Preparation method of large-size aluminum-silicon crucible for high-temperature alloy smelting

Abstract

According to the preparation method of the large-size aluminum-silicon crucible for high-temperature alloy smelting, the dispersing agent is added, so that the dispersion stability of crucible slurry is improved, and segregation in the ceramic particle curing process is avoided; the method comprises the following steps: reasonably designing inner and outer mold materials of a crucible mold, connecting an electrophoresis power supply, taking a graphite inner mold as an anode, taking an aluminum outer mold as a cathode, injecting ceramic slurry into the mold, electrifying direct current, enabling ceramic particles in the slurry to be negatively charged, enabling aluminum oxide powder with relatively small particle size to move towards the anode to the surface of the inner wall of the crucible, and enabling coarse particles to be mainly positioned in the outer wall direction of the crucible; no complex surface treatment process is needed, operation is easy and convenient, and the erosion resistance and thermal shock resistance of the crucible can be improved at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic crucible preparation, and in particular relates to a method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting. Background Art

[0002] Large-sized aluminum-silicon crucibles are key components for vacuum melting of high-temperature alloys. High-temperature alloy melting places extremely high demands on large-sized aluminum-silicon crucibles. Large-sized aluminum-silicon crucibles need to withstand high temperatures when melting alloys, and cool rapidly after melting. They must withstand repeated heating and cooling processes during use, so large-sized aluminum-silicon crucibles are required to have excellent thermal shock stability; during vacuum melting, large-sized aluminum-silicon crucibles with alloy capacity ≥50Kg need to have excellent high-temperature alloy bearing capacity and microstructure uniformity; large-sized aluminum-silicon crucibles undergo interfacial reactions during long-term contact with alloy solutions, so large-sized aluminum-silicon crucibles need to have excellent corrosion resistance. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides the following technical solutions:

[0004] A method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting, comprising:

[0005] Step 1: First, pour deionized water into the material tank, add monomers and cross-linking agents, and disperse until completely dissolved to prepare a premixed solution;

[0006] Then, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, and sintering aid are sequentially added to the premixed liquid, and dispersed uniformly at high speed to obtain a ceramic slurry;

[0007] Among them, alumina A, alumina B, fused quartz A, and fused quartz B are four groups of raw materials with different D50 particle size ranges, and the D50 particle size ranges of alumina A, alumina B, fused quartz A, and fused quartz B are 0.1-1 μm, 1-10 μm, 10-100 μm, and 100-800 μm, respectively;

[0008] The mass proportions of deionized water, monomer, cross-linking agent, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, sintering aid, initiator and catalyst are 8-15wt%, 1-4wt%, 0.05-0.35wt%, 0.3-0.8wt%, 0.01-0.05wt%, 5-18wt%, 25-40wt%, 25-40wt%, 10-25wt%, 0.2-0.8wt%, 0.1-0.8wt% and 0.01-0.4wt% respectively;

[0009] Step 2: vacuum stirring the ceramic slurry to achieve a defoaming effect, thereby obtaining a defoamed ceramic slurry;

[0010] Step 3: Add initiator and catalyst to the defoamed ceramic slurry in sequence, and then pour it into the mold. The mold is electrically connected to the electrophoretic power supply, and the inner mold is connected to the anode and the outer mold is connected to the cathode. The electrophoretic power supply is turned on to perform electrophoretic deposition in a constant voltage mode. The slurry undergoes electrophoretic movement in the constant voltage mode and is then solidified to obtain a crucible blank. After drying at room temperature, it is dried and sintered to obtain a large-sized aluminum silicon crucible.

[0011] Furthermore, in step 1, the dispersion speed when preparing the premix is ​​400 to 1000 rpm.

[0012] Furthermore, in step 1, the monomer is acrylamide, the cross-linking agent is N,N-methylenebisacrylamide, and the dispersion speed for high-speed dispersion to uniformly obtain the ceramic slurry is 400-1000 rpm.

[0013] 4. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1 is characterized in that in step 1, the dispersant is a 20% concentration of isobam06 alkaline solution, isobam04 alkaline solution or isobam10 alkaline solution.

