Graphene-whisker composite water-soluble wax material for precision investment casting and preparation method thereof

Abstract

The application discloses a graphene-whisker composite water-soluble wax material for precision investment casting and a preparation method thereof. The water-soluble wax material comprises a base material, a surfactant, a water-soluble component, a fiber component, a whisker component and graphene, and the content of each component is 30-47 wt% of the base material, 3.5-9 wt% of the surfactant, 12-26 wt% of the water-soluble component, 3-8 wt% of the fiber component, 8-22 wt% of the whisker component and 0.5-5 wt% of the graphene. The preparation method comprises the following steps: putting different molecular weight polyethylene glycol, polyvinyl alcohol and urea in the base material into a blender, and stirring until melting at a certain temperature; adding each component in the surfactant and continuing to stir; mixing each component in the water-soluble component, and then adding and continuing to stir; mixing each component in the fiber component and the whisker component, and then adding and continuing to stir; adding the graphene and continuing to stir, so as to obtain the graphene-whisker composite water-soluble wax material. The water-soluble wax material has excellent toughness, strength and heat resistance, and meanwhile, the water-soluble wax material maintains excellent water solubility and has no residual alkali metal ion after water dissolving.

Description

Technical Field

[0001] This invention belongs to the technical field of special functional materials for investment casting, specifically relating to a graphene-whisker composite water-soluble wax material and its preparation method for investment casting. It is particularly suitable for high-temperature alloy investment casting processes. This water-soluble wax material is a key material for forming complex multi-layered ceramic cores, hollow ceramic cores, and complex hollow wax models. Background Technology

[0002] In investment casting, water-soluble wax materials are widely used due to their excellent water solubility, which allows for efficient dewaxing without the need for organic solvents. This makes the process simple and environmentally friendly. However, in high-temperature alloy investment casting, the molding of complex multi-walled ceramic cores, hollow ceramic cores, and complex hollow wax patterns places higher demands on water-soluble wax materials.

[0003] Currently, existing water-soluble wax materials generally suffer from insufficient mechanical properties, primarily manifested as insufficient toughness and low strength. During the casting process, they are prone to cracking under external forces, thus affecting the dimensional accuracy and metallurgical quality of the castings. Furthermore, some water-soluble wax materials have poor heat resistance, easily softening and deforming at high temperatures, further impacting the dimensional accuracy and metallurgical quality of the castings. This limits the application of water-soluble wax materials in the production of some high-precision, high-requirement castings. More importantly, existing water-soluble wax materials often leave residual alkali metal ions after dissolution. These residual alkali metal ions can cause interfacial reactions between the ceramic core / shell and the high-temperature alloy liquid, leading to interface contamination of the high-temperature alloy liquid and severely affecting the metallurgical quality of the high-temperature alloy castings.

[0004] Given the aforementioned technical bottlenecks, there is an urgent need to develop a water-soluble wax material with high toughness, high strength, good heat resistance, and water solubility, and which leaves no alkali metal ion residue after water dissolution, in order to break through the performance boundaries of existing water-soluble wax materials and provide key process support for the manufacturing of high-temperature alloy investment castings. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a graphene-whisker composite water-soluble wax material for investment casting. The water-soluble wax material contains the following components by mass percentage: matrix material 30-47 wt%, surfactant 3.5-9 wt%, water-soluble component 12-26 wt%, fiber component 3-8 wt%, whisker component 8-22 wt%, and graphene 0.5-5 wt%, with the total content of each component being 100 wt%.

[0006] Preferably, the mass percentage of each substance in the matrix material is 44-65 wt% polyethylene glycol, 25-46 wt% polyvinyl alcohol, and 10-23 wt% urea.

[0007] In any of the above embodiments, it is preferred that the polyethylene glycol is a compound system designed with a molecular weight gradient, wherein the polyethylene glycol in the low molecular weight range of 1000-2000, the medium molecular weight range of 6000-8000, and the high molecular weight range of 10000-14000 accounts for 40-50 wt%, 30-40 wt%, and 20-30 wt% of the total polyethylene glycol, respectively.

[0008] In any of the above embodiments, it is preferred that, in the low molecular weight polyethylene glycol (1000-2000), the mass ratio of polyethylene glycol with a molecular weight of 1000 to that with a molecular weight of 2000 is 2:1; in the medium molecular weight polyethylene glycol (6000-8000), the mass ratio of polyethylene glycol with a molecular weight of 6000 to that with a molecular weight of 8000 is 2:1; and in the high molecular weight polyethylene glycol (10000-14000), the mass ratio of polyethylene glycol with a molecular weight of 10000, a molecular weight of 12000, and a molecular weight of 14000 is 3:2:1.

