Micro-closed-pore-containing high-thermal-shock-resistance zirconium oxide nozzle material and preparation method thereof

Abstract

The invention relates to the technical field of zirconium oxide refractory materials, in particular to a micro-closed-pore-containing high-thermal-shock-resistance zirconium oxide nozzle material and a preparation method thereof. The preparation method comprises the following steps: 1, uniformly mixing 20-40 parts by mass of partially stable ZrO2 micro powder, 60-80 parts by mass of monoclinic ZrO2 micro powder, 1-8 parts by mass of a stabilizer and 1-15 parts by mass of a nano additive as raw materials according to a ratio to obtain mixed powder; 2, adding 1-3 parts by mass of a binder, uniformly mixing, and carrying out mechanical pressing molding; and 3, curing, drying, sintering for 1-3 hours at the temperature of 1600-1800 DEG C, reducing the temperature to 1400-1600 DEG C, and preserving heat for 4-6 hours. The micro-closed-pore-containing high-thermal-shock-resistance zirconia nozzle material prepared by the method has the characteristics of small pore diameter, high closed porosity, fine grain size and the like, and shows good erosion resistance, scouring resistance and thermal shock resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of zirconia refractory materials, in particular to a micro-closed-pore high-thermal-shock-resistant zirconia nozzle material and a preparation method thereof. Background Art

[0002] In the metallurgical continuous casting process, the tundish nozzle is a key component for controlling the flow rate and direction of molten steel and preventing secondary oxidation. Its performance is directly related to production efficiency and billet quality. Zirconia (ZrO) is widely used in the field of nozzle materials due to its high melting point (approximately 2700°C), good high-temperature chemical stability and corrosion resistance. However, traditional zirconia nozzles are in direct contact with molten steel during operation and are exposed to high-temperature environments for long periods of time. Due to their insufficient resistance to corrosion, erosion, or thermal shock, they are prone to spalling, cracking, and even breakage, leading to nozzle damage. In severe cases, this can cause steel leakage accidents, threatening production safety and increasing maintenance costs.

[0003] Damage to zirconia nozzles mainly comes from thermal shock and erosion by molten steel. Therefore, the material's erosion resistance, erosion resistance, and thermal shock resistance are key factors determining its service life. However, for existing zirconia nozzle materials, it is often difficult to strike a balance between erosion resistance, erosion resistance, and thermal shock resistance. To improve the thermal shock resistance of zirconia, the method of introducing pores is usually used to alleviate thermal stress. However, while the introduction of pores can alleviate thermal stress to a certain extent, it significantly reduces the mechanical strength of the material, thereby weakening its erosion resistance. On the other hand, the pores in conventional porous zirconia materials are mostly visible pores. The open pore structure increases the contact area between the molten steel and the material, thereby exacerbating the spalling of the material and reducing its erosion resistance. In addition, if the pores are unevenly distributed or large in size, stress concentration is easily generated inside the material during thermal shock, thereby promoting the formation and expansion of cracks. Ultimately, this affects the improvement of the material's thermal shock resistance.

[0004] The patented technology of “A micro-closed-pore lightweight zirconia refractory material and its preparation method” (CN 115947597 B) is to mix the raw materials with a certain proportion of water, dry, ball-mill, shape, and sinter to obtain a micro-closed-pore lightweight zirconia refractory material. Although the invention has the characteristics of simple process and low cost, the introduction of water and drying make the production process cumbersome and reduce production efficiency. The micro-closed-pore lightweight zirconia refractory material prepared by the invention has a high closed porosity, which improves the material's corrosion resistance and thermal shock resistance. However, the production process based on pure monoclinic zirconia and stabilized by stabilizers is difficult to ensure the stability of the content of each phase during the thermal shock process, thereby limiting the further improvement of its thermal shock resistance. In addition, the invention has a relatively wide range of control over the zirconia grain size, which is difficult to meet the grain size requirements of zirconia with high thermal shock resistance.

