Aluminum titanate material, preparation method thereof, and ceramic material having the same

Abstract

The present invention discloses an aluminum titanate material, which comprises the following components, by mass percentage: alumina powder: 40-45%; titanium dioxide: 35-40%; MgCO3: 10-20%; ZnO: 3-5%; and Fe2O3: 2-4%. The present invention also discloses a method for preparing the aluminum titanate material and a ceramic material containing the aluminum titanate material. The aluminum titanate material provided by the present invention provides aluminum titanate with a highly corrosive and low-expansion main crystal phase by using Al2O3 and TiO2. When ZnO and Fe2O3 are in a specific ratio and combined with a specific ratio of MgCO3, the reaction temperature and reaction time of the aluminum titanate material can be effectively reduced. The prepared aluminum titanate material can be sintered at a temperature of 1400°C for 2 hours. The prepared aluminum titanate material sintered body not only has greatly improved mechanical strength, but also does not lose the low thermal expansion coefficient and corrosion resistance inherent to the aluminum titanate sintered body.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic non-metallic ceramic materials, and particularly relates to an aluminum titanate material, a preparation method thereof, and a ceramic material comprising the same. Background Art

[0002] Aluminum titanate sintered bodies have a low thermal expansion coefficient and high corrosion resistance. They are considered heat-resistant materials. When used as containers, ladles, or troughs for molten metals such as aluminum, aluminum alloys, and iron alloys, they exhibit low wettability with molten slag, excellent corrosion resistance, superior spalling strength, and other excellent properties. However, the grains that comprise aluminum titanate sintered bodies are anisotropic, and these bodies tend to have the following disadvantages: when heated or cooled, stress generated by the anisotropic thermal expansion coefficient causes displacement of grain boundaries, resulting in the formation of microcracks and pores, which can lead to low mechanical strength.

[0003] Therefore, the conventional aluminum titanate sintered body has insufficient strength and cannot exhibit sufficient durability particularly when subjected to high temperatures and moderate loads.

[0004] In addition, aluminum titanate is unstable at temperatures of 1280° C. or below. When used in the temperature range of 800-1280° C., the compound tends to decompose into TiO2 and Al2O3, making it difficult to continuously use the material at such high temperatures.

[0005] To improve the sinterability of aluminum titanate and prevent its thermal decomposition, additives such as silica are added to the raw materials before sintering. However, this tends to reduce the solvent resistance of the resulting sintered body. Consequently, it is impossible to obtain a refractory aluminum titanate sintered body that can be used at temperatures as high as approximately 1400°C and also has high mechanical strength. Summary of the Invention

[0006] The present invention aims to address, at least to some extent, one of the technical problems in the related art. To this end, the present invention primarily aims to provide an aluminum titanate material that addresses the technical problem of existing aluminum titanates capable of being used at temperatures up to approximately 1400°C while also exhibiting high mechanical strength. The present invention also provides a method for preparing the aluminum titanate material and a ceramic material comprising the same.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] An aluminum titanate material comprises the following components, calculated by mass percentage: alumina powder: 40-45%; titanium dioxide: 35-40%; MgCO3: 10-20%; ZnO: 3-5%; and Fe2O3: 2-4%.

[0009] In certain specific embodiments, it includes the following components: aluminum oxide powder: 40%; titanium dioxide: 35%; MgCO3: 18%; ZnO: 5%; Fe2O3: 2%.

[0010] In certain specific embodiments, it includes the following components: aluminum oxide powder: 45%; titanium dioxide: 35%; MgCO3: 13%; ZnO: 3%; Fe2O3: 4%.

[0011] A method for preparing the aluminum titanate material according to the above-mentioned method comprises the following steps:

[0012] A1) mixing aluminum oxide powder, titanium dioxide, MgCO3, ZnO, and Fe2O3 to obtain a mixture;

[0013] A2) adding water to the mixture, stirring evenly, and then filtering to form a cake;

[0014] A3) The cake is formed into bricks by a vacuum clay machine and dried for later use;

[0015] A4) Place the material in a high-temperature kiln and sinter it in an oxidizing atmosphere to obtain aluminum titanate.

