial mechanical pressure to 35MPa. Under the condition of maintaining this pressure, heat it to 1650℃ at a heating rate of 5℃ / min and hold it for 1.5h. After the holding is completed, cool it to room temperature with the furnace under the condition of maintaining a pressure of 35MPa. After demolding, wear-resistant ceramic liner is obtained.

[0051] In step (1), the mass ratio of KH-550 silane coupling agent, ethanol, and deionized water is 1:144:16.

[0052] In step (2), alumina, aluminum titanate, hafnium boride and sintering aid are added to a ball mill jar, hydrolysate is added and ball milling is performed for 35 minutes at a speed of 250 r / min. Then, modified urea-formaldehyde resin microspheres are added and ball milling is continued for 35 minutes at a speed of 150 r / min. Finally, deionized water and tungsten disilicide are added and ball milling is continued for 25 minutes at a speed of 150 r / min to prepare a slurry. Zirconia balls with a diameter of 1 mm are selected as the grinding medium throughout the ball milling process.

[0053] In step (2), deionized water is added to adjust and control the solid content of the slurry to 55%.

[0054] In step (3), the vacuum drying temperature is 60℃ and the vacuum drying time is 5.5h.

[0055] In step (4), the pressure for dry pressing is 180 MPa and the time for dry pressing is 15 s.

[0056] Example 3 The wear-resistant ceramic liner described in Example 3 is composed of the following raw materials by weight: 100 parts alumina, 4.2 parts sintering aid, 7 parts aluminum titanate, 3 parts modified urea-formaldehyde resin microspheres, 6 parts hafnium boride, 1.5 parts tungsten disilicide, and 1.0 part KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide. The preparation method of the modified urea-formaldehyde resin microspheres comprises the following steps: ① preparation of a metal salt-citric acid complex solution; ② preparation of a urea-formaldehyde prepolymer solution; ③ pouring the urea-formaldehyde prepolymer solution into a reaction vessel, adding the metal salt-citric acid complex solution dropwise while stirring at room temperature, adjusting the pH of the system to 5.5, and continuing stirring until complete complexation; ④ preparing a gel solution through a condensation reaction; ⑤ curing and molding the oil phase; ⑥ washing, drying, and sieving to obtain modified urea-formaldehyde resin microspheres.

[0057] The mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide in the sintering aid is 0.5:1:2:2.

[0058] The method for preparing the wear-resistant ceramic liner described in Embodiment 3 of this invention comprises the following steps: (1) Mix KH-550 silane coupling agent, deionized water and ethanol, add acetic acid to adjust the pH of the system to 4.0, stir and hydrolyze at room temperature for 35 min to prepare hydrolysate; (2) Add alumina, aluminum titanate, hafnium boride and sintering aid to a ball mill jar, add hydrolysate and ball mill for 40 min, then add modified urea-formaldehyde resin microspheres and continue ball milling for 30 min, and finally add deionized water and tungsten disilicide and continue ball milling for 30 min to prepare a slurry. (3) The slurry was dried in a vacuum drying oven and then ground through a 200-mesh sieve to obtain granulated powder; (4) The granulated powder is filled into the mold and dry-pressed to obtain the green body; (5) Place the blank in a graphite mold, put it into a hot press furnace and evacuate it. First, heat it to 200℃ at a heating rate of 5℃ / min and hold it for 30min. Then, heat it to 610℃ at a heating rate of 2℃ / min and hold it for 30min. Then, fill the furnace with argon gas to a pressure of 0.25MPa and heat it to 1100℃ at a heating rate of 5℃ / min. Within 20min, apply axial mechanical pressure to 35MPa. Under the condition of maintaining this pressure, heat it to 1680℃ at a heating rate of 5℃ / min and hold it for 1.5h. After the holding period, cool it to room temperature with the furnace while maintaining a pressure of 35MPa. After demolding, wear-resistant ceramic liner is obtained.