[0005] The patented technology, "A method for manufacturing high-quality zirconia nozzles using magnesium-zirconium eutectic materials and monoclinic zirconia" (CN115231931A), involves ball milling, mixing, screening, drying, forming, and sintering the raw materials to produce high-quality zirconia nozzles. This invention features a simple process, low cost, and high production efficiency. However, the pores in the high-quality zirconia nozzles produced by this invention are mostly visible pores, which increases the contact area between the nozzle and the molten steel, exacerbating the erosion reaction of the molten steel on the nozzle and reducing the service life of the zirconia nozzles.

[0006] The patented technology of "A corrosion-resistant zirconia nozzle brick and its preparation method" (CN108164275A) involves mixing and fine-grinding the raw materials, and then performing preliminary sintering under nitrogen pressure after forming. The sintered blank is crushed and granulated, and then subjected to secondary sintering under nitrogen pressure after forming to finally obtain corrosion-resistant zirconia nozzle bricks. The corrosion-resistant zirconia nozzle bricks produced by this invention have a higher density and a lower porosity, and therefore have higher mechanical strength and good corrosion resistance. However, the production process is complex, the cost is high, and the requirements for production equipment are high. In addition, too low a porosity makes it difficult to alleviate the volume effect caused by the zirconia crystal phase transformation at high temperature, as well as the stress concentration caused by thermal shock conditions. Therefore, the corrosion-resistant zirconia nozzle bricks produced by this invention have insufficient thermal shock resistance.

[0007] The patented technology of "A method for preparing high-temperature thermal shock-resistant zirconia nozzle bricks" (CN105732028A) involves ball-milling, mixing, and roasting the raw materials before soaking them in a dilute acid solution. The soaked powder is then mixed with a stabilizer and a binder, molded, and sintered to obtain high-temperature thermal shock-resistant zirconia nozzle bricks. The high-temperature thermal shock-resistant zirconia nozzle bricks produced by this invention have strong mechanical properties and good corrosion resistance, but the low porosity is not enough to effectively improve the thermal shock stability of the product. In addition, this invention also has the disadvantages of complex process, high cost, and low production efficiency.

[0008] The patented technology, "A Zirconia Crucible for Precision Casting and Its Heat Treatment Method" (CN109516802B), combines monoclinic and stabilized zirconia of varying particle sizes in a designed ratio. The crucible is heat-treated using a stepwise sintering process from high to low temperatures, resulting in a zirconia crucible with a low coefficient of thermal expansion. While the zirconia crucible produced by this invention has a low coefficient of thermal expansion, the low sintering temperature makes it difficult to achieve a high density, thereby reducing the mechanical strength of the zirconia. Furthermore, excessive pores increase the contact area between the material's interior and the outside world, making it difficult to maintain the material's corrosion resistance and making it susceptible to stress concentration in thermal shock environments, thereby reducing the zirconia's thermal shock resistance.

[0009] Based on this, it is urgent to develop a new type of zirconia nozzle material. By coordinating the relationship between the material's anti-erosion, anti-scouring and thermal shock resistance, while optimizing the material's anti-erosion and anti-scouring properties, the material's thermal shock resistance can be further improved, thereby meeting the continuous casting process's stringent requirements for long life and high reliability of nozzle materials. Summary of the Invention

[0010] The present invention aims to address the aforementioned shortcomings of the prior art by providing a micro-closed-pore, highly thermal-shock-resistant zirconia nozzle material and a method for preparing the same. The micro-closed-pore, highly thermal-shock-resistant zirconia nozzle material prepared by this method exhibits small pore diameters, high closed-pore porosity, and fine grain size, demonstrating excellent resistance to erosion, scour, and thermal shock.