[0016] In some specific embodiments, the firing conditions in step A4) are: firing temperature is 1400° C., and firing time is 2 hours.

[0017] A ceramic material containing aluminum titanate prepared by the above preparation method comprises the following components by mass percentage: kaolin: 10-20%; aluminum titanate: 65-70%; zirconium silicate: 5-10%; silicon dioxide: 5-15%.

[0018] In certain specific embodiments, the ceramic material is prepared by the following preparation method:

[0019] B1) mixing kaolin, aluminum titanate, ZrSiO4 and SiO2 according to mass ratio;

[0020] B2) adding water to the mixture obtained in step A1, stirring uniformly, and then filtering to form a cake;

[0021] B3) passing the cake through a vacuum mud kneader into mud strips for later use;

[0022] B4) forming the clay strips into products;

[0023] B5) The product is fired in a high-temperature kiln and then naturally cooled to room temperature to obtain a ceramic material.

[0024] In some specific implementations, the firing conditions are: in an oxidizing atmosphere, a firing temperature of 1400° C., and a firing time of 1-2 hours.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1) The aluminum titanate material provided by the present invention has improved strength of its sintered body to a level that can be used in practical applications and can be used at high temperatures. It also has the inherent properties of aluminum titanate, namely, low thermal expansion coefficient and high corrosion resistance.

[0027] 2) The aluminum titanate material provided in the present application provides aluminum titanate with a highly corrosive and low-expansion main crystal phase by adopting Al2O3 and TiO2, and when ZnO and Fe2O3 are in a specific ratio and combined with a specific ratio of MgCO3, it can effectively reduce the reaction temperature and reaction time of the aluminum titanate material. The prepared aluminum titanate material is sintered at a temperature of 1400°C for 2h; and the prepared aluminum titanate material sintered body not only has greatly improved mechanical strength, but also does not lose the low thermal expansion coefficient and corrosion resistance inherent in the aluminum titanate sintered body.

[0028] 3) The ceramic material provided in this application has a linear expansion coefficient of less than 1.0*10 at a temperature of 20°C-750°C. -6 ℃, kaolin decomposes at high temperature and reacts with SiO2 to form mullite that is evenly distributed around aluminum titanate, greatly enhancing its strength; at the same time, SiO2 can also be dissolved into the aluminum titanate material to increase its stability, and ZrSiO4 is evenly distributed in the grain boundaries of each main crystal phase to play a toughening role. Through the synergistic effect of various raw materials, the linear expansion coefficient of the ceramic material at a temperature of 20℃-750℃ is less than 1.0*10 -6 ℃, with excellent comprehensive properties such as high strength, low water absorption and high thermal shock resistance. In addition, the sintered body of the aluminum titanate material has excellent resistance to thermal decomposition, shows high melting resistance and can be used stably at high temperatures. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below with reference to specific examples. The following examples are merely illustrative and non-restrictive, and should not be used to limit the scope of protection of the present invention.

[0030] When expressing a certain amount, concentration or other value or parameter in the form of a range, preferred range, or preferred upper and lower numerical limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, without considering whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within the range.

[0031] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0032] The materials, methods, and examples herein are illustrative and, unless otherwise indicated, are not to be construed as limiting.

[0033] In the following examples, the composition of the kaolin in terms of mass percentage is as follows: 46.54% SiO2, 39.5% Al2O3, 13.15% H2O, and Na2O≤0.51%, and Ca and MgO≤0.3%.

[0034] The content of ZrO2 in the zirconium silicate is ≥65wt%, and the particle size is 5-15μm.

[0035] The SiO2 content in the silicon dioxide is ≥99.5wt%, and the particle size is less than 3-8um.

[0036] Among them, the synthesis of aluminum titanate by sintering a mixture of Al2O3 and TiO2 belongs to the existing technology, so there is no special restriction on the raw materials Al2O3 and TiO2.

