Antioxidant porous TiAl alloy and preparation method and application thereof

Abstract

The invention discloses an antioxidant porous TiAl alloy which comprises the following raw materials: mixed powder, nano B4C, nano NiO and nano SiO2, and the mixed powder comprises TiH2 powder and aluminum powder; in the mixed powder, the content of Ti is 51-53 wt%; the weight ratio of the nano B4C to the nano NiO to the nano SiO2 to the mixed powder is (2-3): (0.5-1.5): (2-3): 100. The invention further discloses a preparation method of the anti-oxidation porous TiAl alloy, and the preparation method comprises the following steps: uniformly mixing TiH2 powder and aluminum powder to obtain mixed powder, then adding nano B4C, nano NiO and nano SiO2, uniformly mixing, carrying out compression molding, carrying out vacuum sintering, soaking in an alkaline solution, and washing with water to obtain the anti-oxidation porous TiAl alloy. The invention also discloses an application of the antioxidant porous TiAl alloy in filtering high-temperature flue gas. The anti-oxidation filtering material has good anti-oxidation performance and filtering performance.

Description

Technical Field

[0001] The present invention relates to the technical field of porous alloys, and in particular to an oxidation-resistant porous TiAl alloy and a preparation method and application thereof. Background Art

[0002] As a new type of material with both functions and structures, porous metal materials have been widely used in the fields of sound absorption, energy absorption, fluid distribution, heat exchange, catalysis, filtration separation, etc., among which filtration separation is the most widely used. Porous metal materials can achieve liquid-solid and gas-solid filtration separation of different fluids in the fields of petroleum, petrochemicals, fine chemicals, coal chemical industry, etc.

[0003] TiAl porous metal is often used as a gas-solid and liquid-solid filter material in high-temperature, corrosive environments; however, in high-temperature oxidative environments, TiAl porous metal will simultaneously generate non-protective TiO 2 With protective Al 2 O 3 mixture, and with non-protective TiO 2 As the main component, this causes the pores of the porous material to be easily blocked, resulting in the failure of the porous metal material. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes an oxidation-resistant porous TiAl alloy and a preparation method and application thereof. The present invention has good high-temperature oxidation resistance and filtering performance.

[0005] The present invention proposes an oxidation-resistant porous TiAl alloy, the raw materials of which include: mixed powder, nano-B 4 C. Nano-NiO, Nano-SiO 2 , wherein the mixed powder includes: TiH 2 powder and aluminum powder;

[0006] In the mixed powder, the Ti content is 51-53wt%;

[0007] Nano B 4 C. Nano-NiO, Nano-SiO 2 The weight ratio of the mixed powder is 2-3:0.5-1.5:2-3:100.

[0008] Preferably, the porosity of the oxidation resistant porous TiAl alloy is 50-52%.

[0009] Preferably, TiH 2 The average particle size of aluminum powder and aluminum powder is 60-80μm.

[0010] Preferably, nano B 4 C. Nano-NiO, Nano-SiO 2The average particle size is 30-50nm.

[0011] The present invention also provides a method for preparing the above-mentioned oxidation-resistant porous TiAl alloy, comprising the following steps: 2 Mix the powder and aluminum powder to obtain a mixed powder, and then add nano B 4 C. Nano-NiO, Nano-SiO 2 The mixture is mixed, pressed into a shape, vacuum sintered, soaked in an alkaline solution, and washed with water to obtain an oxidation-resistant porous TiAl alloy.

[0012] Preferably, the vacuum sintering procedure is: keep at 130-150°C for 0.5-1h, heat to 610-620°C for 2-2.5h, heat to 860-880°C for 3.5-4h, heat to 1300-1320°C for 3.5-4h, and finally cool to room temperature with the furnace.

[0013] Preferably, the alkaline solution is a 0.8-1.2 mol / L sodium hydroxide aqueous solution.

[0014] Preferably, soak at room temperature for 1-2 days.

[0015] The present invention also proposes the use of the above-mentioned oxidation-resistant porous TiAl alloy in filtering high-temperature flue gas.

[0016] Preferably, the invention is used in filtering substances with PM < 2.5 μm in high temperature flue gas.

[0017] The present invention uses TiH 2 The powder and aluminum powder are mixed in a suitable proportion as a mixed powder, and then a suitable vacuum sintering process is adjusted to obtain a TiAl-based porous alloy by powder metallurgy, and an appropriate amount of nano-B is added. 4 C. Nano-NiO, Nano-SiO 2 During vacuum sintering, uniformly distributed TiB can be formed at the grain boundaries in the TiAl alloy structure. 2 Phase and Ti 2 AlC particles can improve the toughness and strength of porous metals; on the other hand, they can form an appropriate amount of Ni 2 Ti 4 O phase, Ti 5 Si 3 The two can cooperate with each other to prevent the diffusion of Ti elements to the metal surface and prevent the diffusion of O elements into the metal, thereby increasing the Al content on the metal surface and avoiding the formation of TiO 2 , and can promote the formation of uniformly distributed nano-Al on the metal surface and inside the pores 2 O 3 , thereby improving the metal's anti-oxidation properties.

[0018] The present invention adjusts appropriate vacuum sintering process parameters so that the metal first forms micropores, and then forms uniformly distributed nano-Al on the metal surface and inside the pores. 2 O 3 Then, it is immersed in an alkaline solution of appropriate concentration for a short time, and the original nano-Al 2 O 3 The nano-Al 2 O 3 The porous layer makes the porous TiAl alloy have micropores and nanopores, which greatly improves the filtration performance of the porous metal, and the nano-Al 2 O 3 The formation of a porous layer can further improve the antioxidant performance.

