Multi-element oxide ceramic coating refractory brick material containing reinforcement phase and preparation method thereof

Abstract

The invention discloses a reinforcement phase-containing multi-element oxide ceramic coating refractory brick material and a preparation method thereof, and belongs to the field of ceramic material preparation. The method comprises the following steps: mixing powder raw materials including coated and modified silicon carbide, Al2O3, a CMSP mixed oxide and a dispersing agent with a solvent to obtain slurry; the surface of a refractory brick matrix subjected to sand blasting roughening is coated with the slurry, and then vacuum sintering and annealing treatment are performed to obtain the refractory brick. The composite material obtained by the method disclosed by the invention has the advantages of high density, high hardness, tight combination of a matrix and a coating, good high-temperature slag corrosion resistance and the like, and can meet the long-acting protection requirement of the refractory brick in a harsh high-temperature environment.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of refractory brick materials of reinforced phase-containing multi-component oxide ceramic coating and its preparation method, belong to the field of ceramic material preparation. BACKGROUND

[0002] As the key protective material of high-temperature industrial kiln, refractory bricks are widely used in cement rotary kiln, steel blast furnace hot blast furnace, glass melting furnace pool wall and waste incinerator lining, etc. Its service performance is directly related to the operation safety, production efficiency and maintenance cycle of the kiln. Although the commonly used high alumina bricks and other refractory materials have basic high-temperature resistance, they still face serious problems of high-temperature slag erosion and high-temperature oxidation wear during long-term continuous use. Molten slag can easily penetrate into the brick body and react with it, forming a low-melting-point phase, which leads to loose structure and surface spalling. At the same time, high-temperature oxidation will cause the strength of the brick body to decrease, and the material damage will be further intensified under the combined influence of airflow scouring and mechanical wear.

[0003] To improve the service life of refractory bricks, the existing technology mainly uses the method of preparing protective coating on the surface of the refractory bricks, including spraying method and traditional slurry sintering method. However, these methods have obvious limitations. The spraying method has insufficient coverage for deep holes, grooves and complex inner walls, and often requires preheating of the substrate to control thermal stress. The traditional slurry sintering method is prone to low bonding strength and coating falling off due to the significant difference in thermal expansion coefficient between the coating and the refractory brick substrate. At the same time, the coating has poor compactness and is difficult to resist molten slag penetration and high-temperature oxidation for a long time, resulting in unstable protection effect.

[0004] Therefore, the existing surface coating technology cannot meet the long-term protection needs of refractory bricks in severe high-temperature environments, and a new coating preparation method needs to be developed to improve the bonding performance of the coating and the refractory brick substrate, increase the compactness and erosion resistance, and thus achieve more durable and reliable high-temperature protection for refractory bricks. SUMMARY

[0005] In view of the problems existing in the prior art, the first object of the present application is to provide a refractory brick material with reinforced phase-containing multi-component oxide ceramic coating, which has the advantages of high compactness, high hardness, tight bonding between substrate and coating, and good high-temperature slag erosion resistance, etc., and can meet the long-term protection needs of refractory bricks in severe high-temperature environments.

[0006] The second object of the present application is to provide a preparation method of refractory brick material with reinforced phase-containing multi-component oxide ceramic coating, which has simple preparation process. The method constructs a continuous and dense interface phase by using multi-component oxide and aluminum oxide, significantly improves the interface bonding strength, compactness and high-temperature slag erosion resistance of the coating, has high raw material utilization rate, does not need complex mold, and can meet the surface protection needs of complex shape refractory bricks such as arc bricks and special-shaped bricks.

[0007] In order to achieve the above technical purposes, the application provides a preparation method of a refractory brick material with a reinforced multi-element oxide ceramic coating, which comprises the following steps: mixing powder raw materials including coated modified silicon carbide, Al2O3, CMSP mixed oxide and dispersant and a solvent to obtain a slurry; coating the slurry on the surface of a sandblasted refractory brick substrate, and then performing vacuum sintering and annealing treatment, thereby obtaining the refractory brick material; the CMSP mixed oxide is composed of CaO, MgO, SiO2 and PbO in a mass ratio of (6-8):(6-8):(7-9):(1-2); and the mass ratio of the CMSP mixed oxide to Al2O3 is (21-25):(52.5-105).