[0009] In any of the above embodiments, it is preferred that the mass percentage of each substance in the surfactant is 22-32 wt% stearic acid, 22-32 wt% fatty acid, 15-25 wt% sodium stearate, 10-18 wt% sodium dodecyl sulfate, and 10-18 wt% sodium dodecylbenzene sulfonate.

[0010] In any of the above embodiments, it is preferred that the mass percentage of each substance in the water-soluble component is 26-38 wt% sodium chloride, 18-30 wt% sodium bicarbonate, 16-26 wt% ammonium chloride, 8-18 wt% talc, and 8-16 wt% mica powder; the median particle size of the talc and the mica powder is 1-10 μm.

[0011] In any of the above embodiments, it is preferred that the mass percentage of each substance in the fiber component is 18-32 wt% nylon fiber, 28-44 wt% carbon fiber, and 28-44 wt% carboxymethyl cellulose; the diameter of the nylon fiber and the carbon fiber are both controlled within the range of 5-15 μm, and the aspect ratio is both controlled within the range of 15-25:1.

[0012] In any of the above embodiments, preferably, the mass percentage of each substance in the whisker component is as follows: mullite whiskers 18-30 wt%, alumina whiskers 15-26 wt%, silicon oxide whiskers 8-18 wt%, silicon carbide whiskers 8-18 wt%, and organic whiskers 15-26 wt%; and the mass percentage of each substance in the organic whisker is as follows: polyamide whiskers 30-40 wt% and chitosan whiskers 60-70 wt%.

[0013] In any of the above embodiments, it is preferred that the diameters of the mullite whiskers, the alumina whiskers, the silicon oxide whiskers, and the silicon carbide whiskers are all controlled within the range of 1-5 μm and the aspect ratios are all controlled within the range of 15-25:1; the diameters of the polyamide whiskers and the chitin whiskers are all controlled within the range of 0.5-1 μm and the aspect ratios are all controlled within the range of 5-15:1.

[0014] This invention also provides a method for preparing a graphene-whisker composite water-soluble wax material for investment casting, the preparation method comprising the following steps in sequence:

[0015] Step 1: Weigh out each raw material according to the designed material ratio and set aside;

[0016] Step 2: Put all the water-soluble components, including sodium chloride, sodium bicarbonate, ammonium chloride, talc powder, and mica powder, into a V-type mixer and mix them at room temperature for a certain period of time to ensure that the components are mixed evenly, thus obtaining a composite powder material. Take it out for later use.

[0017] Step 3: Put all the materials in the fiber component (nylon fiber, carbon fiber, carboxymethyl cellulose) and the materials in the whisker component (mullite whiskers, alumina whiskers, silicon dioxide whiskers, silicon carbide whiskers, polyamide whiskers, chitosan whiskers) into a V-type mixer and mix them at room temperature for a certain period of time to make the materials evenly mixed, so as to obtain a fiber-whisker multi-size reinforcing material, which can be taken out for later use.

[0018] Step 4: Place polyethylene glycols with molecular weights of 10,000, 12,000, and 14,000 from the matrix material into a mixer, and heat while stirring. After heating to a certain temperature, continue stirring for a certain period of time. Keeping the temperature inside the mixer constant, add polyethylene glycols with molecular weights of 1,000, 2,000, 6,000, and 8,000 to the mixer and continue stirring for a certain period of time. Add polyvinyl alcohol and urea from the matrix material into the mixer, and heat while stirring. After heating to a certain temperature, continue stirring for a certain period of time to completely melt all the substances in the matrix material, thus obtaining the initial matrix slurry.

[0019] Step 5: Keep the temperature inside the mixer constant, add all the surfactants stearic acid, fatty acid, sodium stearate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate into the mixer, and continue stirring for a certain period of time to ensure that the substances are evenly dispersed, thus obtaining the modified matrix slurry.

[0020] Step Six: Keep the temperature inside the mixer constant, add the composite powder material into the mixer, and continue mixing for a certain period of time to ensure that all substances are completely combined;

[0021] Step 7: Keep the temperature inside the mixer constant, add the fiber-whisker multi-size reinforcing material into the mixer, and continue mixing for a certain period of time to ensure that the fiber-whisker multi-size reinforcing material is evenly dispersed;

[0022] Step 8: Keep the temperature inside the mixer constant, add graphene to the mixer, and continue stirring for a certain period of time to ensure that all substances are mixed evenly, thus obtaining the graphene-whisker composite water-soluble wax material.

[0023] Step 9: The graphene-whisker composite water-soluble wax material is molded, cooled and demolded to obtain an ingot, which is then sealed and stored for subsequent high-temperature alloy investment casting process.