[0011] The first object of the present invention is to provide a method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia, comprising the following steps:

[0012] Step 1: Using 20-40 parts by mass of partially stabilized ZrO2 fine powder, 60-80 parts by mass of monoclinic ZrO2 fine powder, 1-8 parts by mass of a stabilizer and 1-15 parts by mass of a nano additive as raw materials, mixing them according to the proportions to obtain a mixed powder;

[0013] Step 2: Add 1 to 3 parts by mass of a binder, mix well, and press into shape;

[0014] Step 3: solidify, dry, sinter at 1600-1800℃ for 1-3 hours, then reduce the temperature to 1400-1600℃ and keep it for 4-6 hours to obtain a micro-closed-pore high thermal shock resistant zirconia nozzle material;

[0015] The partially stabilized ZrO2 fine powder comprises at least one of fused magnesium partially stabilized ZrO2, fused yttrium partially stabilized ZrO2, and fused calcium partially stabilized ZrO2, wherein the ZrO2 content of the partially stabilized ZrO2 fine powder is greater than 93wt%, and the particle size D50 is 20 to 100μm;

[0016] The monoclinic ZrO2 powder has a particle size D50 of 1 to 20 μm;

[0017] The stabilizer includes at least one of Y2(CO3)3, MgCO3, Ce(CO3)2, Y2O3, MgO, CeO2 and CaO2, and the particle size D50 of the stabilizer is 1 to 15 μm;

[0018] The nano additive comprises at least one of nano magnesium oxide, nano aluminum oxide, nano zirconium oxide and nano yttrium oxide, and the particle size D50 of the nano additive is 20-90 nm.

[0019] Furthermore, the partially stabilized ZrO2 fine powder includes at least one of fused magnesium partially stabilized ZrO2, fused yttrium partially stabilized ZrO2, and fused calcium partially stabilized ZrO2.

[0020] Furthermore, the ZrO2 content of the partially stabilized ZrO2 fine powder is greater than 93wt%.

[0021] Furthermore, the monoclinic ZrO2 powder is at least one of fused ZrO2 and chemical ZrO2.

[0022] Furthermore, the ZrO2 content of the monoclinic ZrO2 powder is greater than 99wt%.

[0023] Furthermore, the binder is polyethylene glycol or polyvinyl alcohol.

[0024] Furthermore, the pressure of the machine compression molding is 50-150 MPa.

[0025] Furthermore, the sintering temperature has a heating rate of 1 to 10° C. / min and a cooling rate of 5 to 10° C. / min.

[0026] Furthermore, the stabilizer is 1 to 4 parts by mass.

[0027] The first object of the present invention is to provide a micro-closed-pore high thermal shock resistant zirconia nozzle material prepared by the above-mentioned preparation method.

[0028] Due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art:

[0029] In order to coordinate the relationship between the erosion resistance, scour resistance and thermal shock resistance of zirconia, the present invention regulates the pore structure, phase composition and grain size of the zirconia material, thereby optimizing the erosion resistance and scour resistance of the material while further improving the thermal shock resistance of the material.

[0030] Improved erosion resistance: On the one hand, this invention optimizes the particle size distribution of the raw materials, reducing the material's porosity and increasing its density during the sintering process. On the other hand, the introduction of nanoparticles accelerates the diffusion rate at grain boundaries, enabling material diffusion and particle merging to complete in a shorter time. Some gas is trapped within the grains before it diffuses to the material surface, forming closed pores. The higher density and closed pores reduce the contact area between the material's interior and the outside world, effectively improving the material's erosion resistance.