[0008] The silicon carbide reinforcing phase in the ceramic coating is distributed in the oxide matrix composed of Al2O3 and CMSP.

[0009] The difference between the thermal expansion of the main flow refractory brick substrate and the ceramic coating is 6-8*10 -6 / ℃, which is a huge difference, so that the traditional ceramic coating is difficult to realize tight bonding with the refractory brick substrate, and the refractory brick substrate has a unique ultra-high temperature application scene, so the density of the coating is required to be very high, otherwise the high-temperature slag resistance performance will be reduced, thereby the refractory brick cannot meet the long-term protection demand in a severe high-temperature environment. The key to significantly improving the high-temperature slag erosion resistance performance of the refractory brick and the interfacial bonding strength of the coating lies in the use of Al2O3 and CMSP to form an oxide matrix and the use of coated modified silicon carbide as a reinforcing phase.

[0010] Specifically, the application uses Al2O3 and CMSP mixed oxide with a specific composition as a matrix material, and introduces coated modified silicon carbide as a reinforcing phase, thereby constructing a uniformly dispersed multi-phase composite structure in the microstructure. First, CaO, MgO and SiO2 in CMSP react with Al2O3 to form a CaO-MgO-Al2O3-SiO2 quaternary continuous glass phase, which has low viscosity and good fluidity, can fully fill the gap between SiC particles, form a dense protective layer, and adjust the thermal expansion coefficient of the coating, so that the difference between the thermal expansion of the refractory brick substrate and the coating is significantly reduced to a compatible range, thereby effectively relieving the interfacial stress caused by thermal mismatch. Al2O3 and SiO2 cannot form a continuous glass phase, and the structure is loose, which is not suitable for the special environment of the refractory brick. Second, CaO in CMSP can react with Al2O3 and SiO2 at high temperature to form a calcium feldspar phase, which can effectively block the penetration of Ca 2+ 、Mg 2+The diffusion to the substrate significantly improves the slag erosion resistance of the coating; at the same time, CaO and MgO can further reduce the eutectic temperature of the aluminosilicate system, promote the formation of Al 3+ In the liquid phase, dissolution and diffusion are realized, and sufficient densification at a lower temperature is achieved. In addition, after the modification of silicon carbide by coating, the dispersibility and particle size uniformity of SiC particles in the ceramic slurry are significantly improved, not only completely inhibiting the agglomeration of micron-sized SiC powder but also promoting the early formation of the aluminosilicate liquid phase, thereby improving the high-temperature slag resistance of the coating. Moreover, after sandblasting and roughening, the roughness of the refractory brick can be further increased, which is beneficial to the subsequent close bonding between the coating and the substrate. The vacuum sintering process realizes the formation and transformation of each phase, thereby densifying the coating structure. The subsequent annealing treatment eliminates the internal stress of the refractory brick substrate and the coating and stabilizes the crystal phase composition. This synergistic effect enables the ceramic coating to have excellent slag penetration and erosion resistance at ultra-high temperatures, and at the same time, forms a firm chemical bond and mechanical interlocking with the refractory brick substrate, thereby realizing long-term protection in severe environments.

[0011] It is found that the mass ratio of CMSP mixed oxide to Al2O3 has an important influence on the overall protective performance of the coating. If the CMSP mixed oxide is less, it will lead to sintering difficulty of the coating, inability to form a continuous quaternary glass phase to fill the interstitial gap between the particles at a reduced sintering temperature, increased porosity of the coating, and even loose structure. When the mass of Al2O3 is too low, it will lead to a significant decrease in the interfacial bonding strength of the coating and the substrate and difficulty in generating a calcium feldspar phase, and the slag erosion and oxidation resistance of the coating will be greatly reduced.

[0012] Further preferably, the CMSP mixed oxide comprises CaO, MgO, SiO2 and PbO in a mass ratio of (7-8):(6-8):(7-8):1; more preferably, the CMSP mixed oxide comprises CaO, MgO, SiO2 and PbO in a mass ratio of 8:6:7:1.

[0013] Further preferably, the mass ratio of the CMSP mixed oxide to Al2O3 is (21-25):(60-70); more preferably, the mass ratio of the CMSP mixed oxide to Al2O3 is 21:70.