[0024] Preferably, in step two, the mixing rate of each substance in the water-soluble component is 50-100 r / min and the mixing time is 10-15 min.

[0025] In any of the above schemes, it is preferred that, in step three, the mixing rate of each substance in the fiber component and each substance in the whisker component is 100-150 r / min and the mixing time is 20-30 min.

[0026] In any of the above schemes, preferably, in step four, polyethylene glycol with molecular weights of 10,000, 12,000, and 14,000 is placed in a mixer, and the mixing speed is 100-200 r / min. After heating the temperature to 70-90℃, the mixing continues for 20-50 min. While maintaining the temperature inside the mixer at 70-90℃, polyethylene glycol with molecular weights of 1,000, 2,000, 6,000, and 8,000 is added to the mixer and the mixing continues for 20-50 min. Polyvinyl alcohol and urea are added to the mixer, and the mixing speed is 100-200 r / min. After raising the temperature to 100-120℃, the mixing continues for 30-80 min.

[0027] In any of the above schemes, it is preferred that, in step five, the temperature inside the mixer is maintained at 100-120℃, and the various substances in the surfactant are added to the mixer and stirred for 2-3 hours.

[0028] In any of the above schemes, it is preferred that, in step six, the temperature inside the mixer is maintained at 100-120℃, and the composite powder material is added to the mixer and stirred for 2-3 hours.

[0029] In any of the above schemes, it is preferred that, in step seven, the temperature inside the mixer is maintained at 100-120°C, and the fiber-whisker multi-size reinforcing material is added to the mixer and stirred for 5-8 hours.

[0030] In any of the above schemes, it is preferred that, in step eight, the temperature inside the mixer is maintained at 100-120℃, and the graphene is added to the mixer and stirred for 3-4 hours.

[0031] In this invention, the V-type mixer, agitator (heated type), and injection molding machine used are all traditional equipment, with no special requirements on equipment structure or model. Throughout the preparation process of the graphene-whisker composite water-soluble wax material, the selection and proportioning of each component, the proportioning of polyethylene glycols with different molecular weights, the selection and proportioning of various whiskers, the limitation of fiber and whisker sizes, the order of addition of each component, and process parameters are all crucial. These parameters need to work synergistically to achieve the technical effects expected by this invention.

[0032] The graphene-whisker composite water-soluble wax material and its preparation method for investment casting of the present invention have the following beneficial effects:

[0033] (1) The water-soluble wax material of the present invention has excellent toughness, strength and heat resistance, while maintaining excellent water solubility. After water dissolution, there is no alkali metal ion residue, which can effectively solve the problem of interface reaction between ceramic core / ceramic shell and alloy liquid caused by alkali metal ion residue after water-soluble wax dissolution. It meets the high performance requirements of wax material for forming complex structure multi-walled ceramic cores, hollow structure ceramic cores and complex structure hollow wax molds in high temperature alloy investment casting process.

[0034] (2) This invention uses graphene combined with various whiskers (mullite whiskers, alumina whiskers, silicon oxide whiskers, silicon carbide whiskers, and organic whiskers) as a toughening and reinforcing phase. Graphene has excellent mechanical and thermal properties, which can significantly improve the toughness and strength of wax materials; the synergistic effect of various whiskers and graphene can further enhance the mechanical properties and heat resistance of wax materials, making it less prone to cracking and deformation during investment casting.

[0035] (3) The water-soluble wax material of the present invention contains water-soluble components and surfactants, which gives the water-soluble wax material excellent water solubility. After dissolving in water, there is no alkali metal ion residue, which can effectively solve the problem of interfacial reaction between ceramic core / ceramic shell and alloy liquid caused by alkali metal ion residue after water-soluble wax dissolution. The dewaxing process is simple and efficient, which can shorten the production cycle. At the same time, carboxymethyl cellulose is also added to further improve the water solubility and dispersibility of the water-soluble wax material.

[0036] (4) Nylon fiber and carbon fiber are added to the water-soluble wax material of the present invention, which further enhances the toughness and strength of the water-soluble wax material. The fiber works synergistically with other components to significantly improve the comprehensive performance of the water-soluble wax material and meet the stringent requirements of high-temperature alloy investment casting process.

[0037] (5) The present invention combines urea with polyethylene glycol and polyvinyl alcohol designed with molecular weight gradients to better improve the molding performance, stability and compatibility of water-soluble wax materials.

