High-strength erosion-resistant al4o4c-based composite material and method for preparing the same

Abstract

The application relates to a high-strength erosion-resistant Al4O4C-based composite material and a preparation method thereof. The technical scheme is as follows: part of a tempering agent is added into carbon aluminum oxide powder, mixed, and then the rest of the tempering agent and yttrium oxide powder are added to obtain mixed powder. The mixed powder, anhydrous ethanol and ball milling beads are placed in a ball mill to obtain mixed slurry; the mixed slurry is dried and ground to obtain ground material; the ground material and a binding agent are mixed, pre-pressed and cold isostatic pressed to obtain a composite material preform; then drying and curing are carried out, glue removal is carried out in an atmosphere protection furnace, finally, the obtained composite material blank is placed in a graphite crucible and placed in a high-temperature atmosphere sintering furnace to be heated, kept and cooled to obtain the high-strength erosion-resistant Al4O4C-based composite material. The high-strength erosion-resistant Al4O4C-based composite material prepared by the application has the characteristics of excellent erosion resistance and good mechanical properties, and can meet the requirements of materials for preparing crucibles for vacuum induction melting high-temperature alloys.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature structural ceramics technology. Specifically, it relates to a high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. Background Technology

[0002] In recent years, the development of science and technology has demanded increasingly higher material performance, especially given the critical core technologies that urgently need to be addressed under the current international situation. This places even higher demands on crucible materials for vacuum induction melting of high-temperature alloys. During high-temperature use, to prevent the crucible material from reacting with the alloy and to improve the alloy's purity, crucible materials for high-temperature alloy melting should possess excellent corrosion resistance; simultaneously, they should also have excellent mechanical properties. Al4O4C is considered the most stable compound in the Al-OC system (Yu C, Dong B, Chen Y, et al. Enhanced oxidation resistance of low-carbon MgO–C refractories with ternary carbides: a review[J]. Journal of Iron and Steel Research International, 2022, 29(7): 1052-1062.), and due to its low density (2.68 g·cm³), it is highly suitable for high-temperature alloys. -3 Al4O4C-based composites have attracted increasing attention due to their high melting point (~1890℃), good resistance to hydration and oxidation, and efficient luminescence properties, and are expected to be widely used in the field of high-temperature alloy melting crucibles. However, the mechanical properties and corrosion resistance of Al4O4C-based composites still face significant challenges.

[0003] Yu et al. (Yu C, Cheng K, Ding J, et al. Synthesis and some properties of Al4SiC4–Al4O4C composites[J]. Ceramics International, 2018, 44(14): 17154–17159.) studied the effects of synthesis temperature and raw material ratio on the formation process and corrosion resistance of Al4SiC4–Al4O4C composites. As corrosion progressed, a layer of calcium hexaaluminate (CA6) was formed on the hot surface of the Al4SiC4–Al4O4C composite, which reduced the slag erosion rate. However, the Al4O4C-based composite prepared by this technology had poor density and was easily eroded and penetrated by slag, thus leading to a decrease in its corrosion resistance.

[0004] Yan et al. (Yan M, Zhang J, Sun G, et al. RETRACTED: Phase composition, microstructure, and properties ofAl4O4C–(Al2OC) 1-x (AlN) x (Zr2Al3C4–Al2O3refractories prepared at high temperatures in nitrogen[J].2021.) A novel ultra-low carbon Al4O4C–(Al2OC) was prepared by constructing an Al@AlN+C core-shell structure at 1300–1700 °C in nitrogen. 1-x (AlN) x –Zr2Al3C4–Al2O3 composite material, however, ZrO2 with poor crystal stability will appear during the preparation process. Its crystal transformation will cause a large volume expansion, which weakens the mechanical properties of the composite material. Summary of the Invention

[0005] The present invention aims to overcome the defects of the prior art and provides a method for preparing a high-strength and corrosion-resistant Al4O4C-based composite material. The products prepared by this method have excellent corrosion resistance and good mechanical properties, and can meet the material requirements for crucibles used in the preparation of high-temperature alloys by vacuum induction melting.