[0014] As a preferred scheme, the mass ratio of the coated and modified silicon carbide to Al2O3 is (5-15):70.

[0015] As a preferred scheme, the coated and modified silicon carbide is obtained by sequentially subjecting the silicon carbide powder after acid pickling to spheroidization treatment, silane coupling agent grafting treatment and PEI synchronous grafting and coating treatment.

[0016] The silicon carbide prepared by the method has a particle size of 2-4 microns in the final coating.

[0017] As a preferred solution, the spheroidization treatment is performed by immersing the silicon carbide powder in HF, pre-oxidizing the silicon carbide powder in air at 780-900°C for 2-4 hours, and then performing HF acid washing and drying treatment. The heat preservation in air during the spheroidization treatment is beneficial to the preferential oxidation of silicon carbide into silicon dioxide at sharp locations on the surface of the silicon carbide, and then the silicon dioxide is removed by HF acid, so that silicon carbide powder with higher sphericity can be obtained. Further, the pre-oxidation treatment and the acid washing are repeated 2-4 times.

[0018] As a preferred solution, the silane coupling agent used in the silane coupling agent grafting treatment is composed of KH792 and KH560. In the combination of the two silane coupling agents used in the application, the silane chains of KH792 and KH560 and the amino chains of polyethyleneimine (PEI) are combined by hydrogen bonds to form a double coating layer to completely inhibit the agglomeration of micron-sized SiC powder, and the epoxy groups in KH560 can also form strong chemical bonds with the amino groups of PEI, further improving the dispersion stability.

[0019] As a preferred solution, the conditions of the silane coupling agent grafting treatment are as follows: the silane coupling agent is composed of KH792 and KH560 in a mass ratio of (1-4):(1-3), the temperature is 50-65°C, the time is 2-6 hours, and ultrasonic assistance is used, and the amount of the silane coupling agent is 5-15 wt% of the total amount of the silane coupling agent, the silicon carbide powder after spheroidization treatment, and water. Further preferably, the mass ratio of KH792 to KH560 is (3-4):(1-2).

[0020] As a preferred solution, the conditions of the PEI synchronous grafting coating treatment are as follows: the silicon carbide powder after silane coupling agent grafting treatment is immersed in a polyethyleneimine-containing aqueous solution with a pH of 3-4 for 1-3 hours, the concentration of polyethyleneimine in the polyethyleneimine-containing aqueous solution is 6-8 wt%, and the amount of nano-SiO2 is 5-20 wt% of the amount of the silicon carbide powder after silane coupling agent grafting treatment. By adding a small amount of nano-SiO2 during the coating treatment, the dispersion of the powder can be further improved, the strong bond between the surface of the SiO2 and the PEI and the silicon carbide can be formed by using the silicon hydroxyl groups on the surface of the SiO2, the adhesion of the coating layer can be improved, and the uniformity of the particle size of the SiC particles can be improved.

[0021] Further, the particle size of the nano-SiO2 is 20-50 nm.

[0022] As a preferred solution, the spheroidization treatment further includes acid cleaning and impurity removal treatment.

[0023] Furthermore, the acid pickling and impurity removal process is as follows: the silicon carbide powder is immersed in hydrochloric acid, and ultrasonic operation is performed every 15-20 minutes, followed by filtration and washing with water several times to remove surface impurities such as Ca. 2+ Mg 2+ Fe 3+ wait.

[0024] As a preferred embodiment, the dispersant is composed of TMAH and citric acid in a mass ratio of (3~5):(1~2). By adding a small amount of citric acid to TMAH, this invention utilizes citric acid as an anionic dispersant, which can further improve the dispersion stability of the slurry, maintain the pH of the system within a suitable range, reduce particle flocculation caused by pH fluctuations, and improve coating uniformity.

[0025] As a preferred embodiment, the solvent includes ethanol and ethylene glycol. By employing a mixed solvent, this invention can control the drying process and slow down the drying rate while ensuring the solubility of each material, thus preventing shrinkage cracks and crazing caused by rapid water loss in the coating.