[0038] (6) The preparation method of the present invention can stably prepare water-soluble wax material with excellent performance for investment casting by precisely controlling the rotation speed and mixing time of the V-type mixer, the rotation speed and stirring time of the agitator, and the stirring temperature. It can ensure that the components are evenly dispersed, and the process is simple and convenient to operate, which is conducive to industrial production. Attached Figure Description

[0039] Figure 1 A photograph of the initial matrix slurry prepared according to a preferred embodiment of the graphene-whisker composite water-soluble wax material and preparation method for investment casting of the present invention;

[0040] Figure 2 for Figure 1 Photograph of the graphene-whisker composite water-soluble wax material prepared in the illustrated embodiment;

[0041] Figure 3 for Figure 1 A photograph of the ingot obtained by injection molding of graphene-whisker composite water-soluble wax material in the illustrated embodiment.

[0042] Figure 4 To adopt Figure 1 Microscopic photograph of hollow ceramic core prepared by water-soluble wax material in the embodiment shown after water dissolution;

[0043] Figure 5 To adopt Figure 1 The energy spectrum of the hollow ceramic core prepared by water-soluble wax material in the embodiment shown. Detailed Implementation

[0044] To further understand the invention, the following detailed description of the invention will be provided in conjunction with specific embodiments.

[0045] Example 1:

[0046] According to a preferred embodiment of the graphene-whisker composite water-soluble wax material for investment casting of the present invention, the mass percentage of each substance in the water-soluble wax material is as follows: matrix material 43wt%, surfactant 7wt%, water-soluble component 20wt%, fiber component 6wt%, whisker component 20wt%, and graphene 4wt%.

[0047] The matrix material comprises polyethylene glycol (PEG) at a mass percentage of 52 wt%, polyvinyl alcohol (PVA) at 33 wt%, and urea at 15 wt%. The PEG is a molecular weight gradient compound system, wherein the PEGs with low molecular weights (1000-2000), medium molecular weights (6000-8000), and high molecular weights (10000-14000) account for 45 wt%, 35 wt%, and 20 wt% of the total PEG mass, respectively.

[0048] In the low molecular weight polyethylene glycol (1000-2000), the mass ratio of polyethylene glycol with a molecular weight of 1000 to that with a molecular weight of 2000 is 2:1; in the medium molecular weight polyethylene glycol (6000-8000), the mass ratio of polyethylene glycol with a molecular weight of 6000 to that with a molecular weight of 8000 is 2:1; and in the high molecular weight polyethylene glycol (10000-14000), the mass ratio of polyethylene glycol with a molecular weight of 10000, 12000, and 14000 is 3:2:1.

[0049] The mass percentages of each substance in the surfactant are as follows: stearic acid 26wt%, fatty acid 26wt%, sodium stearate 20wt%, sodium dodecyl sulfate 14wt%, and sodium dodecylbenzene sulfonate 14wt%.

[0050] The water-soluble components comprise the following mass percentages: sodium chloride 32 wt%, sodium bicarbonate 24 wt%, ammonium chloride 21 wt%, talc 12 wt%, and mica powder 11 wt%; the median particle size of both the talc and the mica powder is 5 μm.

[0051] The mass percentage of each substance in the fiber component is 26wt% nylon fiber, 37wt% carbon fiber, and 37wt% carboxymethyl cellulose; the diameter of the nylon fiber and the carbon fiber are both controlled within the range of 5-15μm, and the aspect ratio is controlled within the range of 15-25:1.

[0052] The mass percentages of each substance in the whisker component are as follows: 26 wt% mullite whiskers, 22 wt% alumina whiskers, 15 wt% silicon oxide whiskers, 15 wt% silicon carbide whiskers, and 22 wt% organic whiskers; the mass percentages of each substance in the organic whiskers are as follows: 35 wt% polyamide whiskers and 65 wt% chitosan whiskers.

[0053] The diameters of the mullite whiskers, alumina whiskers, silicon oxide whiskers, and silicon carbide whiskers are all controlled within the range of 1-5 μm, and the aspect ratios are all controlled within the range of 15-25:1; the diameters of the polyamide whiskers and chitin whiskers are all controlled within the range of 0.5-1 μm, and the aspect ratios are all controlled within the range of 5-15:1.

[0054] This embodiment also provides a method for preparing a graphene-whisker composite water-soluble wax material for investment casting, the preparation method comprising the following steps in sequence:

[0055] Step 1: Weigh out each raw material according to the designed material ratio and set aside;

[0056] Step 2: Put all the water-soluble components, including sodium chloride, sodium bicarbonate, ammonium chloride, talc powder, and mica powder, into a V-type mixer and mix them at room temperature for a certain period of time to ensure that the components are mixed evenly, thus obtaining a composite powder material. Take it out for later use.

[0057] Step 3: Put all the materials in the fiber component (nylon fiber, carbon fiber, carboxymethyl cellulose) and the materials in the whisker component (mullite whiskers, alumina whiskers, silicon dioxide whiskers, silicon carbide whiskers, polyamide whiskers, chitosan whiskers) into a V-type mixer and mix them at room temperature for a certain period of time to make the materials evenly mixed, so as to obtain a fiber-whisker multi-size reinforcing material, which can be taken out for later use.