[0014] Furthermore, in step 1, the type of sintering aid is Sm2O3, La2O3, kaolin or Y2O3.

[0015] Furthermore, in step 2, the vacuum degree is -0.05 to -0.09 MPa, and the stirring speed is 30 to 60 rpm.

[0016] Furthermore, in step three, the initiator is ammonium persulfate and the catalyst is tetramethylethylenediamine.

[0017] Furthermore, in step three, the inner mold of the mold is made of graphite, the outer mold is made of aluminum, the working voltage of the electrophoretic deposition is 400-600V, the working time is 1-2 minutes, and the crucible curing molding time is 20-60 minutes.

[0018] Further, in step three, drying is performed at room temperature for 20 to 40 hours, and the drying procedure is as follows: heating at a rate of 5°C to 40°C, keeping warm for 4 to 8 hours, heating at a rate of 5°C to 80°C, keeping warm for 4 to 8 hours, heating at a rate of 5°C to 150°C, keeping warm for 4 to 8 hours.

[0019] Furthermore, in step three, the sintering system is to start from room temperature, increase the temperature to 300°C at a rate of 0.5-2°C, keep it warm for 1-8 hours, increase the temperature to 600°C at a rate of 1-3°C, keep it warm for 1-8 hours, increase the temperature to 1250-1500°C at a rate of 1-3°C, keep it warm for 1-8 hours, and then cool to room temperature with the furnace.

[0020] The present invention improves the dispersion stability of crucible slurry by adding a dispersant, and avoids segregation of ceramic particles during the solidification process; by reasonably designing the materials of the inner and outer molds of the crucible mold, the inner mold of the crucible mold is made of graphite, and the outer mold of the crucible mold is made of aluminum, an electrophoresis power supply is connected, the inner mold of the mold is connected to the anode, and the outer mold is connected to the cathode, and after the ceramic slurry is injected into the mold, power is turned on for electrophoretic deposition, the ceramic particles in the slurry are negatively charged, and alumina powder with a smaller particle size moves toward the anode and moves to the inner wall surface of the crucible, thereby improving the density of the inner wall of the crucible, without the need for a complex surface treatment process, and the operation is simple and convenient, thereby improving the corrosion resistance of the crucible, and avoiding the crucible from peeling off and falling into the alloy solution to cause leaf inclusions; fine particles are mainly located on the inner wall surface of the crucible, and coarse particles are mainly located in the direction of the outer wall of the crucible, and the corrosion resistance and thermal shock resistance of the crucible can be improved at the same time. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0022] Example 1

[0023] Step 1: First, pour deionized water into the material tank, add monomers and cross-linking agents, and disperse until completely dissolved to prepare a premixed solution;

[0024] Then, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, and sintering aid are sequentially added to the premixed liquid, and dispersed uniformly at high speed to obtain a ceramic slurry;

[0025] Step 2: vacuum stirring the ceramic slurry to achieve a defoaming effect, thereby obtaining a defoamed ceramic slurry;

[0026] Step 3: Add initiator and catalyst to the defoamed ceramic slurry in sequence, and then pour it into a mold. The mold is electrically connected to an electrophoretic power supply, wherein the inner mold of the mold is connected to the anode and the outer mold of the mold is connected to the cathode. The electrophoretic power supply is turned on, and electrophoretic deposition is performed in a constant voltage mode. The crucible blank is then solidified and formed. After drying at room temperature, it is dried and sintered to obtain a large-sized aluminum silicon crucible.