[0037] In the following embodiments, the corrosion resistance test method is: the number of times the surface does not fall off after adding and pouring molten aluminum liquid;

[0038] Decomposition rate: After the product is cooled from 1100℃ to room temperature for 30 times, the percentage of TiO2 (titanium dioxide) in the product is measured.

[0039] Example 1

[0040] The preparation method of aluminum titanate material provided by the present invention comprises the following steps:

[0041] A1) mixing 40% alumina powder, 35% titanium dioxide, 18% MgCO3, 5% ZnO, and 2% Fe2O3;

[0042] A2) adding water to the mixture obtained in step A1), stirring uniformly, and then filtering to form a cake;

[0043] A3) The cake is passed through a vacuum clay machine to form machine-pressed bricks with a size of 230mm*115mm*65mm;

[0044] A4) The machine-pressed bricks are dried naturally until the moisture content is less than 15%. They are then placed in a high-temperature kiln and baked at 250°C for 3 hours. The temperature is then raised to 1400°C over 12 hours. The bricks are kept at this temperature for 1.5 hours, cooled naturally, and removed from the kiln for use. This results in aluminum titanate brick molding.

[0045] Example 2

[0046] A1) mixing 45% alumina powder, 35% titanium dioxide, 13% MgCO3, 3% ZnO, and 4% Fe2O3;

[0047] A2) adding water to the mixture obtained in step A1), stirring uniformly, and then filtering to form a cake;

[0048] A3) The cake is passed through a vacuum clay machine to form machine-pressed bricks with a size of 230mm*115mm*65mm;

[0049] A4) The machine-pressed bricks are dried naturally until the moisture content is less than 15%, placed in a high-temperature kiln, baked at 250°C for 3 hours, then heated to 1400°C over 12 hours, kept at this temperature for 2.0 hours, cooled naturally, and removed from the kiln for use to obtain aluminum titanate brick molding materials.

[0050] Example 3

[0051] On the basis of Example 1, the present application uses the aluminum titanate material prepared in Example 1 as a raw material to prepare a ceramic material, specifically comprising the following steps:

[0052] 1) crushing the aluminum titanate brick material prepared in Example 1 into 10 μm to obtain aluminum titanate material;

[0053] 2) 15% kaolin, 70% aluminum titanate prepared in step 1), 10% zirconium silicate, and 5% silicon dioxide were weighed and mixed;

[0054] 3) adding water to the mixture obtained in step 2) and stirring evenly, and then filtering to form a cake;

[0055] 4) The material cake is passed through a vacuum mud kneading machine to form mud strips for later use;

[0056] 5) Place the clay strips into the molded product and dry it naturally in the environment until the moisture content is less than 12%;

[0057] 6) Place the product in a high-temperature kiln, keep it at 100°C for 2 hours, then heat it to 1385°C over 10 hours and keep it at that temperature for 1.2 hours, and naturally cool it to room temperature to obtain aluminum titanate-mullite high thermal shock and high strength ceramic material.

[0058] Comparative Example 1

[0059] The preparation method of the aluminum titanate material provided in this comparative example has the same components and proportions as those in Example 2, except that Fe2O3 is not added. The preparation method is the same as that in Example 2;

[0060] The performance of the aluminum titanate material prepared in Comparative Example 2 was tested, and the results are shown in Table 1.

[0061] Comparative Example 2

[0062] The preparation method of the aluminum titanate material provided in this comparative example has the same components and proportions as those in Example 2, except that ZnO is not added. The preparation method is the same as that in Example 2.

[0063] The performance of the aluminum titanate material prepared in Comparative Example 2 was tested, and the results are shown in Table 1.

[0064] Comparative Example 3

[0065] The preparation method of the aluminum titanate material provided in this comparative example has the same components and proportions as those in Example 2, except that MgCO3 is not added. The preparation method is the same as that in Example 2.

