In-situ synthesis method of Al2O3-TiN composite material

Abstract

The invention discloses an in-situ synthesis method of an Al2O3-TiN composite material, which comprises the following steps of: adding absolute ethyl alcohol into a planetary ball mill according to a certain weight percentage of byproducts of high-aluminum titanium slag and aluminum powder for smelting iron-titanium alloy, uniformly mixing, and drying at the temperature of between 80 and 120 DEG C; a binding agent is added to the dried mixture, and forming is conducted under the pressure of 150-250 MPa; and putting the molded mixture into a furnace, heating and preserving heat under a carbon burying condition, naturally cooling, taking out from the furnace, and removing a surface impurity layer to obtain the Al2O3-TiN composite material. The method overcomes the defects of traditional Al2O3-TiN composite material preparation, has the characteristics of cheap raw materials, low synthesis temperature and simple process, and is beneficial to industrial production and application.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic material synthesis and preparation, in particular to an in-situ synthesis method of an Al2O3-TiN composite material. Background Art

[0002] Al2O3-based ceramics possess excellent physical and chemical properties, including high hardness, wear resistance, good chemical stability, and low cost. They are widely used in electronics, chemical engineering, machinery, metallurgy, and other fields. However, their inherent brittleness hinders their practical application in engineering. Therefore, addressing the low strength and fracture toughness of individual Al2O3 ceramic materials has become a hot topic for researchers both domestically and internationally.

[0003] There are many methods for toughening Al2O3 ceramics, among which particle dispersion toughening is an effective method. This involves adding second-phase particles to Al2O3 to significantly enhance its toughness. TiN is a new multifunctional material with advantages such as a high melting point, high chemical stability, and high hardness. Introducing TiN particles into the Al2O3 matrix not only improves its strength, toughness, and wear resistance, but also enhances its electrical conductivity, enabling its use in the manufacture of high-temperature heating devices, ignition devices, and high-temperature wear-resistant components. Consequently, Al2O3-TiN composites have attracted widespread attention in the materials community in recent years due to their excellent performance.

[0004] The more traditional Al2O3-TiN composite method involves mechanically mixing Al2O3 powder with TiN powder, forming it, and then sintering it. This method, on the one hand, increases manufacturing costs due to the high price of TiN and the high sintering temperature required. On the other hand, it can easily cause the added phase to agglomerate or lead to component segregation, ultimately resulting in a decrease in the mechanical and electrical properties of the composite material. In-situ synthesis technology replaces TiN with less expensive Ti powder or TiO2 powder, reducing raw material costs while effectively reducing microstructural heterogeneity in the composite material. It also has the potential to synthesize composite materials with fine, even nanoscale, grains, thereby addressing the brittleness of ceramic materials. However, this method uses N2 as the firing atmosphere for nitriding during the firing process, which is a complex process and can easily lead to incomplete reaction of material components and high firing temperatures. Furthermore, it still uses high-purity raw materials such as Al2O3, resulting in high production costs, high prices, and difficulty in industrial production. It can be seen that how to prepare Al2O3-TiN composite materials with excellent performance using simple and feasible processes and low-cost raw materials, so as to facilitate their large-scale production and application, has become the focus of research on this type of materials. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an in-situ synthesis method of Al2O3-TiN composite material. This method overcomes the defects of traditional Al2O3-TiN composite material preparation, has the characteristics of cheap raw materials, low synthesis temperature and simple process, and is conducive to industrial production and application.

[0006] To solve the above technical problems, the in-situ synthesis method of the Al2O3-TiN composite material of the present invention comprises the following steps: Step 1: 80-94% by weight of high-aluminum titanium slag, a by-product of ferro-titanium alloy smelting, and 20-6% of aluminum powder are mixed evenly with anhydrous ethanol in a planetary ball mill, and then dried at 80-120° C.; Step 2: Add 0-7% binder to the dried mixture and form it under a pressure of 150-250 MPa; Step 3: The formed mixture is placed in a furnace under carbon buried conditions, heated at 1350-1550° C. and kept warm for 3-6 hours. After natural cooling, the mixture is taken out of the furnace and the surface impurity layer is removed to obtain an Al 2 O 3 -TiN composite material.

[0007] Furthermore, the particle size of the high-aluminum titanium slag and the aluminum powder is less than 0.088 mm, the components of the high-aluminum titanium slag are Al2O3 and Ti2O3, and Al2O3 and Ti2O3 each exist in the form of an independent phase, and the aluminum powder is flaky aluminum powder or spherical aluminum powder.

