A multi-layer calcium titanate reinforced calcium hexaluminate composite material and a preparation process thereof

Abstract

The application belongs to the technical field of refractory raw materials, and particularly relates to a kind of layered calcium titanate reinforced calcium hexaluminate composite materials and its preparation process, including modified calcium hexaluminate, modified calcium titanate, alpha-Al2O3 micro powder, calcium carbonate micro powder. The application modifies calcium titanate with phenyl phosphonic acid, and the phosphorus component participates in the shell interface reaction in sintering, which improves the shell density and crack propagation resistance. The application modifies calcium hexaluminate with decanoic acid and pyrolyzes carbonization, and the carbon interface layer plays a buffering role for the core-shell thermal mismatch stress in the low-temperature sintering stage. After carbon burning, size-controlled closed micropores are formed and do not constitute a connected permeation channel, which provides a stress release space for the volume effect of the calcium titanate shell phase change. The two synergies make the shell keep dense and continuous, the TiO2 permeation barrier function can be stably played, the core layer calcium hexaluminate structure is effectively protected, and the product erosion life is improved.

Description

Technical Field

[0001] This invention belongs to the field of refractory raw material technology, specifically a multilayered calcium titanate reinforced calcium hexaaluminate multiphase material and its preparation process. Background Technology

[0002] Calcium titanate (CaTiO3) is a perovskite-type ceramic oxide with a high melting point, good thermal stability, and chemical stability, and is widely used in the field of refractory materials. Using CaTiO3 as the shell component of multiphase refractory materials can inhibit the penetration of external TiO2 into the material interior through its chemical potential balancing effect on TiO2, thereby protecting the crystal structure stability of the core layer calcium hexaaluminate (CA6).

[0003] However, the long-term stability of the CaTiO3 shell under high TiO2 chemical potential conditions is questionable. According to the CaO-TiO2 binary phase diagram, this system contains several intermediate compounds, including Ca3Ti2O7 and Ca4Ti3O7. 10 A titanium-rich mesophase. When the CaTiO3 shell is continuously exposed to the high chemical potential TiO2 melt, the continuous increase in TiO2 activity drives the thermodynamic equilibrium of the system to shift from the CaTiO3 single-phase stable region to the titanium-rich phase region. This promotes the reaction between CaTiO3 and the continuously infiltrated TiO2, gradually transforming it into a high-titanium mesophase. This phase evolution process has a clear thermodynamic driving force under high-temperature long-term service conditions.

[0004] Accompanying the aforementioned phase transition process, the molar volumes of each phase differ, and the local volume changes induced by the phase transition generate internal stress within the shell. Under repeated thermal cycling conditions, the accumulated internal stress is released in the form of microcracks, leading to the destruction of the shell's compactness. Once the shell's continuity is lost, the TiO2 shielding function established based on chemical potential equilibrium fails, and the CA6 core layer is re-exposed to TiO2 penetration and erosion, posing a risk of overall failure to the multilayer protection mechanism. Summary of the Invention

[0005] (1) Technical problems to be solved

[0006] The purpose of this invention is to provide a multilayered calcium titanate-reinforced calcium hexaaluminate composite material and its preparation process, in order to solve the problem that the CaTiO3 shell undergoes a phase transition to a high titanium phase under high temperature and high TiO2 chemical potential, accompanied by volume expansion, which leads to the destruction of the shell's compactness, loss of the chemical potential barrier function, and thus exposes the core CA6 layer to the risk of TiO2 permeation.

[0007] (2) Technical solution

[0008] To achieve the above objectives, on the one hand, the present invention provides a multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material, comprising the following components in parts by weight: 55-70 parts modified calcium hexaaluminate, 15-30 parts modified calcium titanate, 5-10 parts α-Al2O3 micro powder, and 2-5 parts calcium carbonate micro powder.

[0009] The modified calcium titanate is obtained by modifying calcium titanate with phenylphosphonic acid; the modified calcium hexaaluminate is obtained by modifying calcium hexaaluminate with decanoic acid and then carbonizing it by pyrolysis in an inert atmosphere.