[0059] In step (1), the mass ratio of KH-550 silane coupling agent, ethanol, and deionized water is 1:144:16.

[0060] In step (2), alumina, aluminum titanate, hafnium boride and sintering aid are added to a ball mill jar, hydrolysate is added and ball milling is performed for 40 minutes at a speed of 250 r / min. Then, modified urea-formaldehyde resin microspheres are added and ball milling is continued for 30 minutes at a speed of 150 r / min. Finally, deionized water and tungsten disilicide are added and ball milling is continued for 30 minutes at a speed of 150 r / min to prepare a slurry. Zirconia balls with a diameter of 1 mm are selected as the grinding medium throughout the ball milling process.

[0061] In step (2), deionized water is added to adjust and control the solid content of the slurry to 60%.

[0062] In step (3), the vacuum drying temperature is 60℃ and the vacuum drying time is 6h.

[0063] In step (4), the pressure for dry pressing is 180 MPa and the time for dry pressing is 15 s.

[0064] Comparative Example 1 The preparation method of the wear-resistant ceramic liner in Comparative Example 1 is the same as that in Example 1, except that the raw material composition is different. The wear-resistant ceramic liner in Comparative Example 1 is composed of the following raw materials by weight: 100 parts alumina, 4.0 parts sintering aid, 6 parts aluminum titanate, 5 parts hafnium boride, 1.6 parts tungsten disilicide, and 0.9 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide, and the mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide is 0.5:1:2:2.

[0065] Comparative Example 2 The preparation method of the wear-resistant ceramic liner in Comparative Example 2 is the same as that in Example 1, except that the raw material composition is different. The wear-resistant ceramic liner in Comparative Example 2, by weight, consists of the following raw materials: 100 parts alumina, 4.0 parts sintering aid, 6 parts aluminum titanate, 3.5 parts modified urea-formaldehyde resin microspheres, 1.6 parts tungsten disilicide, and 0.9 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide, with a mass ratio of 0.5:1:2:2.

[0066] Comparative Example 3 The preparation method of the wear-resistant ceramic liner described in Comparative Example 3 is the same as that in Example 1, except that the raw material composition is different. The wear-resistant ceramic liner described in Comparative Example 3, by weight, is composed of the following raw materials: 100 parts alumina, 4.0 parts sintering aid, 6 parts aluminum titanate, 3.5 parts modified urea-formaldehyde resin microspheres, 5 parts hafnium boride, and 0.9 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide, and the mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide is 0.5:1:2:2.

[0067] The wear-resistant ceramic liners prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance testing. Hardness testing was performed on the ceramic liners according to GB / T 16534 "Test Method for Room Temperature Hardness of Fine Ceramics"; wear volume testing was performed on the ceramic liners according to GB / T 27979 "Alumina Wear-Resistant Ceramic Composite Liners"; fracture toughness testing was performed on the ceramic liners according to GB / T 23806 "Test Method for Fracture Toughness of Fine Ceramics - Single-Sided Pre-Cracked Beam Method"; and three-point bending strength testing was performed on each ceramic liner according to GB / T 6569 "Test Method for Bending Strength of Fine Ceramics". The results are shown in Table 1 below. Table 1. Performance test results of wear-resistant ceramic liners

[0068] As shown in Table 1, the wear-resistant ceramic liners prepared in Examples 1-3 have significantly better performance than those in Comparative Examples 1-3. The performance of the wear-resistant ceramic liners prepared in Comparative Examples 1-3 is reduced due to the absence of any one of the three components: modified urea-formaldehyde resin microspheres, hafnium boride, or tungsten disilicide.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A wear-resistant ceramic liner, characterized in that: The product, by weight, comprises the following raw materials: 100 parts alumina, 3.8-4.2 parts sintering aid, 5-7 parts aluminum titanate, 3-4 parts modified urea-formaldehyde resin microspheres, 4-6 parts hafnium boride, 1.5-1.7 parts tungsten disilicide, and 0.8-1.0 parts KH-550 silane coupling agent. The sintering aid is a mixture of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide. The preparation method of the modified urea-formaldehyde resin microspheres comprises the following steps: ① preparation of a metal salt-citric acid complex solution; ② preparation of a urea-formaldehyde prepolymer solution; ③ pouring the urea-formaldehyde prepolymer solution into a reaction vessel, adding the metal salt-citric acid complex solution dropwise while stirring at room temperature, adjusting the pH of the system to 5.5, and continuing stirring until complete complexation; ④ preparing a gel solution through a condensation reaction; ⑤ curing and molding the oil phase; ⑥ washing, drying, and sieving to obtain the modified urea-formaldehyde resin microspheres.