[0026] As a preferred embodiment, the coating method is a combination of dip coating and brush coating, and the thickness of the coating after sintering is 95~105μm by controlling the amount of slurry. Since refractory bricks themselves have a certain porous structure, and the roughness is further improved by sandblasting, experiments have shown that using dip coating first can fill the internal pores of the refractory bricks with slurry, and then using brush coating for surface sealing can further improve the overall density of the refractory bricks.

[0027] Furthermore, the dipping speed is 5~10 mm / s, and the dwell time is 5~10 s.

[0028] As a preferred embodiment, the vacuum sintering procedure is as follows: first, heat to 700~800℃ and hold for 30~50 min to remove residual solvent and organic matter and avoid bubbling; then heat to 1200~1300℃ and hold for 20~40 min to form a continuous liquid phase; then heat to 1400~1500℃ and hold for 1~2 h; then cool to 800~900℃ and cool with the furnace, with a vacuum degree of 0.5~1 MPa.

[0029] As a preferred embodiment, the annealing conditions are: holding at 1000~1100℃ for 1~2 hours, then cooling to 500~600℃ and then cooling with the furnace. For refractory brick materials, high-temperature annealing is an essential step in the present invention. The residual stress generated during sintering due to the difference in thermal expansion and phase transformation between the coating and the refractory brick matrix can be significantly reduced after high-temperature annealing, preventing cracking caused by stress concentration during subsequent high-temperature service. Simultaneously, the stable phase composition at high temperatures can be utilized to enhance the stability of the interfacial bonding strength. If the annealing temperature is too low, the risk of cracking during subsequent high-temperature service of the coating will significantly increase, and the protective performance and interfacial bonding strength will decrease.

[0030] As a preferred embodiment, the surface roughness of the refractory brick matrix after sandblasting is above 4.5 μm. Further, the sandblasting roughening is performed using 80-100 mesh Al2O3 sand particles, with a sandblasting time of 30-60 s and a pressure of 0.4-0.8 MPa.

[0031] This invention also provides a refractory brick material with a multi-component oxide ceramic coating containing a reinforcing phase, obtained by the above-described preparation method. The refractory brick material prepared by this invention has a coating density of up to 98.7%, an interfacial bonding strength ≥35MPa, and a mass loss of only 0.005g due to slag erosion at 1400℃, which can meet the long-term protection requirements under harsh high-temperature environments.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention uses an oxide composed of Al2O3 and CMSP as a matrix on the surface of refractory brick material and a coating prepared by synergistic coating modification of silicon carbide. This significantly reduces the thermal expansion difference between the refractory brick matrix and the ceramic coating, forming a tight interface bond. At the same time, the quaternary continuous glass phase and anorthite phase in the coating improve the density, hardness and high temperature resistance to slag erosion of the composite material, which can meet the long-term protection requirements in harsh high temperature environments.

[0034] (2) By adding a small amount of nano-sized SiO2 during the coating process, the present invention can not only further improve the dispersibility of the powder, but also utilize the silanol groups on its surface to form a strong bond on the PEI and silicon carbide surfaces, thereby improving the adhesion of the coating layer and improving the particle size uniformity of SiC particles.

[0035] (3) The present invention adopts a combination of sandblasting roughening pretreatment and high-temperature annealing posttreatment for refractory brick substrate, which can significantly improve the interfacial bonding strength and stability between refractory brick substrate and coating, and improve the protective performance of coating during subsequent high-temperature service.

[0036] (4) The present invention is uniformly coated on the surface of refractory bricks with complex shapes by combining dip coating and brush coating. It does not require complex molds and can meet the surface protection requirements of refractory bricks with special shapes. Moreover, the raw material utilization rate during the slurry coating process is >90%, and the unsintered slurry can be recycled or recoated, reducing production costs and making it suitable for industrial mass production. Attached Figure Description

[0037] Figure 1 This is a surface SEM image of the ceramic coating prepared in Example 1 of the present invention.

[0038] Figure 2 This is a surface SEM image of the ceramic coating prepared in Example 2 of the present invention.

[0039] Figure 3 This describes the effect of the total amount of compound silane coupling agent added in Example 3 of the present invention on the viscosity of ceramic slurry. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by those skilled in the art without creative effort are still within the scope of protection of the present invention.