[0006] To achieve the above objectives, the technical solution steps adopted by the present invention are as follows:

[0007] Step 1: Prepare a mixture of 55-80 wt% alumina powder, 10-30 wt% yttrium oxide powder, and 5-20 wt% conditioning agent. First, add 40-60 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0008] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:6 to 8:3 to 6. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill at 150 to 300 r / min for 8 to 16 hours to obtain a mixed slurry.

[0009] Step 3: Dry the mixed slurry at 60-110℃ for 24-48 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0010] Step 4: Mix the abrasive and the binder according to the mass ratio of abrasive to binder of 1:0.05 to 0.2, place them in a pre-pressing mold, pre-press under molding conditions of 10 to 20 MPa, and then cold isostatically press under conditions of 100 to 200 MPa to obtain the composite material preform.

[0011] Step 5: Dry the composite preform at 60-110℃ for 24-48 hours, then cure it at 110-250℃ for 4-18 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0012] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1600-1800℃ at a rate of 5-30℃ / min, hold for 60-180min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0013] The Al4O4C content of the alumina powder is ≥99.9wt%; the particle size of the alumina powder is less than 20μm.

[0014] The yttrium oxide powder has a Y2O3 content ≥ 99.5 wt% and a particle size of less than 6 μm.

[0015] The conditioning agent is one of aluminum powder, alumina powder, and corundum powder, wherein: the aluminum powder has an Al content ≥99wt%, the alumina powder has an Al2O3 content ≥99wt%, and the corundum powder has an Al2O3 content ≥98wt%; the particle size of the conditioning agent is less than 75μm.

[0016] The binder is one of epoxy resin, phenolic resin and polyvinyl alcohol.

[0017] The ball mill is either a horizontal ball mill or a planetary ball mill.

[0018] The grinding beads are made of agate or zirconium oxide.

[0019] The purity of the argon atmosphere is 99.99%; the flow rate is 15-20 L / min.

[0020] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0021] This invention uses alumina powder and yttrium oxide powder as raw materials, and adds conditioning agents and binders to mix them. During the sintering process, the alumina powder decomposes at high temperature and reacts with yttrium oxide to generate Y3Al5O with a uniform structure in situ. 12 The network structure allows for the in-situ formation of Y3Al5O at high temperatures.12 It exhibits good interphase compatibility and tight bonding with the Al4O4C matrix material, and the in-situ generated Y3Al5O 12 The grains can directly fill the pores between Al4O4C grains, effectively promoting the growth of Y3Al5O 12 - The compactness of Al4O4C composite materials. In Y3Al5O 12 The Al4O4C structure and its high density effectively prevent further penetration of the titanium liquid, resulting in a high-strength, corrosion-resistant Al4O4C-based composite material with excellent corrosion resistance.

[0022] The high-strength, corrosion-resistant Al4O4C-based composite material prepared by this invention utilizes an in-situ formed yttrium aluminate liquid phase to promote anisotropic grain growth of Al4O4C, which then solidifies at the Al4O4C grain boundaries in the form of a YAG phase. During the consolidation shrinkage process, the high thermal expansion coefficient of the yttrium aluminate liquid phase contributes to the growth of Y3Al5O4C. 12 - Compressive stress is generated at the grain boundaries of Al4O4C, thereby strengthening the grain boundaries and improving the mechanical properties of high-strength and corrosion-resistant Al4O4C-based composite materials.

[0023] The high-strength, corrosion-resistant Al4O4C-based composite material prepared by this invention was tested and found to have a flexural strength of 118–331 MPa and a fracture toughness of 6.1–8.9 MPa·m. 1 / 2 The Vickers hardness is 10.4–18.9 GPa; the wetting angle is 75–90°.