2. The wear-resistant ceramic liner according to claim 1, characterized in that: The mass ratio of niobium pentoxide, strontium oxide, lanthanum oxide, and magnesium oxide in the sintering aid is 0.5:1:2:

2.

3. The wear-resistant ceramic liner according to claim 1, characterized in that: The preparation method of the modified urea-formaldehyde resin microspheres includes step ①, the preparation of the metal salt-citric acid complex solution, which is as follows: citric acid and water-soluble phenolic resin are added to deionized water accounting for 35% of the total mass of deionized water and stirred at 40°C and 300 r / min for 15 min. Niobium oxalate is added and stirred for 15 min. Ammonium heptamolybdate tetrahydrate is added and stirred for 10 min. Chromium nitrate is added and stirred for 10 min. Finally, deionized water accounting for 65% of the total mass of deionized water is added and stirred until clear to obtain the metal salt-citric acid complex solution. In step ①, the molar ratio of the metal elements in niobium oxalate, ammonium heptamolybdate tetrahydrate, and chromium nitrate is 3:4:2, and the total metal ion concentration in the deionized water is controlled to be 0.67 mol / L. In step ①, the ratio of the sum of the amounts of molybdenum in niobium oxalate, chromium nitrate, and ammonium heptamolybdate tetrahydrate to the amount of citric acid in the metal salt-citric acid complex solution is 1:1.

4. In step ①, the ratio of the sum of the amounts of molybdenum in niobium oxalate, chromium nitrate, and ammonium heptamolybdate tetrahydrate to the amount of water-soluble phenolic resin in the preparation of the metal salt-citric acid complex solution is 1:1.

8.

4. The wear-resistant ceramic liner according to claim 1, characterized in that: Step ② Preparation of urea-formaldehyde prepolymer solution is as follows: Dissolve urea in deionized water and stir at room temperature until completely dissolved. Then add formaldehyde solution and continue stirring and mixing for 17 minutes to prepare urea-formaldehyde prepolymer solution. The molar ratio of urea to formaldehyde is 1:1.6, the mass concentration of formaldehyde solution is 37%, and the mass ratio of urea to deionized water is 1:0.

92.

5. The wear-resistant ceramic liner according to claim 1, characterized in that: Step ③ is as follows: Pour the urea-formaldehyde prepolymer solution into a reaction vessel and stir at 350 r / min at room temperature. Add the metal salt-citric acid complex solution dropwise at a rate of 5 mL / min for 30 min. Then, add 1 mol / L NaOH solution to adjust the pH of the system to 5.

5. Adjust the stirring speed to 300 r / min and continue stirring for 60 min until the complexation is complete. The volume ratio of the urea-formaldehyde prepolymer solution to the metal salt-citric acid complex solution is 0.83:

1.

6. The wear-resistant ceramic liner according to claim 1, characterized in that: Step ④ describes the preparation of the gel solution via polycondensation reaction as follows: within 15 minutes, the temperature of the reaction system is raised from room temperature to 80°C at a rotation speed of 300 r / min. Then, the rotation speed is adjusted to 250 r / min, and the reaction is continuously stirred at 80°C for 60 minutes. After stirring is stopped, the polycondensation reaction is complete.