[0008] Furthermore, the carbon embedding condition is to embed the formed mixture in a corundum sagger filled with coke powder, and then put the corundum sagger into a furnace for heating and heat preservation.

[0009] Furthermore, the binder accounts for 0 to 5% of the weight of the dried mixture.

[0010] Furthermore, the binder is phenolic resin. The in-situ synthesis method of the Al2O3-TiN composite material of the present invention adopts the above-mentioned technical scheme, namely, the method comprises uniformly mixing a certain amount of high-aluminum titanium slag, a byproduct of ferro-titanium alloy smelting, and aluminum powder in a planetary ball mill with anhydrous ethanol according to weight percentage, and then drying the mixture at 80-120°C; adding a binder to the dried mixture and forming it under a pressure of 150-250 MPa; placing the formed mixture in a furnace under carbon-buried conditions, heating and maintaining the heat, and after natural cooling, removing it from the furnace and removing the surface impurity layer to obtain the Al2O3-TiN composite material. This method overcomes the shortcomings of traditional Al2O3-TiN composite material preparation, has the advantages of cheap raw materials, low synthesis temperature, and simple process, and is conducive to industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments: Figure 1 Schematic diagram of XRD of Al2O3-TiN composite material synthesized by this method. DETAILED DESCRIPTION

[0012] The in-situ synthesis method of the Al2O3-TiN composite material of the present invention comprises the following steps: Step 1: 80-94% by weight of high-aluminum titanium slag, a by-product of ferro-titanium alloy smelting, and 20-6% of aluminum powder are mixed evenly with anhydrous ethanol in a planetary ball mill, and then dried at 80-120° C.; Step 2: Add 0-7% binder to the dried mixture and form it under a pressure of 150-250 MPa; Step 3: The formed mixture is placed in a furnace under carbon buried conditions, heated at 1350-1550° C. and kept warm for 3-6 hours. After natural cooling, the mixture is taken out of the furnace and the surface impurity layer is removed to obtain an Al 2 O 3 -TiN composite material.

[0013] Preferably, the particle size of the high-aluminum titanium slag and the aluminum powder is less than 0.088 mm, the components of the high-aluminum titanium slag are Al2O3 and Ti2O3, and Al2O3 and Ti2O3 each exist in the form of an independent phase, and the aluminum powder is flaky aluminum powder or spherical aluminum powder.

[0014] Preferably, the carbon embedding condition is to embed the formed mixture in a corundum sagger filled with coke powder, and then place the corundum sagger in a furnace for heating and heat preservation.

[0015] Preferably, the binder accounts for 0-5% of the weight of the dried mixed material.

[0016] Preferably, the binder is phenolic resin.

[0017] This method is specifically implemented as follows: Example 1 80% high-aluminum titanium slag and 20% spherical aluminum powder were weighed and prepared according to their mass percentages, and anhydrous ethanol was added until the materials were immersed. The mixture was thoroughly mixed on a planetary ball mill, and the obtained mixture was dried at 90°C. The dried mixture was pressed into shape under a pressure of 150 MPa, and then the sample was buried in a corundum sagger filled with coke powder. The corundum sagger was then placed in a furnace under carbon-buried conditions, heated at 1400°C and kept warm for 4 hours. After natural cooling, the sample was removed from the corundum sagger and the carbon impurity layer on the surface was removed to obtain an Al2O3-TiN composite material.

[0018] Example 2 94% high-aluminum titanium slag and 6% spherical aluminum powder were weighed and prepared according to their mass percentages, anhydrous ethanol was added until the materials were immersed, and the mixture was thoroughly mixed on a planetary ball mill. The resulting mixture was dried at 90°C; 3wt% phenolic resin of the dried mixture was added as a binder, mixed for 35 minutes, pressed into shape under a pressure of 200MPa, and dried at 180°C for 10 hours. The sample was then buried in a corundum sagger filled with coke powder, and the corundum sagger was placed in a furnace under carbon-buried conditions, heated at 1450°C and kept warm for 3.5 hours. After natural cooling, the sample was removed from the corundum sagger and the carbon impurity layer on the surface was removed to obtain an Al2O3-TiN composite material.