[0024] Therefore, the high-strength, corrosion-resistant Al4O4C-based composite material prepared by this invention has excellent corrosion resistance and good mechanical properties, and can meet the material requirements for crucibles used in the preparation of high-temperature alloys by vacuum induction melting. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the scope of protection thereof.

[0026] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The preparation method described in this specific embodiment includes the following steps:

[0027] Step 1: Prepare a mixture of 55-80 wt% alumina powder, 10-30 wt% yttrium oxide powder, and 5-20 wt% conditioning agent. First, add 40-60 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0028] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:6 to 8:3 to 6. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill at 150 to 300 r / min for 8 to 16 hours to obtain a mixed slurry.

[0029] Step 3: Dry the mixed slurry at 60-110℃ for 24-48 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0030] Step 4: Mix the abrasive and the binder according to the mass ratio of abrasive to binder of 1:0.05 to 0.2, place them in a pre-pressing mold, pre-press under molding conditions of 10 to 20 MPa, and then cold isostatically press under conditions of 100 to 200 MPa to obtain the composite material preform.

[0031] Step 5: Dry the composite preform at 60-110℃ for 24-48 hours, then cure it at 110-250℃ for 4-18 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0032] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1600-1800℃ at a rate of 5-30℃ / min, hold for 60-180min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0033] The conditioning agent is one of aluminum powder, alumina powder, and corundum powder.

[0034] The binder is one of epoxy resin, phenolic resin and polyvinyl alcohol.

[0035] The ball mill is either a horizontal ball mill or a planetary ball mill.

[0036] The grinding beads are made of agate or zirconium oxide.

[0037] The flow rate of the argon gas is 15-20 L / min.

[0038] In this specific implementation:

[0039] The Al4O4C content of the alumina powder is ≥99.9wt%; the particle size of the alumina powder is less than 20μm.

[0040] The yttrium oxide powder has a Y2O3 content ≥ 99.5 wt% and a particle size of less than 6 μm.

[0041] The conditioning agent contains: aluminum powder with an Al content ≥ 99 wt%, alumina powder with an Al2O3 content ≥ 99 wt%, and corundum powder with an Al2O3 content ≥ 98 wt%; the particle size of the conditioning agent is less than 75 μm.

[0042] The purity of the argon atmosphere is 99.99%.

[0043] The details will not be repeated in the examples.

[0044] Example 1

[0045] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The steps of the preparation method described in this embodiment are as follows:

[0046] Step 1: Prepare a mixture of 55 wt% alumina powder, 30 wt% yttrium oxide powder, and 15 wt% conditioning agent. First, add 60 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0047] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:8:6. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill for 16 hours at 300 r / min to obtain a mixed slurry.

[0048] Step 3: Dry the mixed slurry at 110°C for 48 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0049] Step 4: Mix the abrasive and binder according to the mass ratio of 1:0.2, place them in a pre-pressing mold, pre-press under molding conditions of 20MPa, and then cold isostatically press under conditions of 200MPa to obtain the composite material preform.

[0050] Step 5: Dry the composite preform at 110°C for 48 hours, then cure it at 250°C for 18 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0051] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1800℃ at a rate of 30℃ / min, hold for 60min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0052] The conditioning agent is corundum powder.

[0053] The binder is epoxy resin.

[0054] The ball mill is a horizontal ball mill.

[0055] The grinding beads are made of agate.

[0056] The flow rate of the argon gas is 15 L / min.

[0057] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this embodiment was tested and found to have a flexural strength of 118 MPa and a fracture toughness of 6.1 MPa·m. 1 / 2 The Vickers hardness is 10.4 GPa; the wetting angle is 80°.

[0058] Example 2

[0059] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The steps of the preparation method described in this embodiment are as follows:

[0060] Step 1: Prepare a mixture of 60 wt% alumina powder, 20 wt% yttrium oxide powder, and 20 wt% conditioning agent. First, add 55 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0061] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:8:5. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill for 8 hours at 200 r / min to obtain a mixed slurry.