[0058] Step 4: Place polyethylene glycols with molecular weights of 10,000, 12,000, and 14,000 from the matrix material into a mixer, and heat while stirring. After heating to a certain temperature, continue stirring for a certain period of time. Keeping the temperature inside the mixer constant, add polyethylene glycols with molecular weights of 1,000, 2,000, 6,000, and 8,000 to the mixer and continue stirring for a certain period of time. Add polyvinyl alcohol and urea from the matrix material into the mixer, and heat while stirring. After heating to a certain temperature, continue stirring for a certain period of time to completely melt all the substances in the matrix material, thus obtaining the initial matrix slurry.

[0059] Step 5: Keep the temperature inside the mixer constant, add all the surfactants stearic acid, fatty acid, sodium stearate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate into the mixer, and continue stirring for a certain period of time to ensure that the substances are evenly dispersed, thus obtaining the modified matrix slurry.

[0060] Step Six: Keep the temperature inside the mixer constant, add the composite powder material into the mixer, and continue mixing for a certain period of time to ensure that all substances are completely combined;

[0061] Step 7: Keep the temperature inside the mixer constant, add the fiber-whisker multi-size reinforcing material into the mixer, and continue mixing for a certain period of time to ensure that the fiber-whisker multi-size reinforcing material is evenly dispersed;

[0062] Step 8: Keep the temperature inside the mixer constant, add graphene to the mixer, and continue stirring for a certain period of time to ensure that all substances are mixed evenly, thus obtaining the graphene-whisker composite water-soluble wax material.

[0063] Step 9: The graphene-whisker composite water-soluble wax material is molded, cooled and demolded to obtain an ingot, which is then sealed and stored for subsequent high-temperature alloy investment casting process.

[0064] In step two, the mixing rate of each substance in the water-soluble component is 75 r / min and the mixing time is 12 min.

[0065] In step three, the mixing rate of each substance in the fiber component and each substance in the whisker component is 125 r / min, and the mixing time is 25 min.

[0066] In step four, polyethylene glycol with molecular weights of 10,000, 12,000, and 14,000 is placed in a mixer at a stirring speed of 150 rpm. After heating to 80°C, stirring continues for 35 minutes. While maintaining the temperature inside the mixer at 80°C, polyethylene glycol with molecular weights of 1,000, 2,000, 6,000, and 8,000 is added to the mixer and stirring continues for 35 minutes. Polyvinyl alcohol and urea are then added to the mixer at a stirring speed of 150 rpm. After raising the temperature to 110°C, stirring continues for 55 minutes.

[0067] In step five, maintain the temperature inside the mixer at 110°C, add all the surfactants into the mixer and continue mixing for 2.5 hours.

[0068] In step six, maintain the temperature inside the mixer at 110°C, add the composite powder material into the mixer and continue mixing for 2.5 hours.

[0069] In step seven, the temperature inside the mixer is kept at 110°C, and the fiber-whisker multi-size reinforcing material is added to the mixer and stirred for 6.5 hours.

[0070] In step eight, maintain the temperature inside the mixer at 110°C, add graphene to the mixer and continue mixing for 3.5 hours.

[0071] In this embodiment, the prepared initial matrix slurry is as follows: Figure 1 As shown, the prepared graphene-whisker composite water-soluble wax material is as follows: Figure 2 As shown, the ingot obtained by injection molding of graphene-whisker composite water-soluble wax material is as follows: Figure 3 As shown.

[0072] Hollow ceramic cores were further prepared using the water-soluble wax material prepared in this embodiment. The microstructure after water dissolution is as follows: Figure 4 As shown, the energy spectrum analysis is as follows: Figure 5 As shown in the figure, there are no alkali metal ions or alkaline earth metal ions remaining after water dissolution, therefore no interfacial reaction occurs between the ceramic core / ceramic shell and the alloy liquid.