[0031] Improved erosion resistance: On the one hand, nanoparticles, due to their small size, can fill the gaps between larger particles and act as "bridges" during the sintering process, thereby increasing the material's density and strengthening the bond strength between grain boundaries, ultimately enhancing the material's mechanical properties. On the other hand, the zirconia grain size is controlled through a heat treatment process with step-down sintering. During the high-temperature stage, the material's densification process primarily occurs through grain boundary diffusion and volume diffusion, both of which require less energy than grain growth (grain boundary migration). Therefore, during the initial sintering phase, the rate of densification is much higher than the rate of grain growth, resulting in rapid formation of the grain boundary network but limited grain size growth. At low temperatures, the energy required for grain growth (grain boundary migration) is insufficient, significantly reducing the grain boundary migration rate and slowing or stagnating grain growth. Furthermore, due to insufficient energy supply, the rate at which larger grains absorb smaller grains through the dissolution-precipitation mechanism is significantly reduced. As a result, the grain size distribution becomes finer and more uniform. Fine grains can increase the grain boundary density of the material, improve the yield strength of the material, and thus hinder dislocation movement and crack propagation within the material, ultimately improving the material's mechanical strength. In addition, small and uniform grains tend to have a denser and smoother surface, which can reduce microcracks and wear caused by scouring, thereby improving the material's anti-scouring performance.

[0032] Improvement of thermal shock resistance: In terms of structure, the present invention adopts the particle stacking method to introduce an appropriate amount of pores into the material. The presence of pores can, on the one hand, alleviate the volume effect caused by the phase transformation of zirconia at high temperature, and on the other hand, can alleviate the stress concentration caused by excessive temperature changes in the local area, and reduce the conduction of stress, thereby improving the thermal shock resistance of the material and avoiding the generation and expansion of cracks in the material due to excessive volume effect and stress concentration.

[0033] In terms of phase composition, the present invention precisely controls the phase composition of zirconia (monoclinic, tetragonal and cubic zirconia) by adding a composite stabilizer. On the one hand, the composite stabilizer can achieve a certain degree of dynamic balance between the lattice expansion of zirconia grains caused by thermal stress and the volume effect produced by the phase transition between different crystal forms at high temperatures, thereby reducing the thermal expansion coefficient of zirconia at high temperatures and improving the thermal shock resistance of zirconia. On the other hand, the combined action of multiple stabilizers can enhance the grain boundary strength of tetragonal and cubic zirconia and improve its thermal stability, thereby slowing down the desolvation of stabilizers in tetragonal and cubic zirconia under thermal shock conditions, making the phase composition of the material before and after thermal shock tend to be stable, thereby improving its thermal shock resistance. In terms of grain size, small and uniform grains can shorten the heat diffusion path, reduce the temperature gradient, and reduce the anisotropy of the grains, so that the material can evenly disperse the thermal stress during the thermal shock process, avoiding cracking and damage caused by stress concentration caused by excessive grain size differences, thereby improving the thermal shock resistance of the material.

[0034] The test shows that the micro-closed pore high thermal shock resistant zirconia nozzle material prepared by the present invention has a volume density of 4.8-5.3 g / cm 3 , the apparent porosity is 1-10%, the closed porosity is 5-9%, the average pore diameter is 3-12μm, the average grain size is 4-10μm, and the number of thermal shock cycles is 9-18 times.

[0035] In summary, the method for preparing the micro-closed-pore, highly thermal-shock-resistant zirconia nozzle material prepared by the present invention features a simple process, low cost, high production efficiency, and suitability for industrial production. The micro-closed-pore, highly thermal-shock-resistant zirconia nozzle material prepared by the present invention exhibits small pore diameter, high closed-pore porosity, and fine grain size, exhibiting excellent resistance to erosion, scour, and thermal shock. It is suitable for the production of products such as tundish nozzles, refractory crucibles, and high-temperature furnace linings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a secondary electron image of the plane pores of the micro-closed-pore high thermal shock resistant zirconia nozzle material prepared in Example 1;

[0037] Figure 2 This is a secondary electron image of the plane pores of the micro-closed-pore high thermal shock resistant zirconia nozzle material prepared in Example 3;

[0038] Figure 3 This is a secondary electron image of the fracture of the micro-closed-pore high thermal shock resistant zirconia nozzle material prepared in Example 1 after thermal shock;

[0039] Figure 4 This is a secondary electron image of the fracture of the micro-closed-pore high thermal shock resistant zirconia nozzle material prepared in Example 4 after thermal shock. DETAILED DESCRIPTION