[0010] The phase composition of the multilayered calcium titanate-reinforced calcium hexaaluminate composite material includes a calcium hexaaluminate main crystalline phase and a calcium titanate secondary crystalline phase; after sintering, the composite material forms a core-shell structure with calcium hexaaluminate particles as the core layer and calcium titanate as the continuous shell layer.

[0011] Furthermore, the α-Al₂O₃ micro powder has a purity ≥99.5% and a median particle size D. 50 ≤2μm; the purity of the calcium carbonate micro powder is ≥98%, and the median particle size D 50 ≤5μm.

[0012] Furthermore, the preparation method of the modified calcium titanate includes the following steps:

[0013] S11. Immerse the calcium titanate powder in a 0.1 mol / L nitric acid solution and stir. After treatment, wash repeatedly with deionized water and then dry to obtain activated calcium titanate.

[0014] S12. Immerse activated calcium titanate in a mixed solution of phenylphosphonic acid and stir to react; after the reaction is complete, wash repeatedly with anhydrous ethanol; then dry to obtain modified calcium titanate.

[0015] Furthermore, the calcium titanate powder has a purity of ≥99% and a median particle size D. 50 The particle size is 1-5 μm; the solid-liquid ratio of the calcium titanate powder to the 0.1 mol / L nitric acid solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0016] Further, the phenylphosphonic acid mixed solution is a mixture of phenylphosphonic acid in ethanol and water, with a concentration of 10-15 mmol / L and a volume ratio of ethanol to water of 9:1; the solid-liquid ratio of the activated calcium titanate and phenylphosphonic acid mixed solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0017] Furthermore, the preparation method of the modified calcium hexaaluminate includes the following steps:

[0018] S21. The calcium hexaaluminate powder was ultrasonically cleaned with anhydrous ethanol; filtered and dried to obtain clean calcium hexaaluminate powder.

[0019] S22. Immerse the clean calcium hexaaluminate powder in a 0.5 mol / L sodium hydroxide solution for soaking treatment; after treatment, wash repeatedly with deionized water; then dry to obtain activated calcium hexaaluminate;

[0020] S23. Immerse activated calcium hexaaluminate in an ethanol solution of decanoic acid and stir to react; after the reaction is complete, wash repeatedly with anhydrous ethanol; then dry to obtain the precursor;

[0021] S24. The precursor is pyrolyzed and carbonized under an inert atmosphere to obtain modified calcium hexaaluminate.

[0022] Furthermore, the calcium hexaaluminate powder has a purity of ≥98% and a median particle size D. 50 The particle size is 20-50 μm; the solid-liquid ratio of the clean calcium hexaaluminate powder to the 0.5 mol / L sodium hydroxide solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0023] Furthermore, the concentration of the decanoic acid ethanol solution is 8-12 mmol / L; the solid-liquid ratio of the activated calcium hexaaluminate to the decanoic acid ethanol solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0024] Furthermore, the preparation process of the aforementioned multilayered calcium titanate-reinforced calcium hexaaluminate composite material includes the following steps:

[0025] S1. Modified calcium hexaaluminate, modified calcium titanate, α-Al2O3 micro powder, and calcium carbonate micro powder are mixed evenly to obtain a multilayered calcium titanate-reinforced calcium hexaaluminate composite material.

[0026] (3) Beneficial effects

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. The phosphorus component introduced into the modified calcium titanate of this invention participates in the shell-layer interface reaction during the sintering process of preparing refractory products, which helps to improve the structural density and crack propagation resistance of the shell layer, enabling the shell layer of the product to maintain structural integrity under multiple thermal cycling service conditions. The carbon-containing interface transition layer formed by the pyrolysis and carbonization of modified calcium hexaaluminate serves as a transitional flexible interface during the low-temperature stage of product sintering (400-600℃), playing a certain role in buffering the thermal mismatch stress between the core and shell. After carbon is oxidized in an air atmosphere, micropores are formed at the interface. The interface micropores are locally closed pores, the size of which is controlled by the concentration of decanoic acid, and do not form interconnected permeation channels. During the high-temperature service of the product, they provide local stress release space for the phase transformation volume effect of the calcium titanate shell layer, which is beneficial to suppressing the propagation of phase transformation microcracks.