[0073] The graphene-whisker composite water-soluble wax material and preparation method for investment casting in this embodiment have the following beneficial effects: (1) It has excellent toughness, strength and heat resistance, while maintaining excellent water solubility. After water dissolution, there is no alkali metal ion residue, which can effectively solve the problem of interface reaction between ceramic core / ceramic shell and alloy liquid caused by alkali metal ion residue after water-soluble wax dissolution. It meets the high performance requirements of wax material for forming complex multi-layer wall ceramic cores, hollow ceramic cores and complex hollow wax molds in high-temperature alloy investment casting process. (2) Graphene and various whiskers are used as toughening and reinforcing phases, which significantly improves the toughness and strength of wax material, making it less prone to cracking and deformation during investment casting. (3) Water-soluble components and surfactants are added, and there is no alkali metal ion residue after water dissolution. This can effectively solve the problem of interface reaction between ceramic core / ceramic shell and alloy liquid caused by alkali metal ion residue after water dissolution. (4) The addition of nylon and carbon fibers further enhances the toughness and strength of the water-soluble wax material. The fibers work synergistically with other components to significantly improve the overall performance of the wax. (5) The synergistic effect of urea with polyethylene glycol and polyvinyl alcohol with molecular weight gradient design better improves the molding performance, stability and compatibility of the wax. (6) By precisely controlling the speed and mixing time of the V-type mixer, the speed and stirring time of the agitator, the stirring temperature and other parameters, high-performance water-soluble wax materials for investment casting can be stably prepared, which is beneficial to industrial production.

[0074] Example 2:

[0075] According to another preferred embodiment of the graphene-whisker composite water-soluble wax material and preparation method for investment casting of the present invention, the material selection and proportion of each component, process flow and process parameters, technical principle, and beneficial effects are basically the same as those in Embodiment 1, except that:

[0076] The mass percentages of each substance in the water-soluble wax material are as follows: matrix material 42wt%, surfactant 9wt%, water-soluble component 18wt%, fiber component 8wt%, whisker component 18wt%, and graphene 5wt%.

[0077] The matrix material comprises polyethylene glycol (PEG) 44 wt%, polyvinyl alcohol (PVA) 46 wt%, and urea 10 wt% by mass. The PEG is a molecular weight gradient compound system, wherein the PEGs with low molecular weights (1000-2000), medium molecular weights (6000-8000), and high molecular weights (10000-14000) account for 40 wt%, 30 wt%, and 30 wt% of the total PEG by mass, respectively.

[0078] In the low molecular weight polyethylene glycol (1000-2000), the mass ratio of polyethylene glycol with a molecular weight of 1000 to that with a molecular weight of 2000 is 2:1; in the medium molecular weight polyethylene glycol (6000-8000), the mass ratio of polyethylene glycol with a molecular weight of 6000 to that with a molecular weight of 8000 is 2:1; and in the high molecular weight polyethylene glycol (10000-14000), the mass ratio of polyethylene glycol with a molecular weight of 10000, 12000, and 14000 is 3:2:1.

[0079] The surfactant comprises the following components by mass percentage: stearic acid 22wt%, fatty acid 32wt%, sodium stearate 15wt%, sodium dodecyl sulfate 18wt%, and sodium dodecylbenzene sulfonate 13wt%.

[0080] The water-soluble components comprise the following mass percentages: sodium chloride 26 wt%, sodium bicarbonate 30 wt%, ammonium chloride 16 wt%, talc 18 wt%, and mica powder 10 wt%; the median particle size of both the talc and the mica powder is 1 μm.

[0081] The mass percentage of each substance in the fiber component is 20wt% nylon fiber, 40wt% carbon fiber, and 40wt% carboxymethyl cellulose; the diameter of the nylon fiber and the carbon fiber are both controlled within the range of 5-15μm, and the aspect ratio is controlled within the range of 15-25:1.

[0082] The mass percentages of each substance in the whisker component are as follows: mullite whiskers 18 wt%, alumina whiskers 26 wt%, silicon oxide whiskers 18 wt%, silicon carbide whiskers 18 wt%, and organic whiskers 20 wt%. The mass percentages of each substance in the organic whiskers are as follows: polyamide whiskers 30 wt% and chitosan whiskers 70 wt%. The diameters of the mullite whiskers, alumina whiskers, silicon oxide whiskers, and silicon carbide whiskers are all controlled within the range of 1-5 μm, and their aspect ratios are all controlled within the range of 15-25:1. The diameters of the polyamide whiskers and chitosan whiskers are all controlled within the range of 0.5-1 μm, and their aspect ratios are all controlled within the range of 5-15:1.

[0083] In step two, the mixing rate of each substance in the water-soluble component is 50 r / min and the mixing time is 15 min.

[0084] In step three, the mixing rate of each substance in the fiber component and each substance in the whisker component is 100 r / min, and the mixing time is 30 min.

[0085] In step four, polyethylene glycol with molecular weights of 10,000, 12,000, and 14,000 is placed in a mixer at a stirring speed of 100 rpm. The temperature is heated to 70°C and stirring is continued for 50 minutes. While maintaining the temperature inside the mixer at 70°C, polyethylene glycol with molecular weights of 1,000, 2,000, 6,000, and 8,000 is added to the mixer and stirring is continued for 50 minutes. Polyvinyl alcohol and urea are added to the mixer at a stirring speed of 100 rpm. The temperature is raised to 100°C and stirring is continued for 80 minutes.