[0040] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0041] To avoid repetition, the raw materials and process parameters involved in this specific embodiment are first described as follows, and will not be repeated in the examples:

[0042] Step 1: Using 20-40 parts by mass of partially stabilized ZrO2 fine powder, 60-80 parts by mass of monoclinic ZrO2 fine powder, 1-8 parts by mass of a stabilizer and 1-15 parts by mass of a nano additive as raw materials, mixing them according to the proportions to obtain a mixed powder;

[0043] Step 2: Add 1 to 3 parts by mass of a binder, mix well, and press into shape;

[0044] Step 3: solidify and dry under high temperature conditions, sinter at 1600-1800°C for 1-3 hours, then reduce the temperature to 1400-1600°C and keep warm for 4-6 hours to obtain a micro-closed-pore high thermal shock resistant zirconia nozzle material;

[0045] The partially stabilized ZrO2 fine powder is one or more of fused magnesium partially stabilized ZrO2, fused yttrium partially stabilized ZrO2, and fused calcium partially stabilized ZrO2, wherein the ZrO2 content of the partially stabilized ZrO2 fine powder is greater than 93wt%, and the particle size D50 is 20 to 100μm;

[0046] The monoclinic ZrO2 fine powder is at least one of fused ZrO2 and chemical ZrO2, the ZrO2 content of the monoclinic ZrO2 fine powder is greater than 99wt%, and the particle size D50 is 1 to 20μm;

[0047] The stabilizer is at least one of Y2(CO3)3, MgCO3, Ce(CO3)2, Y2O3, MgO, CeO2 and CaO2, and the particle size D50 of the stabilizer is 1 to 15 μm;

[0048] The nano additive is one or more of nano magnesium oxide, nano aluminum oxide, nano zirconium oxide and nano yttrium oxide, and the particle size D50 of the nano additive is 20 to 90 nm.

[0049] The binder is polyethylene glycol or polyvinyl alcohol.

[0050] The pressure of the machine pressing is 50-150 MPa.

[0051] The heating rate of the sintering temperature is 1-10°C / min, and the cooling rate is 5-10°C / min.

[0052] Example 1

[0053] 30 parts by mass of partially stabilized ZrO2 fine powder, 70 parts by mass of monoclinic ZrO2 fine powder, 4 parts by mass of a composite stabilizer (Y2O3, CeO2) and 15 parts by mass of a nano-additive are used as raw materials, mixed according to a proportion to obtain a mixed powder, then 2 parts by mass of a binder are added, mixed evenly, machine-pressed, and then cured and dried under high temperature conditions. After sintering at 1800°C for 3 hours, the temperature is lowered to 1500°C and kept at this temperature for 6 hours to obtain a micro-closed-pore high thermal shock resistance zirconia nozzle material;

[0054] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 5.1 g / cm 3 , the apparent porosity is 2%, the closed porosity is 9%, the average pore diameter is 4μm, the average grain size is 5μm, and the number of thermal shock cycles is 18 times.

[0055] Example 2

[0056] 8 parts by mass of the composite stabilizer was used, and the other aspects were the same as in Example 1 to prepare a nozzle material containing micro-closed pores and high thermal shock resistance of zirconia;

[0057] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 5.3 g / cm 3 , the apparent porosity is 1%, the closed porosity is 7%, the average pore diameter is 3μm, the average grain size is 5μm, and the number of thermal shock cycles is 9 times.

[0058] Example 2 is a comparison of the stabilizer content with Example 1. The number of thermal shock cycles decreases because too much stabilizer will lead to excessive content of tetragonal and cubic phases, which will destroy the stability of the volume effect at high temperature.

[0059] Example 3

[0060] 40 parts by mass of partially stabilized ZrO2 fine powder and 60 parts by mass of monoclinic ZrO2 fine powder were used, and the other ingredients were the same as those in Example 1 to prepare a nozzle material containing micro-closed pores and high thermal shock resistance of zirconia.