[0029] 2. The synergistic effect of the above two factors ensures that the calcium titanate shell in the product maintains its density and continuity under long-term high-temperature service conditions. The TiO2 permeation barrier function established by the chemical potential equilibrium is stably maintained, and the crystal structure stability of the core layer of calcium hexaaluminate is effectively protected. Due to the guaranteed long-term effectiveness of the shell protection mechanism, the multilayered core-shell structure is less prone to overall failure under harsh service environments with high TiO2 chemical potential, thus improving the high-temperature stability and corrosion resistance life of the prepared refractory product.

[0030] 3. α-Al2O3 micro powder is introduced into the raw material system as an auxiliary component. It can fill the gaps between particles, improve the packing density of the raw material, and help improve the overall density and room temperature flexural strength of the product during the subsequent sintering process. Calcium carbonate micro powder is introduced into the raw material system as an active calcium source component. During the subsequent sintering process, it decomposes to provide active CaO, which can react with trace amounts of TiO2 in the system to supplement CaTiO3 in situ. This helps stabilize the shell phase composition and ensure the integrity of the shell structure of the product. Attached Figure Description

[0031] Figure 1 This is a physical image of a multilayered calcium titanate-reinforced calcium hexaaluminate composite material according to the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1: This example discloses a multilayered calcium titanate-reinforced calcium hexaaluminate composite material, comprising the following components in parts by weight: 62.5 parts modified calcium hexaaluminate, 22.5 parts modified calcium titanate, 7.5 parts α-Al2O3 micro powder, and 3.5 parts calcium carbonate micro powder;

[0034] The modified calcium titanate is obtained by modifying calcium titanate with phenylphosphonic acid; the modified calcium hexaaluminate is obtained by modifying calcium hexaaluminate with decanoic acid and then carbonizing it by pyrolysis in an inert atmosphere.

[0035] The phase composition of the multilayered calcium titanate-reinforced calcium hexaaluminate composite material includes a calcium hexaaluminate main crystalline phase and a calcium titanate secondary crystalline phase; after sintering, the composite material forms a core-shell structure with calcium hexaaluminate particles as the core layer and calcium titanate as the continuous shell layer.

[0036] The α-Al2O3 micro powder has a purity of ≥99.5% and a median particle size D. 50≤2μm; the purity of the calcium carbonate micro powder is ≥98%, and the median particle size D 50 ≤5μm.

[0037] The preparation method of the modified calcium titanate includes the following steps:

[0038] S11. Immerse the calcium titanate powder in a 0.1 mol / L nitric acid solution and stir at room temperature for 1-3 hours. After treatment, wash repeatedly with deionized water until the washing solution is neutral. Then dry at 60-80℃ for 2 hours to obtain activated calcium titanate.

[0039] S12. Immerse activated calcium titanate in a mixed solution of phenylphosphonic acid and stir in a constant temperature water bath at 60-80℃ for 4-8 hours. After the reaction is complete, wash repeatedly with anhydrous ethanol 3-5 times. Then dry at 60-80℃ for 2 hours to obtain modified calcium titanate.

[0040] The calcium titanate powder has a purity of ≥99% and a median particle size D. 50 The particle size is 1-5 μm; the solid-liquid ratio of the calcium titanate powder to the 0.1 mol / L nitric acid solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0041] The phenylphosphonic acid mixed solution is a mixture of phenylphosphonic acid in ethanol and water, with a concentration of 10-15 mmol / L and a volume ratio of ethanol to water of 9:1; the solid-liquid ratio of the activated calcium titanate and phenylphosphonic acid mixed solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0042] The preparation method of the modified calcium hexaaluminate includes the following steps:

[0043] S21. Ultrasonically clean the calcium hexaaluminate powder with anhydrous ethanol for 10-15 min; filter and dry at 60-80℃ for 2 h to obtain clean calcium hexaaluminate powder.

[0044] S22. Immerse the clean calcium hexaaluminate powder in a 0.5 mol / L sodium hydroxide solution at room temperature for 1-2 hours. After treatment, wash repeatedly with deionized water until the washing solution is neutral. The conductivity of the final washing solution should not exceed 10 μS / cm, as measured by a conductivity meter, to ensure that the Na... + The residual amount was within an acceptable range; subsequently, it was dried at 60-80℃ for 2 hours to obtain activated calcium hexaaluminate.