[0041] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0042] The refractory brick matrix used in the embodiments and comparative examples of this invention is high-alumina refractory brick (100mm×50mm×25mm). Other types of refractory bricks (such as corundum bricks and magnesia-alumina spinel bricks) can also be applied to the method of this invention.

[0043] Example 1

[0044] This embodiment describes a method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase, comprising the following steps:

[0045] S1 silicon carbide coating modification

[0046] (1) Acid washing to remove impurities: Soak SiC powder in 15wt% hydrochloric acid for 1 hour, and sonicate once every 15 minutes for 15 minutes each time. Then filter, wash with deionized water until pH=7 to remove surface metal impurities, and finally dry at 80℃ for later use.

[0047] (2) Spheroidization treatment: The acid-washed SiC powder was soaked in 12wt% HF for 8min, filtered and dried, and then pre-oxidized in air atmosphere at 780℃ for 2h. Then it was acid-washed with 10wt% HF for 10min and dried at 80℃. The pre-oxidation-acid washing was repeated twice to finally obtain SiC powder with a sphericity of 0.88.

[0048] (3) Silane coupling grafting treatment: The spheroidized SiC powder, KH792, KH560 and deionized water were mixed in a mass ratio of 9:0.8:0.2:9, and placed in a constant temperature water bath at 65℃ for ultrasonication and stirring for 2.5h. After standing, it was washed 3 times with 5 times the volume of deionized water, filtered and dried at 80℃ to obtain SiC powder with adsorbed composite silane.

[0049] (4) PEI synchronous grafting and coating treatment: Under the condition of maintaining magnetic stirring, 10g of adsorbed and compounded silane SiC powder was added to 100mL of PEI aqueous solution with pH=3.5, wherein the concentration of PEI was 6wt%, containing 0.5g of nano SiO2 with a particle size of 20~50nm. After soaking for 1h, the mixture was filtered and dried at 80℃ to obtain grafted PEI and coated modified SiC powder with a particle size of <3μm.

[0050] Preparation of S2 ceramic slurry

[0051] Under magnetic stirring, 5g of grafted PEI-modified SiC powder, 70g of Al2O3 powder, 21g of CMSP, and 4g of compound dispersant were added sequentially to a mixed solvent consisting of 80mL of ethanol and 20mL of ethylene glycol. The CMSP was composed of 8g of CaO, 6g of MgO, 7g of SiO2, and 1g of PbO by mass. The compound dispersant consisted of 3g of TMAH (tetramethylammonium hydroxide) and 1g of citric acid by mass. The mixture was placed in an XQM-2 type variable frequency planetary ball mill for segmented ball milling. First, it was ball milled at a low speed of 150 r / min rotation and 180 r / min revolution for 2 hours; then it was ball milled at a high speed of 200 r / min rotation and 220 r / min revolution for 4 hours, with a ball-to-material ratio of 3:1; finally, it was ball milled at a vacuum of 0.1 MPa using a ZKT-6020 type vacuum defoamer to remove air bubbles from the slurry, resulting in a ceramic slurry with a viscosity of 880 mPa·s and a solid content of 72 wt%.

[0052] S3 refractory brick matrix pretreatment

[0053] The high-alumina refractory brick substrate was successively polished on 120#, 240#, 400#, and 600# silicon carbide sandpaper, and then roughened by sandblasting with 80-mesh Al2O3 abrasive particles. The sandblasting pressure was 0.45 MPa, the distance was 20 cm, and the sandblasting time was 30 s. Subsequently, it was ultrasonically cleaned with anhydrous ethanol and acetone for 20 min each, and dried at 80℃ to obtain a refractory brick substrate with a surface roughness Ra of 4.5 μm.

[0054] S4 Coating Application and Drying

[0055] First, the pretreated refractory brick substrate is immersed in ceramic slurry at a speed of 5 mm / s, left for 10 seconds, and then removed and dried at 80℃ for 1 hour. Then, the slurry is applied to the edges and corners and depressions with a brush to ensure that the wet film thickness is uniform. It is then dried again at 80℃ for 2 hours to remove the solvent.