[0027] In this embodiment, the monomer is acrylamide, the cross-linking agent is N,N-methylenebisacrylamide, and the dispersion speed of the prepared premix and the prepared ceramic slurry is 800 rpm;

[0028] The dispersant is a 20% concentration of isobam06 alkaline solution;

[0029] The D50 particle size ranges of alumina A, alumina B, fused quartz A, and fused quartz B are 0.1-1 μm, 1-10 μm, 10-100 μm, and 100-800 μm, respectively;

[0030] The mass proportions of deionized water, monomer, cross-linking agent, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, sintering aid, initiator, and catalyst are 13wt%, 2wt%, 0.3wt%, 0.7wt%, 0.04wt%, 10.76wt%, 30wt%, 30wt%, 12wt%, 0.4wt%, 0.6wt%, and 0.2wt%, respectively;

[0031] The type of sintering aid is Y2O3;

[0032] In step 2, the vacuum degree was -0.07 MPa and the stirring speed was 30 rpm;

[0033] In step 3, the initiator is ammonium persulfate and the catalyst is tetramethylethylenediamine;

[0034] The inner mold of the mold is made of graphite, and the outer mold of the mold is made of aluminum; the working voltage of electrophoretic deposition is 550V, and the working time is 1 minute;

[0035] The curing time is 40 minutes;

[0036] Dry at room temperature for 30 hours. The drying procedure is as follows: increase the temperature to 40°C at a rate of 5°C, keep warm for 4 hours, increase the temperature to 80°C at a rate of 5°C, keep warm for 5 hours, increase the temperature to 150°C at a rate of 5°C, keep warm for 6 hours;

[0037] The sintering system is as follows: starting from room temperature, heating up to 300°C at a rate of 1°C, keeping warm for 3 hours, heating up to 600°C at a rate of 1°C, keeping warm for 4 hours, heating up to 1300°C at a rate of 1°C, keeping warm for 3 hours, and then cooling to room temperature with the furnace.

[0038] Example 2

[0039] The difference between this embodiment and embodiment 1 is:

[0040] In step 1, the dispersion speed when preparing the premix is ​​900 rpm;

[0041] The monomer is acrylamide, the cross-linking agent is N,N-methylenebisacrylamide, and the dispersion speed when preparing the ceramic slurry is 1000 rpm;

[0042] The dispersant is a 20% concentration of isobam04 alkaline solution;

[0043] The mass proportions of deionized water, monomer, cross-linking agent, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, sintering aid, initiator, and catalyst are 12wt%, 2.5wt%, 0.2wt%, 0.5wt%, 0.03wt%, 14.4wt%, 28wt%, 27wt%, 14.57wt%, 0.4wt%, 0.3wt%, and 0.1wt%, respectively;

[0044] The type of sintering aid is La2O3.

[0045] In step 2, the vacuum degree was -0.08 MPa and the stirring speed was 40 rpm;

[0046] In step 3, the working voltage of electrophoretic deposition is 450V, the working time is 2 minutes, and the crucible curing time is 50 minutes;

[0047] Dry at room temperature for 40 hours. The drying procedure is as follows: heat up to 40°C at a rate of 5°C, keep warm for 8 hours, heat up to 80°C at a rate of 5°C, keep warm for 6 hours, heat up to 150°C at a rate of 5°C, keep warm for 5 hours.

[0048] The sintering system is as follows: starting from room temperature, heating up to 300°C at a rate of 0.5°C, keeping warm for 6 hours, heating up to 600°C at a rate of 2°C, keeping warm for 2 hours, heating up to 1300°C at a rate of 2°C, keeping warm for 4 hours, and then cooling to room temperature with the furnace.

[0049] Example 3

[0050] The difference between this embodiment and embodiment 1 is:

[0051] In step one,

[0052] The mass proportions of deionized water, monomer, cross-linking agent, dispersant, ammonia water, alumina A, alumina B, fused quartz A, fused quartz B, sintering aid, initiator and catalyst are 11wt%, 1.8wt%, 0.2wt%, 0.6wt%, 0.03wt%, 12.55wt%, 30wt%, 29.32wt%, 13wt%, 0.4wt%, 0.8wt% and 0.3wt% respectively.

[0053] The type of sintering aid is Sm2O3.

[0054] In step 2, the stirring speed is 45 rpm;

[0055] In step three,

[0056] The working voltage of electrophoretic deposition is 500 V, the working time is 1.5 minutes, and the crucible solidification time is 30 minutes.

