Refractory brick material comprising a multi-oxide ceramic coating with reinforcing phase and method for its production

Abstract

The application discloses a kind of refractory brick materials of multiple oxide ceramic coating containing reinforcing phase and preparation method thereof, belong to the field of ceramic material preparation.The method is that the powder raw material in the inside such as coated modified silicon carbide, Al2O3, CMSP mixed oxide and dispersing agent is mixed with solvent to obtain slurry;The slurry is coated on the surface of refractory brick matrix after sand blasting roughening, and vacuum sintering and annealing treatment are carried out to obtain it.By the method of the application, the composite material has the advantages of high density, high hardness, tight combination of matrix 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 environment.

Description

Technical Field

[0001] This invention relates to a multi-component oxide ceramic coating refractory brick material containing a reinforcing phase and its preparation method, belonging to the field of ceramic material preparation. Background Technology

[0002] Refractory bricks, as key protective materials for high-temperature industrial kilns, are widely used in cement rotary kilns, hot blast stoves of steel blast furnaces, glass melting furnace walls, and linings of waste incinerators. Their service performance directly affects the kiln's operational safety, production efficiency, and maintenance cycle. While commonly used high-alumina bricks and other refractory materials possess basic high-temperature resistance, they still face serious problems from high-temperature slag erosion and high-temperature oxidative wear during long-term continuous use. Molten slag easily penetrates into the brick body and reacts with it, forming a low-melting-point phase, leading to a loose structure and surface spalling. Simultaneously, high-temperature oxidation reduces the brick's strength, and under the combined influence of airflow erosion and mechanical wear, material damage is further exacerbated.

[0003] To extend the service life of refractory bricks, existing technologies primarily employ methods such as preparing protective coatings on their surfaces, mainly including spraying and traditional slurry sintering. However, these methods all have significant limitations. Spraying is insufficient for covering deep holes, grooves, and complex internal walls, and often requires preheating the substrate to control thermal stress. Traditional slurry sintering, due to the significant difference in thermal expansion coefficients between the coating and the refractory brick substrate, easily leads to low bonding strength and coating peeling. Furthermore, the coating has poor density, making it difficult to effectively resist slag penetration and high-temperature oxidation over a long period, resulting in unstable protective effects.

[0004] Therefore, existing surface coating technologies cannot meet the long-term protection requirements of refractory bricks in harsh high-temperature environments. There is an urgent need to develop a new coating preparation method to improve the bonding performance between the coating and the refractory brick substrate, enhance its density and erosion resistance, thereby achieving more durable and reliable high-temperature protection for refractory bricks. Summary of the Invention

[0005] To address the problems existing in the prior art, the first objective of this invention is to provide a refractory brick material with a multi-component oxide ceramic coating containing a reinforcing phase. This material has advantages such as high density, high hardness, tight bonding between the matrix and the coating, and good resistance to slag erosion at high temperatures, which can meet the long-term protection requirements of refractory bricks in harsh high-temperature environments.

[0006] The second objective of this invention is to provide a method for preparing a multi-component oxide ceramic coating refractory brick material containing a reinforcing phase. This method has a simple preparation process and constructs a continuous and dense interfacial phase through multi-component oxides and alumina, which significantly improves the interfacial bonding strength, density and high-temperature resistance to slag erosion of the coating. It has high raw material utilization, does not require complex molds, and can be adapted to the surface protection needs of complex-shaped refractory bricks such as curved bricks and irregular bricks.

[0007] To achieve the above-mentioned technical objectives, this invention provides a method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase. The method involves mixing powder raw materials, including modified silicon carbide, Al2O3, CMSP mixed oxides, and a dispersant, with a solvent to obtain a slurry. The slurry is then coated onto the surface of a sandblasted and roughened refractory brick substrate, followed by vacuum sintering and annealing to obtain the final product. 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).

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

[0009] The thermal expansion difference between the mainstream refractory brick matrix and the ceramic coating is 6~8×10. -6 The significant temperature difference (°C) makes it difficult for traditional ceramic coatings to achieve a tight bond with the refractory brick substrate. Furthermore, due to the unique ultra-high temperature application scenarios of the refractory brick substrate, the coating density requirement is extremely high. Failure to meet this density requirement directly leads to a reduction in its high-temperature slag resistance, thus preventing the refractory brick from meeting the long-term protection requirements under harsh high-temperature environments. The key to the significantly improved high-temperature slag erosion resistance and interfacial bonding strength of the refractory brick in this invention lies in using an oxide composed of Al2O3 and CMSP as the matrix and synergistically modifying and coating silicon carbide.