[0062] Step 3: Dry the mixed slurry at 100°C for 36 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0063] Step 4: Mix the abrasive and binder according to the mass ratio of 1:0.15, place them in a pre-pressing mold, pre-press under molding conditions of 18MPa, and then cold isostatically press under conditions of 180MPa to obtain the composite material preform.

[0064] Step 5: Dry the composite preform at 100°C for 36 hours, then cure it at 190°C for 15 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0065] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1780℃ at a rate of 25℃ / min, hold for 100min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0066] The conditioning agent is corundum powder.

[0067] The binder is epoxy resin.

[0068] The ball mill is a planetary ball mill.

[0069] The grinding beads are made of agate.

[0070] The flow rate of the argon gas is 16 L / min.

[0071] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this embodiment was tested and found to have a flexural strength of 245 MPa and a fracture toughness of 7.9 MPa·m. 1 / 2 The Vickers hardness is 14.3 GPa; the wetting angle is 75°.

[0072] Example 3

[0073] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The steps of the preparation method described in this embodiment are as follows:

[0074] Step 1: Prepare a mixture of 65 wt% alumina powder, 25 wt% yttrium oxide powder, and 10 wt% conditioning agent. First, add 50 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0075] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:7:4. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill for 16 hours at 250 r / min to obtain a mixed slurry.

[0076] Step 3: Dry the mixed slurry at 90°C for 24 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0077] Step 4: Mix the abrasive and binder according to the mass ratio of 1:0.1, place them in a pre-pressing mold, pre-press under molding conditions of 17MPa, and then cold isostatically press under conditions of 160MPa to obtain the composite material preform.

[0078] Step 5: Dry the composite preform at 90°C for 24 hours, then cure it at 170°C for 12 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0079] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1750℃ at a rate of 20℃ / min, hold for 120min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0080] The conditioning agent is aluminum powder.

[0081] The binder is phenolic resin.

[0082] The ball mill is a horizontal ball mill.

[0083] The grinding beads are made of zirconium oxide.

[0084] The flow rate of the argon gas is 17 L / min.

[0085] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this embodiment was tested and found to have a flexural strength of 331 MPa and a fracture toughness of 8.9 MPa·m. 1 / 2 The Vickers hardness is 18.9 GPa; the wetting angle is 85°.

[0086] Example 4

[0087] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The steps of the preparation method described in this embodiment are as follows:

[0088] Step 1: Prepare a mixture of 70 wt% alumina powder, 15 wt% yttrium oxide powder, and 15 wt% conditioning agent. First, add 45 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0089] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:7:3. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill for 12 hours at 280 r / min to obtain a mixed slurry.

[0090] Step 3: Dry the mixed slurry at 80°C for 48 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0091] Step 4: Mix the abrasive and binder according to the mass ratio of 1:0.05, place them in a pre-pressing mold, pre-press under a molding condition of 15MPa, and then cold isostatically press under a condition of 150MPa to obtain the composite material preform.

[0092] Step 5: Dry the composite preform at 80°C for 48 hours, then cure it at 150°C for 10 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0093] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1700℃ at a rate of 15℃ / min, hold for 150min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0094] The conditioning agent is aluminum powder.

[0095] The binder is phenolic resin.

[0096] The ball mill is a planetary ball mill.

[0097] The grinding beads are made of zirconium oxide.

[0098] The flow rate of the argon gas is 18 L / min.

[0099] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this embodiment was tested and found to have a flexural strength of 315 MPa and a fracture toughness of 7.2 MPa·m. 1 / 2 The Vickers hardness is 16.1 GPa; the wetting angle is 88°.

[0100] Example 5

[0101] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The steps of the preparation method described in this embodiment are as follows:

[0102] Step 1: Prepare a mixture of 75 wt% alumina powder, 10 wt% yttrium oxide powder, and 15 wt% conditioning agent. First, add 43 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0103] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:6:3. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill for 16 hours at 180 r / min to obtain a mixed slurry.