[0045] S23. Immerse activated calcium hexaaluminate in an ethanol solution of decanoic acid and stir at a constant temperature of 60-80℃ for 4-8 hours; after the reaction is complete, wash repeatedly with anhydrous ethanol 3-5 times; then dry at 60-80℃ for 2 hours to obtain the precursor;

[0046] S24. Place the precursor in a tube furnace, first introduce nitrogen gas into the furnace at a flow rate of 30-60 mL / min to replace the air in the furnace for at least 30 min, then heat to 700-800℃ at a heating rate of 5℃ / min under continuous nitrogen gas supply, hold for 1-2 h, and cool to room temperature with the furnace after the holding period to obtain modified calcium hexaaluminate.

[0047] The calcium hexaaluminate powder has a purity of ≥98% and a median particle size D. 50 The particle size is 20-50 μm; the solid-liquid ratio of the clean calcium hexaaluminate powder to the 0.5 mol / L sodium hydroxide solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0048] The concentration of the decanoic acid ethanol solution is 8-12 mmol / L; the solid-liquid ratio of the activated calcium hexaaluminate to the decanoic acid ethanol solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

[0049] It should be noted that the median particle size D of the modified calcium hexaaluminate is... 50 The median particle size D of modified calcium titanate is controlled within 20-50 μm. 50 The particle size is controlled within 1-5 μm. The particle size difference allows CaTiO3 micro powder to be evenly distributed around CA6 particles, forming a continuous core-shell coating layer under the sintering driving force.

[0050] The preparation process of the aforementioned multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material includes the following steps:

[0051] S1. Modified calcium hexaaluminate, modified calcium titanate, α-Al₂O₃ micro powder, and calcium carbonate micro powder are mixed evenly to obtain a multilayered calcium titanate-reinforced calcium hexaaluminate composite material. For example... Figure 1 This is a physical image of the multilayered calcium titanate-reinforced calcium hexaaluminate composite material of the present invention.

[0052] It should be noted that the aforementioned multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material is a refractory raw material powder for downstream applications. The method for preparing it into refractory products is as follows: Take the multiphase material (i.e., a mixed powder of four components: modified calcium hexaaluminate, modified calcium titanate, α-Al₂O₃ micro powder, and calcium carbonate micro powder), and add a 5% polyvinyl alcohol solution (3-6% by mass of the total mass of the four components) as a temporary binder, mixing thoroughly. Press the mixture under a pressure of 10-30 MPa using a machine pressing method to obtain a green body. Dry the green body at 60-80℃ for 4-6 hours, then place it in a high-temperature furnace and heat it to 1450-1550℃ in air at a heating rate of 3-5℃ / min, holding for 2-4 hours. Cool it to room temperature with the furnace to obtain the multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material product.

[0053] Example 2: This example is based on Example 1, but differs from Example 1 in that it includes the following components in parts by weight: 55 parts modified calcium hexaaluminate, 15 parts modified calcium titanate, 5 parts α-Al2O3 micro powder, and 2 parts calcium carbonate micro powder.

[0054] The other components and preparation process are the same as in Example 1.

[0055] Example 3: This example is based on Example 1, but differs from Example 1 in that it includes the following components in parts by weight: 70 parts modified calcium hexaaluminate, 30 parts modified calcium titanate, 10 parts α-Al2O3 micro powder, and 5 parts calcium carbonate micro powder.

[0056] The other components and preparation process are the same as in Example 1.

[0057] Comparative Example 1: This comparative example is based on Example 1, but differs from Example 1 in that the modified calcium titanate in this comparative example is not modified with phenylphosphonic acid, i.e., it is unmodified calcium titanate; other components and preparation processes are the same as in Example 1.

[0058] Comparative Example 2: This comparative example differs from Example 1 in that the modified calcium titanate is replaced with unmodified calcium titanate, and 0.18 parts of calcium phosphate powder (purity ≥98%, median particle size D) are added. 50 (≤5μm); other components and preparation process are the same as in Example 1.