[0086] In step five, keep the temperature inside the mixer at 100°C, add all the surfactants into the mixer and continue mixing for 3 hours.

[0087] In step six, maintain the temperature inside the mixer at 100°C, add the composite powder material into the mixer and continue mixing for 3 hours.

[0088] In step seven, the temperature inside the mixer is kept at 100°C, and the fiber-whisker multi-size reinforcing material is added to the mixer and stirred for another 8 hours.

[0089] In step eight, keep the temperature inside the mixer at 100°C, add the graphene to the mixer and continue stirring for 4 hours.

[0090] Example 3:

[0091] According to another preferred embodiment of the graphene-whisker composite water-soluble wax material and preparation method for investment casting of the present invention, the material selection and proportion of each component, process flow and process parameters, technical principle, and beneficial effects are basically the same as those in Embodiment 1, except that:

[0092] The mass percentages of each substance in the water-soluble wax material are as follows: matrix material 45wt%, surfactant 4wt%, water-soluble component 24wt%, fiber component 3wt%, whisker component 21wt%, and graphene 3wt%.

[0093] The matrix material comprises polyethylene glycol (PEG) 55 wt%, polyvinyl alcohol (PVA) 25 wt%, and urea 20 wt% by mass. The PEG is a molecular weight gradient compound system, wherein the PEGs with low molecular weights (1000-2000), medium molecular weights (6000-8000), and high molecular weights (10000-14000) account for 42 wt%, 32 wt%, and 26 wt% of the total PEG by mass, respectively.

[0094] In the low molecular weight polyethylene glycol (1000-2000), the mass ratio of polyethylene glycol with a molecular weight of 1000 to that with a molecular weight of 2000 is 2:1; in the medium molecular weight polyethylene glycol (6000-8000), the mass ratio of polyethylene glycol with a molecular weight of 6000 to that with a molecular weight of 8000 is 2:1; and in the high molecular weight polyethylene glycol (10000-14000), the mass ratio of polyethylene glycol with a molecular weight of 10000, 12000, and 14000 is 3:2:1.

[0095] The surfactant comprises the following components by mass percentage: stearic acid 30wt%, fatty acid 22wt%, sodium stearate 22wt%, sodium dodecyl sulfate 10wt%, and sodium dodecylbenzene sulfonate 16wt%.

[0096] The water-soluble components comprise the following mass percentages: sodium chloride 35 wt%, sodium bicarbonate 18 wt%, ammonium chloride 26 wt%, talc 8 wt%, and mica powder 13 wt%; the median particle size of both the talc and the mica powder is 10 μm.

[0097] The mass percentage of each substance in the fiber component is 32wt% nylon fiber, 34wt% carbon fiber, and 34wt% carboxymethyl cellulose; the diameter of the nylon fiber and the carbon fiber are both controlled within the range of 5-15μm, and the aspect ratio is controlled within the range of 15-25:1.

[0098] The whisker composition comprises, by mass percentage, 30 wt% mullite whiskers, 20 wt% alumina whiskers, 12 wt% silicon oxide whiskers, 12 wt% silicon carbide whiskers, and 26 wt% organic whiskers; the organic whiskers comprise, by mass percentage, 40 wt% polyamide whiskers and 60 wt% chitosan whiskers. The diameters of the mullite, alumina, silicon oxide, and silicon carbide whiskers are all controlled within the range of 1-5 μm, and their aspect ratios are all controlled within the range of 15-25:1; the diameters of the polyamide and chitosan whiskers are all controlled within the range of 0.5-1 μm, and their aspect ratios are all controlled within the range of 5-15:1.

[0099] In step two, the mixing rate of each substance in the water-soluble component is 100 r / min and the mixing time is 10 min.

[0100] In step three, the mixing rate of each substance in the fiber component and each substance in the whisker component is 150 r / min, and the mixing time is 20 min.

[0101] In step four, polyethylene glycol with molecular weights of 10,000, 12,000, and 14,000 is placed in a mixer at a stirring speed of 200 rpm. After heating to 90°C, stirring continues for 20 minutes. While maintaining the temperature inside the mixer at 90°C, polyethylene glycol with molecular weights of 1,000, 2,000, 6,000, and 8,000 is added to the mixer and stirring continues for 20 minutes. Polyvinyl alcohol and urea are then added to the mixer at a stirring speed of 200 rpm. After raising the temperature to 120°C, stirring continues for 30 minutes.

[0102] In step five, maintain the temperature inside the mixer at 120°C, add all the surfactants into the mixer and continue mixing for 2 hours.