[0104] Step 3: Dry the mixed slurry at 70°C for 36 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0105] Step 4: Mix the abrasive and binder according to the mass ratio of 1:0.18, place them in a pre-pressing mold, pre-press under molding conditions of 13MPa, and then cold isostatically press under conditions of 120MPa to obtain the composite material preform.

[0106] Step 5: Dry the composite preform at 70°C for 36 hours, then cure it at 130°C for 8 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0107] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1650℃ at a rate of 10℃ / min, hold for 170min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0108] The conditioning agent is alumina powder.

[0109] The binder is polyvinyl alcohol.

[0110] The ball mill is a horizontal ball mill.

[0111] The grinding beads are made of agate.

[0112] The flow rate of the argon gas is 19 L / min.

[0113] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this embodiment was tested and found to have a flexural strength of 297 MPa and a fracture toughness of 7.1 MPa·m. 1 / 2 The Vickers hardness is 16.8 GPa; the wetting angle is 81°.

[0114] Example 6

[0115] A high-strength, corrosion-resistant Al4O4C-based composite material and its preparation method. The steps of the preparation method described in this embodiment are as follows:

[0116] Step 1: Prepare a mixture of 80 wt% alumina powder, 15 wt% yttrium oxide powder, and 5 wt% conditioning agent. First, add 40 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder.

[0117] Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:6:6. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill at 150 r / min for 8 hours to obtain a mixed slurry.

[0118] Step 3: Dry the mixed slurry at 60°C for 24 hours to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material.

[0119] Step 4: Mix the abrasive and binder according to the mass ratio of 1:0.08, place them in a pre-pressing mold, pre-press under a molding condition of 10MPa, and then cold isostatically press under a condition of 100MPa to obtain the composite material preform.

[0120] Step 5: Dry the composite preform at 60°C for 24 hours, then cure it at 110°C for 4 hours. Place the cured composite preform in an atmosphere-protected furnace and remove the adhesive in an argon atmosphere to obtain the raw composite preform.

[0121] Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1600℃ at a rate of 5℃ / min, hold for 180min, and cool with the furnace to obtain a high-strength, corrosion-resistant Al4O4C-based composite material.

[0122] The conditioning agent is alumina powder.

[0123] The binder is polyvinyl alcohol.

[0124] The ball mill is a planetary ball mill.

[0125] The grinding beads are made of zirconium oxide.

[0126] The flow rate of the argon gas is 20 L / min.

[0127] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this embodiment was tested and found to have a flexural strength of 323 MPa and a fracture toughness of 8.1 MPa·m. 1 / 2 The Vickers hardness is 18.2 GPa; the wetting angle is 90°.

[0128] This specific implementation method has the following advantages compared with the prior art:

[0129] This specific embodiment uses alumina powder and yttrium oxide powder as raw materials, and adds a conditioning agent and binder to mix them. During the sintering process, the alumina powder decomposes at high temperature and reacts with yttrium oxide to generate Y3Al5O in situ with a uniform structure. 12 The network structure allows for the in-situ formation of Y3Al5O at high temperatures. 12 It exhibits good interphase compatibility and tight bonding with the Al4O4C matrix material, and the in-situ generated Y3Al5O 12 The grains can directly fill the pores between Al4O4C grains, effectively promoting the growth of Y3Al5O12 - The compactness of Al4O4C composite materials. In Y3Al5O 12 The Al4O4C structure and its high density effectively prevent further penetration of the titanium liquid, resulting in a high-strength, corrosion-resistant Al4O4C-based composite material with excellent corrosion resistance.

[0130] The high-strength, corrosion-resistant Al4O4C-based composite material prepared in this specific embodiment utilizes an in-situ formed yttrium aluminate liquid phase, which promotes the anisotropic grain growth of Al4O4C and solidifies at the Al4O4C grain boundaries in the form of a YAG phase. During the consolidation shrinkage process, the high thermal expansion coefficient of the yttrium aluminate liquid phase contributes to the growth of Y3Al5O4C. 12 - Compressive stress is generated at the grain boundaries of Al4O4C, thereby strengthening the grain boundaries and improving the mechanical properties of high-strength and corrosion-resistant Al4O4C-based composite materials.