[0066] The performance of the aluminum titanate material prepared in Comparative Example 2 was tested, and the results are shown in Table 1.

[0067] Performance testing:

[0068] 1) Performance test of aluminum titanate material

[0069] The present application conducted a performance test on the aluminum titanate bricks prepared in Example 1 and Example 2, and the results are shown in Table 1:

[0070] Table 1 Performance indexes of aluminum titanate bricks in Example 1-2

[0071] name Expansion coefficient at 20-700℃ Flexural strength / MPa Corrosion resistance Synthesis temperature (℃) Synthesis time (h) Example 1 0.85*10-6 126 51 1400 2h Example 2 0.7*10-6 142 45 1400 2h Comparative Example 1 0.75*10-6 108 43 1480 3.5 Comparative Example 2 0.72*10-6 105 42 1480 3.5 Comparative Example 3 0.81*10-6 96 40 1500 4

[0072] As can be seen from Table 1, the aluminum titanate material provided in the present application, through the comparison of Example 2 with Comparative Example 1, Comparative Example 2 and Comparative Example 3, can be seen that the aluminum titanate material in the present application provides aluminum titanate with high corrosiveness and low expansion main crystal phase through the synergistic effect of MgCO3, ZnO and Fe2O3, combined with the use of Al2O3 and TiO2, which can effectively reduce the reaction temperature and reaction time of the aluminum titanate material. The prepared aluminum titanate material is sintered at a temperature of 1400°C; and the prepared aluminum titanate material sintered body not only has greatly improved mechanical strength, but also does not lose the low thermal expansion coefficient and corrosion resistance inherent in the aluminum titanate sintered body.

[0073] 2) Performance testing of ceramic materials

[0074] The present application conducted a performance test on the ceramic material containing aluminum titanate prepared in Example 3, and the results were as follows:

[0075] name Example 1 Firing temperature / ℃ 1385 Holding time / h 1.2h Water absorption / % 3.5％ Expansion coefficient (20-750℃) <![CDATA[0.82×10 -6 ]]> Flexural strength / MPa 148 Decomposition rate / % 5％ Corrosion resistance times 48

[0076] From the data in Table 2, it can be seen that the ceramic material containing aluminum titanate in the present application has excellent comprehensive properties such as high strength, low water absorption, and high thermal shock resistance.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A method for preparing aluminum titanate material, characterized in that: The steps include: A1) By weight percentage, a mixture is prepared by mixing 40% alumina powder, 35% titanium dioxide, 18% MgCO3, 5% ZnO, and 2% Fe2O3, or 45% alumina powder, 35% titanium dioxide, 13% MgCO3, 3% ZnO, and 4% Fe2O3; A2) Add water to the mixture, stir evenly, and filter press to form a cake; A3) The cakes are made into bricks through a vacuum clay machine and dried for later use; A4) Place the aluminum titanate in a high-temperature kiln and fire it in an oxidizing atmosphere at a temperature of 1400°C for 2 hours to obtain aluminum titanate.

2. A ceramic material containing aluminum titanate prepared by the preparation method according to claim 1, characterized in that: Calculated by mass percentage, the invention comprises the following components: kaolin: 10-20%; aluminum titanate: 65-70%; zirconium silicate: 5-10%; silicon dioxide: 5-15%.

3. The ceramic material according to claim 2, characterized in that The ceramic material is prepared by the following preparation method: B1) mixing kaolin, aluminum titanate, ZrSiO4 and SiO2 according to mass ratio; B2) adding water to the mixture obtained in step B1), stirring uniformly, and then filtering to form a cake; B3) passing the cake through a vacuum mud kneader into mud strips for later use; B4) forming the clay strips into products; B5) The product is fired in a high-temperature kiln and then naturally cooled to room temperature to obtain a ceramic material.

4. The ceramic material according to claim 3, characterized in that The firing conditions are: in an oxidizing atmosphere, the firing temperature is 1400° C., and the firing time is 1-2 hours.