7. The wear-resistant ceramic liner according to claim 1, characterized in that: Step ⑤, the oil phase curing and molding process, is as follows: using liquid paraffin as the oil phase, the syringe draws in the gel liquid, removes air bubbles, and fixes it vertically with a 21G needle. The distance between the needle and the liquid paraffin is 4cm, and the dripping speed is controlled at 30 drops / min. The gel liquid is dripped into the liquid paraffin. After the liquid drop is added to the oil, it immediately shrinks into a ball. After the dripping is completed, it is first allowed to stand and cure in the liquid paraffin for 2.5h at a standing curing temperature of 77℃, and then allowed to cool naturally to room temperature.

8. The wear-resistant ceramic liner according to claim 1, characterized in that: The washing, drying, and sieving process described in step ⑥ to prepare modified urea-formaldehyde resin microspheres is as follows: After the microspheres are taken out, they are first washed three times with petroleum ether at 75°C for 10 minutes each time, then washed three times with anhydrous ethanol for 10 minutes each time, and finally washed once with deionized water for 8 minutes. They are then naturally air-dried at 25°C for 20 hours, dried at 41°C for 12 hours, dried at 61°C for 10 hours, and dried at 82°C for 8 hours. Finally, they are graded using standard sieves, and the microspheres that pass through a 14-mesh sieve but are retained between 18-mesh sieves are collected.

9. A method for preparing the wear-resistant ceramic liner according to claim 1, characterized in that: It consists of the following steps: (1) Mix KH-550 silane coupling agent, deionized water and ethanol, add acetic acid to adjust the pH of the system to 4.0, stir and hydrolyze at room temperature for 30-35 min to prepare hydrolysate; (2) Add alumina, aluminum titanate, hafnium boride and sintering aid to a ball mill jar, add hydrolysate and ball mill for 35-40 min, then add modified urea-formaldehyde resin microspheres and continue ball milling for 30-35 min, finally add deionized water and tungsten disilicide and continue ball milling for 25-30 min to prepare a slurry; (3) The slurry was dried in a vacuum drying oven and then ground through a 200-mesh sieve to obtain granulated powder; (4) The granulated powder is filled into the mold and dry-pressed to obtain the green body; (5) Place the blank in a graphite mold, put it into a hot press furnace and evacuate it. First, heat it to 200℃ at a heating rate of 5℃ / min and hold it for 30min. Then, heat it to 600-610℃ at a heating rate of 2℃ / min and hold it for 30min. Then, fill the furnace with argon gas to a pressure of 0.25MPa and heat it to 1100-1105℃ at a heating rate of 5℃ / min. Within 20min, apply axial mechanical pressure to 35MPa. Under the condition of maintaining this pressure, heat it to 1650-1680℃ at a heating rate of 5℃ / min and hold it for 1.5h. After the holding is completed, cool it to room temperature with the furnace under the condition of maintaining a pressure of 35MPa. After demolding, wear-resistant ceramic liner is obtained.

10. The method for preparing the wear-resistant ceramic liner according to claim 9, characterized in that: In step (1), the mass ratio of KH-550 silane coupling agent, ethanol, and deionized water is 1:144:

16. In step (2), alumina, aluminum titanate, hafnium boride and sintering aid are added to a ball mill jar, and hydrolysate is added and ball milled for 35-40 min at a speed of 250 r / min. Then, modified urea-formaldehyde resin microspheres are added and ball milling continues for 30-35 min at a speed of 150 r / min. Finally, deionized water and tungsten disilicide are added and ball milling continues for 25-30 min at a speed of 150 r / min to prepare a slurry. Zirconia balls with a diameter of 1 mm are selected as the grinding medium throughout the ball milling process. In step (2), deionized water is added to adjust and control the solid content of the slurry to 55-60%; In step (3), the vacuum drying temperature is 60℃ and the vacuum drying time is 5.5-6h; In step (4), the pressure for dry pressing is 180 MPa and the time for dry pressing is 15 s.

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