[0010] Specifically, this invention constructs a uniformly dispersed multiphase composite structure at the microscopic level by using Al2O3 and a CMSP mixed oxide with a specific composition as the matrix material, and introducing coated modified silicon carbide as the reinforcing phase. First, CaO, MgO, and SiO2 in the CMSP react with Al2O3 to form a quaternary continuous glassy phase of CaO-MgO-Al2O3-SiO2. This glassy phase has low viscosity and good fluidity, which can fully fill the gaps between SiC particles to form a dense protective layer. Simultaneously, it adjusts the coefficient of thermal expansion of the coating, significantly reducing the difference in thermal expansion between it and the refractory brick matrix to a compatible range, thereby effectively alleviating interfacial stress caused by thermal mismatch. In contrast, Al2O3 and SiO2 cannot form a continuous glassy phase, resulting in a loose structure unsuitable for the special environment of refractory bricks. Second, CaO in the CMSP reacts with Al2O3 and SiO2 at high temperatures to form an anorthite phase, which can effectively block the Ca in the slag. 2+ Mg 2+Diffusion into the substrate significantly improves the coating's resistance to slag erosion; simultaneously, CaO and MgO can further lower the eutectic temperature of the aluminosilicate system, promoting Al... 3+ The silicon carbide dissolves and diffuses in the liquid phase, achieving sufficient densification at relatively low temperatures. Furthermore, the coating modification significantly improves the dispersibility and particle size uniformity of SiC particles in the ceramic slurry, not only completely suppressing the agglomeration of micron-sized SiC powder but also promoting the early formation of the aluminosilicate liquid phase, thus enhancing the coating's high-temperature slag resistance. Sandblasting further increases the roughness of the refractory brick, facilitating a tight bond between the coating and the substrate. Vacuum sintering enables the formation and transformation of various phases, resulting in a denser coating structure. Subsequent annealing eliminates internal stresses in both the refractory brick substrate and the coating, stabilizing the crystal phase composition. This synergistic effect gives the ceramic coating excellent resistance to slag penetration and erosion at ultra-high temperatures, while simultaneously forming a strong chemical bond and mechanical interlocking with the refractory brick substrate, thus achieving long-term protection in harsh environments.

[0011] Experiments have shown that the mass ratio of CMSP mixed oxides to Al2O3 has a significant impact on the overall protective performance of the coating. If the CMSP mixed oxide content is too low, it leads to difficulties in coating sintering, preventing the formation of a continuous quaternary glass phase to fill the interparticle gaps at lower sintering temperatures, resulting in increased coating porosity and even a loose structure. Conversely, if the Al2O3 content is too low, it significantly reduces the interfacial bonding strength between the coating and the substrate and makes it difficult to form the anorthite phase, resulting in a substantial decline in the coating's resistance to slag erosion and oxidation.

[0012] Further preferably, the CMSP mixed oxide is composed of CaO, MgO, SiO2 and PbO in a mass ratio of (7~8):(6~8):(7~8):1; even further, the CMSP mixed oxide is composed of CaO, MgO, SiO2 and PbO in a mass ratio of 8:6:7:1.

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

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

[0015] As a preferred embodiment, the coated and modified silicon carbide is obtained by sequentially subjecting acid-washed and impurity-removed silicon carbide powder to spheroidization treatment, silane coupling agent grafting treatment, and PEI simultaneous grafting and coating treatment.

[0016] The silicon carbide particles obtained by the preparation method of this invention have a particle size of 2~4μm in the final coating.

[0017] As a preferred embodiment, the spheroidization treatment conditions are as follows: silicon carbide powder is immersed in HF, then pre-oxidized by holding it in air at 780-900°C for 2-4 hours, followed by HF acid washing and drying. During the spheroidization process of this invention, holding it in air promotes preferential oxidation to silicon dioxide at sharp points on the silicon carbide surface, which is then removed with hydrofluoric acid, resulting in silicon carbide powder with higher sphericity. Furthermore, the pre-oxidation treatment and acid washing are repeated 2-4 times.

[0018] As a preferred embodiment, 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 this invention, the silane chains of KH792 and KH560 and the amino chains of polyethyleneimine (PEI) are bonded by hydrogen bonds to form a double coating layer, which thoroughly suppresses the agglomeration of micron-sized SiC powder. At the same time, 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 embodiment, the silane coupling agent grafting treatment conditions 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 2~6 hours, 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. More preferably, the mass ratio of KH792 to KH560 is (3~4):(1~2).

[0020] As a preferred embodiment, the conditions for simultaneous PEI grafting and coating treatment are as follows: silicon carbide powder grafted with a silane coupling agent is soaked in a polyethyleneimine-containing aqueous solution with a pH of 3-4 for 1-3 hours. The concentration of polyethyleneimine in the aqueous solution is 6-8 wt%, and the powder contains 5-20 wt% nano-SiO2 relative to the amount of silicon carbide powder grafted with the silane coupling agent. This invention, by adding a small amount of nano-sized SiO2 during the coating process, not only further improves the dispersibility of the powder but also utilizes the abundant silanol groups on its surface to form a strong bond on the PEI and silicon carbide surfaces, enhancing the adhesion of the coating layer and simultaneously improving the particle size uniformity of SiC particles.

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

[0022] As a preferred embodiment, the spheroidization process further includes acid washing to remove impurities.

[0023] Furthermore, the acid pickling and impurity removal process is as follows: the silicon carbide powder is immersed in hydrochloric acid, ultrasonically operated 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 consisted 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 and 180 r / min for 2 hours. Then, it was ball milled at a high speed of 200 r / min and 220 r / min for 4 hours, with a ball-to-material ratio of 3:1. Finally, a ZKT-6020 type vacuum defoamer was used to remove air bubbles from the slurry at a vacuum degree of 0.1 MPa to obtain 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). In the ceramic coating, the silicon carbide reinforcing phase is distributed in the oxide matrix composed of Al2O3 and CMSP; 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. 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.

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 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.

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 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.

4. 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 3, characterized in that: The dispersant is composed of TMAH and citric acid in a mass ratio of (3~5):(1~2).

5. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 4, characterized in that: The solvents include ethanol and ethylene glycol.

6. The method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 4, characterized in that: The coating method is a combination of dip coating and brush coating.

7. 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.

8. A method for preparing a multi-component oxide ceramic-coated refractory brick material containing a reinforcing phase according to claim 1 or 7, characterized in that: The surface roughness of the refractory brick matrix roughened by sandblasting is above 4.5 μm.

9. 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 8.

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