[0061] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 4.8 g / cm 3 , the apparent porosity is 10%, the closed porosity is 5%, the average pore diameter is 12μm, the average grain size is 10μm, and the number of thermal shock cycles is 13 times.

[0062] Example 3 is a comparison of the particle grading with Example 1. The greater the proportion of large particles, the more difficult it is to close the pores, the closed pore content decreases, the apparent pore content increases, the grain size and pore diameter increase, resulting in reduced thermal shock resistance.

[0063] Example 4

[0064] 4 parts by mass of stabilizer Y2O3 were used, and other aspects were the same as in Example 1 to prepare a nozzle material containing micro-closed pores and high thermal shock resistance zirconia;

[0065] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 5.0 g / cm 3 , the apparent porosity is 4%, the closed porosity is 8%, the average pore diameter is 6μm, the average grain size is 6μm, and the number of thermal shock cycles is 15 times.

[0066] Example 4 is a comparison of Example 1 with respect to the type of stabilizer. With other factors remaining unchanged, the composite stabilizer has multiple effects on the stability of zirconia. Therefore, compared with a single stabilizer, the composite stabilizer has a more significant improvement in the thermal shock resistance of zirconia.

[0067] Example 5

[0068] After sintering at 1600°C for 3 hours, the temperature was lowered to 1500°C and kept for 6 hours. Other processes were the same as in Example 1 to obtain a nozzle material containing micro-closed pores and high thermal shock resistance of zirconia.

[0069] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 5.0 g / cm 3 , the apparent porosity is 6%, the closed porosity is 5%, the average pore diameter is 9μm, the average grain size is 4μm, and the number of thermal shock cycles is 11 times.

[0070] Example 5 is a comparison of the sintering temperature with Example 1. The temperature in the high-temperature stage is low, and the grain growth is slow, which cannot close many pores. Therefore, the grain size of the material is small, the apparent porosity is high, and the pore diameter is large, which reduces the thermal shock resistance of the material.

[0071] Example 6

[0072] 7 parts by mass of the nano additive was used, and the other aspects were the same as in Example 1 to prepare a nozzle material containing micro-closed pores and high thermal shock resistance zirconia;

[0073] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 5.0 g / cm 3 , the apparent porosity is 4%, the closed porosity is 9%, the average pore diameter is 5μm, the average grain size is 6μm, and the number of thermal shock cycles is 15 times.

[0074] Example 6 compares the nanoadditive content with Example 1. Reducing the nanoadditive content reduces the number of "bridges" between particles, thus reducing the inhibitory effect on grain growth. Consequently, the apparent pore content increases, the grain size increases, and the material's density decreases. Since the change in pore size is minimal, the impact on the material's thermal shock resistance is limited.

[0075] Example 7

[0076] 30 parts by mass of partially stabilized ZrO2 fine powder, 70 parts by mass of monoclinic ZrO2 fine powder, 2 parts by mass of a composite stabilizer (Y2O3, CeO2) and 8 parts by mass of a nano-additive are used as raw materials, mixed according to a proportion to obtain a mixed powder, and then 1 part by mass of a binder is added, mixed evenly, pressed into shape, and then cured and dried under high temperature conditions. After sintering at 1700°C for 1 hour, the temperature is lowered to 1500°C and kept at this temperature for 4 hours to obtain a micro-closed-pore high thermal shock resistance zirconia nozzle material;

[0077] The micro-closed pore high thermal shock resistant zirconia nozzle material prepared in this embodiment has a volume density of 5.1 g / cm 3 , the apparent porosity is 3%, the closed porosity is 9%, the average pore diameter is 5μm, the average grain size is 6μm, and the number of thermal shock cycles is 13 times.