[0056] S5 Vacuum Sintering

[0057] The refractory brick material obtained from S4 was placed in a vacuum furnace, and the vacuum degree was controlled at 0.5 MPa. The sintering was carried out according to the following procedure: heating up to 700℃ at 5℃ / min and holding for 30 min; heating up to 1200℃ at 3℃ / min and holding for 40 min; heating up to 1400℃ at 2℃ / min and holding for 1.5 h; cooling down to 900℃ at 2℃ / min and cooling to room temperature in the furnace.

[0058] S6 Annealing

[0059] The material was held at 1100℃ for 1 hour, then cooled to 500℃ at a rate of 1℃ / min and cooled in the furnace to obtain a multi-component oxide ceramic-coated refractory brick material with a coating thickness of 95μm containing reinforcing phase.

[0060] Figure 1 This is a SEM image of the ceramic coating prepared in this embodiment. The black dotted phase in the image represents silicon carbide particles, and the grayish-white matrix is ​​an oxide matrix composed of Al2O3 and CMSP. The silicon carbide particles in the image have a uniform particle size between 2 and 4 μm, and the particle size is highly dispersed. The interparticle gaps are fully filled by the oxide matrix, and the coating density is ≥98.7%.

[0061] Example 2

[0062] The only difference between this embodiment and Example 1 is that the amount of PEI-grafted and modified SiC powder in S2 is replaced with 15g. All other steps and conditions are the same, resulting in a refractory brick material with a multi-component oxide ceramic coating containing a reinforcing phase and a coating thickness of 105μm.

[0063] Figure 2The image shows a SEM image of the ceramic coating surface in this embodiment. The SiC particles are distributed in the oxide matrix composed of Al2O3 and CMSP. The distribution is relatively dense, and slight agglomeration occurs in some areas. The particle size of the agglomerates is <15μm, and the coating density is reduced to 98.2%.

[0064] Example 3

[0065] This embodiment investigates the effect of the total amount of KH792 and KH560 compound silane coupling agent on the viscosity of ceramic slurry, with the mass ratio of KH792 to KH560 fixed at 4:1. The specific steps are as follows:

[0066] After completing the acid washing and spheroidizing treatment according to steps (1) to (2) of S1 in Example 1, the spheroidized SiC powder, compound silane coupling agent and deionized water were mixed, and the effect of the amount of compound silane coupling agent added (0wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt% of the total mass of the three) on the viscosity of the slurry was investigated. The other conditions were the same as in Example 1.

[0067] The viscosity of the slurry at different dosages was tested using a rotational viscometer, and the results are as follows: Figure 3 As shown.

[0068] When the silane addition was 0%, the slurry viscosity was 1421 mPa·s. With increasing addition, the viscosity initially decreased significantly to 852 mPa·s. After the addition exceeded 10 wt%, the viscosity tended to stabilize, with a viscosity of 844 mPa·s at 12 wt% and 836 mPa·s at 15 wt%. This is because the coating layer formed by the coupling of the compound silanes provided steric hindrance, and the dispersion effect reached saturation at 10 wt%. Further increasing the addition had minimal impact on the viscosity. Therefore, a further optimized addition of compound silanes was 10–12 wt%.

[0069] Example 4

[0070] This embodiment investigates the effect of the CMSP group distribution ratio on the coating density and performance. The specific steps are as follows:

[0071] Set up CMSP groups with different quality ratios, as follows:

[0072] Group 1: CaO:MgO:SiO2:PbO = 8:6:7:1;

[0073] Group 2: CaO:MgO:SiO2:PbO = 8:6:7:2;

[0074] Group 3: CaO:MgO:SiO2:PbO = 6:6:7:1;

[0075] Group 4: CaO:MgO:SiO2:PbO = 8:8:7:1;

[0076] Group 5: CaO:MgO:SiO2:PbO = 8:6:9:1;

[0077] Comparative group 1: CaO:MgO:SiO2:PbO = 8:6:7:0;

[0078] Comparative group 2: CaO:MgO:SiO2:PbO = 0:6:7:1;

[0079] Comparative group 3: CaO:MgO:SiO2:PbO = 8:0:7:1;

[0080] Comparative group 4: CaO:MgO:SiO2:PbO = 8:6:0:1;

[0081] The composition of the remaining slurry was the same as in Example 1; and the coating, sintering and annealing were completed according to the steps of Example 1. The density of each coating group and the slag loss at 1400℃ were tested, and the results are shown in Table 1.