[0059] Comparative Example 3: This comparative example is based on Example 1, but differs from Example 1 in that the modified calcium hexaaluminate in this comparative example is not modified with decanoic acid and subjected to inert atmosphere pyrolysis carbonization treatment, i.e., it is unmodified calcium hexaaluminate; other components and preparation processes are the same as in Example 1.

[0060] Comparative Example 4: This comparative example is based on Example 1, but differs from Example 1 in that the modified calcium hexaaluminate described in this comparative example is only modified with decanoic acid (i.e., only steps S21-S23 are performed), and the pyrolysis carbonization treatment of S24 is not performed; other components and preparation processes are the same as in Example 1.

[0061] Comparative Example 5: This comparative example is based on Example 1, except that the modified calcium titanate is replaced with unmodified calcium titanate and the modified calcium hexaaluminate is replaced with unmodified calcium hexaaluminate; the other components and preparation process are the same as in Example 1.

[0062] Comparative Example 6: This comparative example is based on Example 1, but unlike Example 1, no α-Al2O3 micro powder is added in this comparative example; other components and preparation processes are the same as in Example 1.

[0063] Comparative Example 7: This comparative example is based on Example 1, but unlike Example 1, no calcium carbonate micro powder is added in this comparative example; other components and preparation processes are the same as in Example 1.

[0064] Experimental verification:

[0065] According to the above-mentioned method for preparing refractory products, the multilayered calcium titanate-reinforced calcium hexaaluminate composite materials obtained in Examples 1-3 and Comparative Examples 1-7 were respectively prepared into sintered blocks.

[0066] Experimental Example 1: High-Temperature TiO2 Erosion Mass Increment and Volume Expansion Test

[0067] (1) Test methods

[0068] The sintered blocks were processed into cylindrical samples of φ20mm×20mm, with 5 samples per group. The dimensions were measured using vernier calipers, and the sample surface area S0 (mm²) was calculated. The initial mass m0 (mg) was weighed using an analytical balance with a precision of 0.01 mL, and the initial volume V0 (mm³) was determined using the water displacement method. The sample was completely embedded in analytical grade TiO₂ powder, placed in a corundum crucible, and heated to 1550℃ at a rate of 5℃ / min, held for 10 h, and then cooled with the furnace. After removal, the surface powder was brushed off with a soft brush, ultrasonically cleaned in anhydrous ethanol for 2 min, and dried at 100℃ for 2 h. The mass m1 was weighed again, and the volume V1 was determined using the water displacement method.

[0069] (2) Calculation formula

[0070] Mass increment per unit surface area: ;

[0071] Volume expansion rate: ;

[0072] Calculate the mass increment per unit surface area ( ) and volume expansion rate ( The smaller the mass increment (V), the less TiO2 penetrates and the stronger the shell barrier function; the smaller the volume expansion rate, the weaker the volume effect caused by the phase transformation of the calcium titanate shell to the high titanium phase.

[0073] Test Example 2: Residual Strength Test After Thermal Shock Cycling

[0074] (1) Test methods

[0075] The room temperature flexural strength test was performed according to GB / T 3001-2017 "Test Method for Room Temperature Flexural Strength of Refractory Materials". The sintered block was prepared into strip specimens of 25mm × 25mm × 150mm, with 6 specimens per group. The room temperature flexural strength before thermal shock was measured. (Three-point bending method, span 125mm, loading speed 0.5mm / min). Another sample from the same batch was taken and, following the operating conditions of the water-cooling method in GB / T 30873-2014, held at 1100℃ for 20min, then rapidly immersed in 25℃ water for quenching. This cycle was repeated 5 times, and the residual flexural strength after thermal shock was measured. Calculate the flexural strength retention rate.

[0076] (2) Calculation formula

[0077] Flexural strength: ;

[0078] Strength retention rate: ;

[0079] In the formula, F is the fracture load (N), L is the span (mm), b is the specimen width (mm), and h is the specimen height (mm).