[0019] And the method of the present invention can avoid nano Al 2 O 3 The porous layer is unevenly distributed, which affects the filtration performance and antioxidant performance. DETAILED DESCRIPTION

[0020] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0021] The formulations of Examples 1-8 are shown in Table 1.

[0022] Table 1 Recipe

[0023] Weight Ratio <![CDATA[Nano B 4 C]]> Nano NiO <![CDATA[Nano SiO 2 > Mixed powder Example 1 3 1.5 2 100 Example 2 2 0.5 3 100 Example 3 2.5 1 2.5 100 Comparative Example 1 / 1 2.5 100 Comparative Example 2 2.5 / 2.5 100 Comparative Example 3 2.5 1 / 100 Comparative Example 4 4 1 2.5 100 Comparative Example 5 1 1 2.5 100 Comparative Example 6 2.5 1 4 100 Comparative Example 7 2.5 1 1 100 Comparative Example 8 2.5 2 2.5 100

[0024] Note: The mixed powder in Table 1 is TiH 2 powder and aluminum powder, and the Ti content is 52wt%, TiH 2 The average particle size of powder and aluminum powder is 60μm; nano B 4 C. Nano-NiO, Nano-SiO 2 The average particle size is 40 nm.

[0025] According to the various formulas in Table 1, the same method was used to prepare oxidation-resistant porous TiAl alloys. The preparation method includes the following steps: taking TiH 2 The powder and aluminum powder were ball-milled to obtain a mixed powder, and then nano-B4C, nano-NiO, nano-SiO 2The mixture was ball-milled and mixed, and then the pressure was adjusted to 200 MPa for compression molding, and the mixture was transferred to a heating furnace, and the vacuum degree was adjusted to 0.005 Pa for vacuum sintering. The vacuum sintering procedure was as follows: keep warm at 140°C for 0.8 h, increase the temperature to 620°C at a rate of 5°C / min and keep warm for 2 h, then increase the temperature to 880°C at a rate of 5°C / min and keep warm for 4 h, then increase the temperature to 1320°C at a rate of 5°C / min and keep warm for 4 h, and finally cool to room temperature with the furnace; then add it to a 1 mol / L sodium hydroxide aqueous solution, soak it at room temperature for 2 days, wash it with water, and dry it to obtain an oxidation-resistant porous TiAl alloy.

[0026] Comparative Example 9

[0027] The oxidation-resistant porous TiAl alloy was prepared according to the recipe of Example 3, but was not immersed in a sodium hydroxide aqueous solution.

[0028] The oxidation resistant porous TiAl alloys prepared in each group were taken for performance testing, and the results are shown in Table 2.

[0029] The detection method of oxidation weight gain is: place each group of samples in an air environment at 900°C, keep warm for 100 hours, then take them out and cool for 3 hours, and calculate the weight gain of each group of samples.

[0030] Table 2 Test results

[0031]

[0032]

[0033] It can be seen from Table 2 that nano B 4 C. Nano-NiO and Nano-SiO 2 The porous TiAl alloy with good antioxidant and filtration properties can be obtained after the three are combined and soaked in sodium hydroxide aqueous solution. 4 C. Nano-NiO and Nano-SiO 2 When the dosage is too high or too low, its high-temperature antioxidant performance and high-temperature flue gas filtration performance of PM<2.5μm will be reduced.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An oxidation-resistant porous TiAl alloy, characterized in that: The raw materials include: mixed powder, nano B4C, nano NiO, nano SiO2, wherein the mixed powder includes: TiH2 powder and aluminum powder; In the mixed powder, the Ti content is 51-53wt%; The weight ratio of nano B4C, nano NiO, nano SiO2 and mixed powder is 2-3:0.5-1.5:2-3:

100.

2. The oxidation-resistant porous TiAl alloy according to claim 1, characterized in that: The porosity of the oxidation resistant porous TiAl alloy is 50-52%.

3. The oxidation-resistant porous TiAl alloy according to claim 1 or 2, characterized in that: The average particle size of TiH2 powder and aluminum powder is 60-80 μm.

4. The oxidation-resistant porous TiAl alloy according to any one of claims 1 to 3, characterized in that: The average particle size of nano-B4C, nano-NiO and nano-SiO2 is 30-50nm.

5. A method for preparing the oxidation-resistant porous TiAl alloy according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: mixing TiH2 powder and aluminum powder to obtain mixed powder, then adding nano B4C, nano NiO and nano SiO2 to mix, pressing and molding, vacuum sintering, soaking in alkaline solution, washing with water to obtain oxidation-resistant porous TiAl alloy.

6. The method for preparing the oxidation-resistant porous TiAl alloy according to claim 5, characterized in that: The vacuum sintering procedure is: keep at 130-150℃ for 0.5-1h, heat to 610-620℃ for 2-2.5h, heat to 860-880℃ for 3.5-4h, heat to 1300-1320℃ for 3.5-4h, and finally cool to room temperature with the furnace.

7. The method for preparing the oxidation-resistant porous TiAl alloy according to claim 5 or 6, characterized in that: The alkaline solution is a 0.8-1.2 mol / L sodium hydroxide aqueous solution.

8. The method for preparing the oxidation-resistant porous TiAl alloy according to any one of claims 5 to 7, characterized in that: Soak at room temperature for 1-2 days.

9. Use of the oxidation-resistant porous TiAl alloy according to any one of claims 1 to 4 in filtering high-temperature flue gas.

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