[0082]

[0083] As shown in Table 1, within the range of Groups 1 to 5, adjusting the mass ratio of CaO, MgO, SiO2, and PbO oxides can yield coatings with high density and low slag loss at 1400℃. This is because the four components synergistically form a continuous aluminosilicate glass phase and anorthite phase, effectively blocking slag ion diffusion. Among them, Group 1 yields the composite coating with the best overall performance. In contrast, Group 1, without the addition of PbO, has an increased liquid phase formation temperature and insufficient quantity, resulting in inadequate filling of interparticle gaps and a decrease in the integrity of the protective barrier. In Group 2, without the addition of CaO, the anorthite phase cannot be formed, relying solely on the glass phase for protection, significantly weakening the resistance to slag erosion and drastically reducing density. In Group 3, without the addition of MgO for adjustment, the liquid phase has poor stability, easily leading to phase separation at high temperatures, resulting in decreased coating density and structural stability. In Group 4, without the addition of SiO2, the interparticle gaps are filled only by the PbO liquid phase, resulting in insufficient density and poor protection.

[0084] Example 5

[0085] This embodiment investigates the effect of different KH792 and KH560 mass ratios on coating density and performance. The specific steps are as follows:

[0086] Set up KH792 and KH560 groups with different mass ratios, as follows:

[0087] Group 1: KH792: KH560 = 4:1;

[0088] Group 2: KH792: KH560 = 3:1;

[0089] Group 3: KH792: KH560 = 1:1;

[0090] Group 4: KH792: KH560 = 1:3;

[0091] Group 5: KH792: KH560 = 4:0;

[0092] The total amount of KH792 and KH560 used was the same as in Example 1, and the other slurry components were the same as in Example 1. The coating, sintering and annealing were completed according to the steps in Example 1. The density of each group of coatings and the slag loss at 1400℃ were tested, and the results are shown in Table 2.

[0093]

[0094] As shown in Table 2, in Group 5, the epoxy groups without KH560 reinforced the binding, resulting in insufficient PEI grafting stability and weaker dispersion effect compared to the compound system. However, as the amount of KH560 increases, the synergistic dispersion and stabilization effects of both systems show a trend of first increasing and then decreasing.

[0095] Example 6

[0096] This example investigates the effect of different mass ratios of CMSP mixed oxides to Al2O3 on the coating density and performance. The CMSP mixed oxides are composed of CaO, MgO, SiO2, and PbO in a mass ratio of 8:6:7:1. The specific steps are as follows:

[0097] Different mass ratios of CMSP mixed oxides to Al2O3 were set up, namely:

[0098] Group 1: CMSP mixed oxides: Al2O3 = 21:70;

[0099] Group 2: CMSP mixed oxides: Al2O3 = 21:52.5;

[0100] Group 3: CMSP mixed oxides: Al2O3 = 21:105;

[0101] Group 4: CMSP mixed oxides: Al2O3 = 25:70;

[0102] Group 5: CMSP mixed oxides: Al2O3 = 0:70;

[0103] The composition of the remaining slurry was the same as in Example 1; and the coating, sintering and annealing were completed according to the steps of Example 1. The density of each coating group and the slag loss at 1400℃ were tested, and the results are shown in Table 3.

[0104]

[0105] Table 3 shows that the mass ratio of CMSP mixed oxide to Al2O3 has a significant impact on the coating's resistance to slag loss. When no CMSP mixed oxide is added in group 5, a continuous aluminosilicate glass phase cannot be formed in the coating, resulting in high porosity and no calcium feldspar phase protection, leading to severe slag erosion. With the increase of CMSP mixed oxide dosage, the coating's density and resistance to slag loss show a trend of first increasing and then decreasing. This is because an appropriate amount of CMSP mixed oxide can provide sufficient liquid phase to fill the interparticle gaps and form a continuous glass phase and calcium feldspar phase with Al2O3; however, when its dosage is too high, the CMSP mixed oxide causes local liquid phase overflow, leading to a decrease in coating surface smoothness and a slight decline in density and protective properties.