[0080] Table 1 Experimental Data Results

[0081] As shown in Table 1, Examples 1-3 exhibited superior resistance to permeation, volume stability, and thermal shock resistance compared to all comparative examples. The absence of any single modifying component resulted in significant performance degradation, with the most severe degradation occurring when both components were synergistically absent. The addition of calcium phosphate had limited effect; the carbon-containing interfacial transition layer required pyrolysis and carbonization to function. Comparative Example 4, modified only with decanoic acid without carbonization, suffered from disordered pyrolysis of organic residues during high-temperature sintering, forming non-uniform pores at the interface. This slightly disrupted the shell's density, resulting in slightly lower performance than the completely unmodified Comparative Example 3. While auxiliary components contributed to the performance, core-shell chemical modification remained the dominant factor determining resistance to TiO2 erosion.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material, characterized in that, It is composed of the following components in parts by weight: 55-70 parts modified calcium hexaaluminate, 15-30 parts modified calcium titanate, 5-10 parts α-Al2O3 micro powder, and 2-5 parts calcium carbonate micro powder. The phase composition of the multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material includes a calcium hexaaluminate main crystalline phase and a calcium titanate secondary crystalline phase; after sintering, the multiphase material forms a core-shell structure with calcium hexaaluminate particles as the core layer and calcium titanate as the continuous shell layer. The preparation method of the modified calcium titanate includes the following steps: S11. Immerse the calcium titanate powder in a 0.1 mol / L nitric acid solution and stir. After treatment, wash repeatedly with deionized water and then dry to obtain activated calcium titanate. S12. Immerse activated calcium titanate in a mixed solution of phenylphosphonic acid and stir to react; after the reaction is complete, wash repeatedly with anhydrous ethanol; then dry to obtain modified calcium titanate; The preparation method of the modified calcium hexaaluminate includes the following steps: S21. The calcium hexaaluminate powder was ultrasonically cleaned with anhydrous ethanol; filtered and dried to obtain clean calcium hexaaluminate powder. S22. Immerse the clean calcium hexaaluminate powder in a 0.5 mol / L sodium hydroxide solution for soaking treatment; after treatment, wash repeatedly with deionized water; then dry to obtain activated calcium hexaaluminate; S23. Immerse activated calcium hexaaluminate in an ethanol solution of decanoic acid and stir to react; after the reaction is complete, wash repeatedly with anhydrous ethanol; then dry to obtain the precursor; S24. The precursor is pyrolyzed and carbonized under an inert atmosphere to obtain modified calcium hexaaluminate.

2. The multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material according to claim 1, characterized in that, The α-Al2O3 micro powder has a purity of ≥99.5% and a median particle size D. 50 ≤2μm; the purity of the calcium carbonate micro powder is ≥98%, and the median particle size D 50 ≤5μm.

3. The multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material according to claim 1, characterized in that, The calcium titanate powder has a purity of ≥99% and a median particle size D. 50 The particle size is 1-5 μm; the solid-liquid ratio of the calcium titanate powder to the 0.1 mol / L nitric acid solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

4. The multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material according to claim 1, characterized in that, The phenylphosphonic acid mixed solution is a mixture of phenylphosphonic acid in ethanol and water, with a concentration of 10-15 mmol / L and a volume ratio of ethanol to water of 9:1; the solid-liquid ratio of the activated calcium titanate and phenylphosphonic acid mixed solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

5. The multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material according to claim 1, characterized in that, The calcium hexaaluminate powder has a purity of ≥98% and a median particle size D. 50 The particle size is 20-50 μm; the solid-liquid ratio of the clean calcium hexaaluminate powder to the 0.5 mol / L sodium hydroxide solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

6. The multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material according to claim 1, characterized in that, The concentration of the decanoic acid ethanol solution is 8-12 mmol / L; the solid-liquid ratio of the activated calcium hexaaluminate to the decanoic acid ethanol solution is 1:3-1:5; the unit of the solid-liquid ratio is g / mL.

7. A preparation process for a multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material, applied to the preparation of the multilayered calcium titanate-reinforced calcium hexaaluminate multiphase material as described in any one of claims 1 to 6, characterized in that, The process includes the following steps: S1. Modified calcium hexaaluminate, modified calcium titanate, α-Al2O3 micro powder, and calcium carbonate micro powder are mixed evenly to obtain a multilayered calcium titanate-reinforced calcium hexaaluminate composite material.

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