[0057] Dry at room temperature for 24 hours. The drying procedure is as follows: increase the temperature to 40°C at a rate of 5°C, keep warm for 8 hours, increase the temperature to 80°C at a rate of 5°C, keep warm for 8 hours, increase the temperature to 150°C at a rate of 5°C, keep warm for 8 hours.

[0058] The sintering system is as follows: starting from room temperature, heating up to 300°C at a rate of 0.5°C, keeping warm for 4 hours, heating up to 600°C at a rate of 0.5°C, keeping warm for 6 hours, heating up to 1360°C at a rate of 0.5°C, keeping warm for 2 hours, and then cooling to room temperature with the furnace.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting, characterized in that: include: Step 1: First, pour deionized water into the material tank, add monomers and cross-linking agents, and disperse until completely dissolved to prepare a premixed solution; Then, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, and sintering aid are sequentially added to the premixed liquid, and dispersed uniformly at high speed to obtain a ceramic slurry; Among them, alumina A, alumina B, fused quartz A, and fused quartz B are four groups of raw materials with different D50 particle size ranges, and the D50 particle size ranges of alumina A, alumina B, fused quartz A, and fused quartz B are 0.1-1 μm, 1-10 μm, 10-100 μm, and 100-800 μm, respectively; The mass proportions of deionized water, monomer, cross-linking agent, dispersant, ammonia water, aluminum oxide A, aluminum oxide B, fused quartz A, fused quartz B, sintering aid, initiator and catalyst are 8-15wt%, 1-4wt%, 0.05-0.35wt%, 0.3-0.8wt%, 0.01-0.05wt%, 5-18wt%, 25-40wt%, 25-40wt%, 10-25wt%, 0.2-0.8wt%, 0.1-0.8wt% and 0.01-0.4wt% respectively; Step 2: vacuum stirring the ceramic slurry to achieve a defoaming effect, thereby obtaining a defoamed ceramic slurry; Step 3: Add initiator and catalyst to the defoamed ceramic slurry in sequence, and then pour it into the mold. The mold is electrically connected to the electrophoretic power supply, and the inner mold is connected to the anode and the outer mold is connected to the cathode. The electrophoretic power supply is turned on to perform electrophoretic deposition in a constant voltage mode, and then solidify and shape to obtain a crucible blank. After drying at room temperature, it is dried and sintered to obtain a large-sized aluminum silicon crucible.

2. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step 1, the dispersion speed when preparing the premix is ​​400 to 1000 rpm.

3. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step 1, the monomer is acrylamide, the cross-linking agent is N,N-methylenebisacrylamide, and the dispersion speed for high-speed dispersion to uniformly obtain the ceramic slurry is 400-1000 rpm.

4. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step 1, the dispersant is a 20% concentration of isobam06 alkaline solution, isobam04 alkaline solution or isobam10 alkaline solution.

5. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step 1, the sintering aid is Sm2O3, La2O3, kaolin or Y2O3.

6. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step 2, the vacuum degree is -0.05 to -0.09 MPa, and the stirring speed is 30 to 60 rpm.

7. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step 3, the initiator is ammonium persulfate and the catalyst is tetramethylethylenediamine.

8. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step three, the inner mold of the mold is made of graphite, the outer mold is made of aluminum, the working voltage of electrophoretic deposition is 400-600V, the working time is 1-2 minutes, and the crucible curing molding time is 20-60 minutes.

9. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step three, dry at room temperature for 20 to 40 hours, and the drying procedure is as follows: heat up to 40°C at a rate of 5°C, keep warm for 4 to 8 hours, heat up to 80°C at a rate of 5°C, keep warm for 4 to 8 hours, heat up to 150°C at a rate of 5°C, keep warm for 4 to 8 hours.

10. The method for preparing a large-sized aluminum-silicon crucible for high-temperature alloy smelting according to claim 1, characterized in that: In step three, the sintering system is to start from room temperature, heat up to 300°C at a rate of 0.5-2°C, keep warm for 1-8 hours, heat up to 600°C at a rate of 1-3°C, keep warm for 1-8 hours, heat up to 1250-1500°C at a rate of 1-3°C, keep warm for 1-8 hours, and then cool to room temperature with the furnace.