[0019] Example 3 85% high-aluminum titanium slag and 15% flaky aluminum powder were weighed and prepared according to their mass percentages, anhydrous ethanol was added until the materials were immersed, and the mixture was thoroughly mixed on a planetary ball mill. The obtained mixture was dried at 90°C; the dried mixture was pressed into shape under a pressure of 150 MPa, and then the sample was buried in a corundum sagger filled with coke powder. The corundum sagger was then placed in a furnace under carbon-buried conditions, heated at 1400°C and kept warm for 4 hours. After natural cooling, the sample was removed from the corundum sagger and the carbon impurity layer on the surface was removed to obtain an Al2O3-TiN composite material.

[0020] The particle size of the raw materials in the above examples is less than 0.088 mm. The experimental methods are all conventional methods, and the reagents and materials can be obtained from commercial channels.

[0021] like Figure 1 As shown in the figure, at 1350°C, the titanium-containing phase in the raw material of the Al2O3-TiN composite material prepared by this method has been completely transformed into TiN, and a small amount of magnesia-alumina spinel in the sample is the reaction product of Al2O3 in the raw material and the impurity MgO. Figure 1 The horizontal axis represents the angle at which the diffraction peak appears, and the vertical axis represents the diffraction intensity.

[0022] The advantages of this method are: 1. Using high-aluminum titanium slag and aluminum powder as raw materials, Al2O3-TiN composite materials are synthesized by aluminothermic reduction reaction in a carbon-buried atmosphere. There is no need to use high-purity raw materials and N2 atmosphere. The raw materials are cheap, the synthesis temperature is low, and the process is simple.

[0023] 2. During the synthesis of the Al2O3-TiN composite material, an aluminothermic reduction method is used in a carbon-buried atmosphere. The furnace atmosphere can be approximately assumed to have a nitrogen partial pressure of 0.65 and a carbon monoxide partial pressure of 0.35. During the heat treatment process, the titanium oxides in the high-aluminum titanium slag undergo an aluminothermic reduction reaction with the aluminum powder to produce aluminum oxide and metallic titanium. The metallic titanium then reacts with the nitrogen in the atmosphere to produce AlN, thus forming the Al2O3-TiN composite material.

[0024] Since the titanium oxide in the high-aluminum titanium slag exists in the form of low-valent titanium Ti2O3, it is more likely to undergo aluminothermic reduction reaction, and the Al2O3 generated in situ by the aluminothermic reaction is highly active, which is conducive to the densification of the material. In addition, the aluminothermic reduction reaction is an exothermic reaction and releases a large amount of heat. This heat will make the actual temperature of the sample higher than the temperature in the furnace. Therefore, the temperature of the Al2O3-TiN composite material synthesized by this method is relatively low. It can be seen that this method has the characteristics of simple process, low synthesis temperature, low production cost and easy industrial production. The Al2O3-TiN composite material prepared by this method can be used as a matrix component of ceramic products, and can also be introduced into refractory materials as an additive to improve its resistance to slag erosion and other properties.

Claims

1. An in-situ synthesis method of Al2O3-TiN composite material, characterized in that The steps include: Step 1: 80-94% by weight of high-aluminum titanium slag, a by-product of ferro-titanium alloy smelting, and 20-6% of aluminum powder are mixed evenly with anhydrous ethanol in a planetary ball mill, and then dried at 80-120° C.; Step 2: Add 0-7% binder to the dried mixture and form it under a pressure of 150-250 MPa; Step 3: The formed mixture is placed in a furnace under carbon buried conditions, heated at 1350-1550° C. and kept warm for 3-6 hours. After natural cooling, the mixture is taken out of the furnace and the surface impurity layer is removed to obtain an Al 2 O 3 -TiN composite material.

2. The in-situ synthesis method of the Al2O3-TiN composite material according to claim 1, characterized in that: The particle size of the high-aluminum titanium slag and the aluminum powder is less than 0.088 mm. The components of the high-aluminum titanium slag are Al2O3 and Ti2O3, and Al2O3 and Ti2O3 each exist in the form of an independent phase. The aluminum powder is flaky aluminum powder or spherical aluminum powder.

3. The in-situ synthesis method of the Al2O3-TiN composite material according to claim 1 or 2, characterized in that: The carbon embedding condition is to embed the formed mixed material in a corundum sagger filled with coke powder, and then put the corundum sagger into a furnace for heating and heat preservation.

4. The in-situ synthesis method of the Al2O3-TiN composite material according to claim 3, characterized in that: The binder accounts for 0-5% of the weight of the dried mixed material.

5. The in-situ synthesis method of the Al2O3-TiN composite material according to claim 4, characterized in that: The binder is phenolic resin.

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