[0078] contrast Figure 1 、 Figure 2 It can be seen that the micro-closed-pore, high-thermal-shock-resistant zirconia nozzle material prepared in Example 1 has smaller pores, more regular shapes, and a more uniform distribution. The micro-closed-pore, high-thermal-shock-resistant zirconia nozzle material prepared in Example 3 has larger pores, more complex shapes, and a more random distribution. Some pores are interconnected to form interconnected pores. This is because, compared to Example 1, Example 3 contains more large particles, which increases the porosity and pore size. The lower content of nanoparticles makes it difficult to effectively fill the gaps between the particles, thereby increasing the material's density.

[0079] contrast Figure 3 、 Figure 4 It can be seen that compared to Example 4, the micro-closed-pore, highly thermal shock-resistant zirconia nozzle material prepared in Example 1 effectively slows down the desolvation of the stabilizer from the tetragonal and cubic zirconia phases after a single thermal shock cycle. This is because, under the condition of the same stabilizer content, the combined effect of multiple stabilizers can enhance the stability of the tetragonal and cubic zirconia crystal structures, improve their thermal stability, thereby increasing the material's phase retention rate in a thermal shock environment, and further improving the material's thermal shock resistance.

[0080] In summary, the micro-closed-pore high thermal shock resistant zirconia nozzle material prepared by the present invention has the characteristics of small pore diameter, high closed-pore porosity, and fine grain size, and exhibits good corrosion resistance, erosion resistance and thermal shock resistance.

[0081] Any matters not mentioned above shall be subject to the existing technology.

[0082] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them in similar ways, but they will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia, characterized in that: The steps include: Step 1: Using 20-40 parts by mass of partially stabilized ZrO2 fine powder, 60-80 parts by mass of monoclinic ZrO2 fine powder, 1-8 parts by mass of a stabilizer and 1-15 parts by mass of a nano additive as raw materials, mixing them according to the proportions to obtain a mixed powder; Step 2: Add 1 to 3 parts by mass of a binder, mix well, and press into shape; Step 3: solidify, dry, sinter at 1600-1800℃ for 1-3 hours, then reduce the temperature to 1400-1600℃ and keep it for 4-6 hours to obtain a micro-closed-pore high thermal shock resistant zirconia nozzle material; The partially stabilized ZrO2 fine powder comprises at least one of fused magnesium partially stabilized ZrO2, fused yttrium partially stabilized ZrO2, and fused calcium partially stabilized ZrO2, wherein the ZrO2 content of the partially stabilized ZrO2 fine powder is greater than 93wt%, and the particle size D50 is 20 to 100μm; The monoclinic ZrO2 powder has a particle size D50 of 1 to 20 μm; The stabilizer includes at least one of Y2(CO3)3, MgCO3, Ce(CO3)2, Y2O3, MgO, CeO2 and CaO2, and the particle size D50 of the stabilizer is 1 to 15 μm; The nano additive comprises at least one of nano magnesium oxide, nano aluminum oxide, nano zirconium oxide and nano yttrium oxide, and the particle size D50 of the nano additive is 20-90 nm.

2. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The partially stabilized ZrO2 fine powder includes at least one of fused magnesium partially stabilized ZrO2, fused yttrium partially stabilized ZrO2, and fused calcium partially stabilized ZrO2.

3. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The ZrO2 content of the partially stabilized ZrO2 fine powder is greater than 93 wt%.

4. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The monoclinic ZrO2 powder is at least one of fused ZrO2 and chemical ZrO2.

5. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The ZrO2 content of the monoclinic ZrO2 fine powder is greater than 99 wt%.

6. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The binder is polyethylene glycol or polyvinyl alcohol.

7. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The pressure of the machine pressing is 50-150 MPa.

8. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The heating rate of the sintering temperature is 1-10°C / min, and the cooling rate is 5-10°C / min.

9. The method for preparing a nozzle material containing micro-closed pores and high thermal shock resistance zirconia according to claim 1, characterized in that: The stabilizer is 1 to 4 parts by mass.

10. A nozzle material containing micro-closed pores and high thermal shock resistance of zirconia prepared by the preparation method according to any one of claims 1 to 9.

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