[0131] The high-strength, corrosion-resistant Al4O4C-based composite material prepared according to this specific embodiment was tested and found to have a flexural strength of 118–331 MPa and a fracture toughness of 6.1–8.9 MPa·m. 1 / 2 The Vickers hardness is 10.4–18.9 GPa; the wetting angle is 75–90°.

[0132] Therefore, the high-strength, corrosion-resistant Al4O4C-based composite material prepared in this specific embodiment has excellent corrosion resistance and good mechanical properties, and can meet the material requirements for crucibles used in the preparation of high-temperature alloys by vacuum induction melting.

Claims

1. A method for preparing a high-strength, corrosion-resistant Al4O4C-based composite material, characterized in that, The preparation method comprises the following steps: Step 1: Prepare a mixture of 55-80 wt% alumina powder, 10-30 wt% yttrium oxide powder, and 5-20 wt% conditioning agent. First, add 40-60 wt% of the conditioning agent to the alumina powder and mix. Then, add the remaining yttrium oxide powder and the conditioning agent in sequence to obtain a mixed powder. The conditioning agent is one of aluminum powder, alumina powder and corundum powder, and the particle size of the conditioning agent is less than 75 μm; Step 2: Prepare the mixture according to the mass ratio of the mixed powder: anhydrous ethanol: milling beads of 1:6~8:3~6. Place the mixed powder, anhydrous ethanol and milling beads in a ball mill and mill at 150~300 r / min for 8~16 h to obtain a mixed slurry. Step 3: Dry the mixed slurry at 60~110℃ for 24~48h to obtain powder; then grind the powder to a particle size of less than 75μm to obtain grinding material; Step 4: Mix the abrasive and the binder according to the mass ratio of abrasive to binder of 1:0.05~0.2, place them in a pre-pressing mold, pre-press under molding conditions of 10~20MPa, and then cold isostatically press under conditions of 100~200MPa to obtain the composite material preform. Step 5: Dry the composite preform at 60~110℃ for 24~48h, then cure it at 110~250℃ for 4~18h, and then place the cured composite preform in an atmosphere-protected furnace to remove the adhesive in an argon atmosphere to obtain the raw composite preform. Step 6: Place the raw composite material blank in a graphite crucible, and then place the graphite crucible in a high-temperature atmosphere sintering furnace; in an argon atmosphere: heat to 1600~1800℃ at a rate of 5~30℃ / min, hold for 60~180min, and cool with the furnace to obtain a high-strength corrosion-resistant Al4O4C-based composite material.

2. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The alumina powder has an Al4O4 content ≥ 99.9 wt% and a particle size of less than 20 μm.

3. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The yttrium oxide powder has a Y2O3 content ≥ 99.5 wt% and a particle size of less than 6 μm.

4. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The respective contents of the aluminum powder, alumina powder, and corundum powder are as follows: the Al content of the aluminum powder is ≥99wt%, the Al2O3 content of the alumina powder is ≥99wt%, and the Al2O3 content of the corundum powder is ≥98wt%.

5. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The binder is one of epoxy resin, phenolic resin and polyvinyl alcohol.

6. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The ball mill is either a horizontal ball mill or a planetary ball mill.

7. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The grinding beads are made of agate or zirconium oxide.

8. The method for preparing the high-strength, corrosion-resistant Al4O4C-based composite material as described in claim 1, characterized in that, The purity of the argon atmosphere is 99.99%; the flow rate is 15~20L / min.

9. A high-strength, corrosion-resistant Al4O4-based composite material, characterized in that... The high-strength corrosion-resistant Al4O4C-based composite material is a high-strength corrosion-resistant Al4O4-based composite material prepared by the preparation method of the high-strength corrosion-resistant Al4O4-based composite material according to any one of claims 1 to 8.