[0106] Comparative Example 1

[0107] The only difference between this comparative example and Example 1 is that grafted PEI and modified SiC powder are not added in S2. All other steps and conditions are the same as in Example 1, and a composite material is obtained.

[0108] Comparative Example 2

[0109] The only difference between this comparative example and Example 1 is that nano-SiO2 is not added in step (4) of S1. The remaining steps and conditions are the same as in Example 1, and a composite material is obtained.

[0110] Comparative Example 3

[0111] The only difference between this comparative example and Example 1 is that annealing is not performed; all other steps and conditions are the same as in Example 1, resulting in a composite material.

[0112] Performance test results of Examples 1-2 and Comparative Examples 1-3

[0113] The properties of the refractory bricks prepared in Examples 1-2, Comparative Examples 1-3, and bare high-alumina refractory bricks were tested respectively, and the results are shown in Table 4:

[0114]

[0115] All performance tests were conducted in accordance with GB / T3074.1-2019 (hardness test) and GB / T17390-2021 (thermal shock resistance and corrosion resistance test). Each group of samples was tested 3 times and the average value was taken.

Claims

1. A method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase, characterized in that: A slurry is obtained by mixing powder raw materials, including coated and modified silicon carbide, Al2O3, CMSP mixed oxides and dispersants, with a solvent; the slurry is then coated on the surface of a refractory brick substrate that has been roughened by sandblasting and subjected to vacuum sintering and annealing treatment. The CMSP mixed oxide is composed of CaO, MgO, SiO2 and PbO in a mass ratio of (6~8):(6~8):(7~9):(1~2); the mass ratio of the CMSP mixed oxide to Al2O3 is (21~25):(52.5~105). The silicon carbide reinforcing phase in the ceramic coating is distributed in an oxide matrix composed of Al2O3 and CMSP.

2. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 1, characterized in that: The coated and modified silicon carbide is obtained by sequentially subjecting the acid-washed and impurity-removed silicon carbide powder to spheroidization treatment, silane coupling agent grafting treatment, and PEI simultaneous grafting and coating treatment. The silane coupling agent used in the silane coupling agent grafting treatment is composed of KH792 and KH560.

3. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 2, characterized in that: The conditions for the silane coupling agent grafting treatment are as follows: using a silane coupling agent composed of KH792 and KH560 in a mass ratio of (1~4):(1~3), at a temperature of 50~65℃, for a time of 2~6h, and with ultrasonic assistance. The amount of silane coupling agent used is 5~15wt% of the total amount of silane coupling agent, spheroidized silicon carbide powder and water.

4. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 2, characterized in that: The conditions for PEI synchronous grafting and coating treatment are as follows: silicon carbide powder grafted with silane coupling agent is soaked in a polyethyleneimine-containing aqueous solution with pH 3-4 for 1-3 hours. The concentration of polyethyleneimine in the polyethyleneimine-containing aqueous solution is 6-8 wt%, and it contains nano-SiO2 with a relative amount of 5-20 wt% of the silicon carbide powder grafted with silane coupling agent.

5. A method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to any one of claims 1 to 4, characterized in that: The dispersant is composed of TMAH and citric acid in a mass ratio of (3~5):(1~2).

6. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 5, characterized in that: The solvents include ethanol and ethylene glycol.

7. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 5, characterized in that: The coating method is a combination of dip coating and brush coating.

8. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 1, characterized in that: The vacuum sintering procedure is as follows: first, heat to 700~800℃ and hold for 30~50 min; then heat to 1200~1300℃ and hold for 20~40 min; then heat to 1400~1500℃ and hold for 1~2 h; then cool to 800~900℃ and cool with the furnace, with a vacuum degree of 0.5~1 MPa. The annealing conditions are as follows: hold at 1000~1100℃ for 1~2 hours, then cool down to 500~600℃ and then cool with the furnace.

9. A method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 1 or 8, characterized in that: The surface roughness of the refractory brick matrix roughened by sandblasting is above 4.5 μm.

10. A refractory brick material with a multi-component oxide ceramic coating containing a reinforcing phase, characterized in that: It is obtained by the preparation method according to any one of claims 1 to 9.

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