[0103] In step six, maintain the temperature inside the mixer at 120°C, add the composite powder material into the mixer and continue mixing for 2 hours.

[0104] In step seven, the temperature inside the mixer is kept at 120°C, and the fiber-whisker multi-size reinforcing material is added to the mixer and stirred for another 5 hours.

[0105] In step eight, maintain the temperature inside the mixer at 120°C, add the graphene to the mixer and continue mixing for 3 hours.

[0106] The performance of the graphene-whisker composite water-soluble wax materials for investment casting prepared in the above three embodiments was tested, and the test results are shown in Table 1.

[0107] Table 1. Performance test results of graphene-whisker composite water-soluble wax material

[0108]

[0109] The test results above show that the graphene-whisker composite water-soluble wax material for investment casting prepared in the three embodiments has high bending strength, tensile strength, elongation at break and Vicat softening point. It also has excellent water solubility and no alkali metal ion residue after water dissolution. It can fully meet the high performance requirements of wax material for forming complex multi-layered ceramic cores, hollow ceramic cores and complex hollow wax molds in high-temperature alloy investment casting.

[0110] The matrix materials, surfactants, water-soluble components, fiber components, whisker components, and graphene used in the above embodiments were purchased from Aladdin Reagent Co., Ltd. and Sinopharm Chemical Reagent Co., Ltd.

[0111] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant progress of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive experimentation. For each parameter and the combinations thereof, the inventors have recorded a large amount of experimental data; however, due to space limitations, the specific experimental data is not disclosed here.

[0112] It will be readily understood by those skilled in the art that this invention includes any combination of the inventive description and specific embodiments outlined in the foregoing specification and the various parts shown in the accompanying drawings. Due to space limitations and for the sake of brevity, not all of these combinations have been described in detail. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A graphene-whisker composite water-soluble wax material for investment casting, characterized in that: The water-soluble wax material comprises the following components by mass percentage: matrix material 30-47 wt%, surfactant 3.5-9 wt%, water-soluble component 12-26 wt%, fiber component 3-8 wt%, whisker component 8-22 wt%, and graphene 0.5-5 wt%, with the total content of each component being 100 wt%. The matrix material comprises the following mass percentages of each substance: polyethylene glycol 44-65 wt%, polyvinyl alcohol 25-46 wt%, and urea 10-23 wt%. The polyethylene glycol is a compound system designed with a molecular weight gradient, wherein the polyethylene glycol in the low molecular weight range of 1000-2000, the medium molecular weight range of 6000-8000, and the high molecular weight range of 10000-14000 accounts for 40-50 wt%, 30-40 wt%, and 20-30 wt% of the total polyethylene glycol, respectively. In the low molecular weight polyethylene glycol (1000-2000), the mass ratio of polyethylene glycol with a molecular weight of 1000 to that with a molecular weight of 2000 is 2:1; in the medium molecular weight polyethylene glycol (6000-8000), the mass ratio of polyethylene glycol with a molecular weight of 6000 to that with a molecular weight of 8000 is 2:1; and in the high molecular weight polyethylene glycol (10000-14000), the mass ratio of polyethylene glycol with a molecular weight of 10000, 12000, and 14000 is 3:2:

1. The mass percentage of each substance in the fiber component is 18-32 wt% nylon fiber, 28-44 wt% carbon fiber, and 28-44 wt% carboxymethyl cellulose; the diameter of the nylon fiber and the carbon fiber are both controlled within the range of 5-15 μm, and the aspect ratio is controlled within the range of 15-25:

1.

2. The graphene-whisker composite water-soluble wax material for investment casting according to claim 1, characterized in that: The mass percentages of each substance in the surfactant are as follows: stearic acid 22-32 wt%, fatty acid 22-32 wt%, sodium stearate 15-25 wt%, sodium dodecyl sulfate 10-18 wt%, and sodium dodecylbenzene sulfonate 10-18 wt%.

3. The graphene-whisker composite water-soluble wax material for investment casting according to claim 2, characterized in that: The water-soluble components comprise the following mass percentages: sodium chloride 26-38 wt%, sodium bicarbonate 18-30 wt%, ammonium chloride 16-26 wt%, talc 8-18 wt%, and mica powder 8-16 wt%; the median particle size of the talc and mica powder is 1-10 μm.

4. The graphene-whisker composite water-soluble wax material for investment casting according to claim 3, characterized in that: The mass percentages of each substance in the whisker component are as follows: mullite whiskers 18-30 wt%, alumina whiskers 15-26 wt%, silicon oxide whiskers 8-18 wt%, silicon carbide whiskers 8-18 wt%, and organic whiskers 15-26 wt%; the mass percentages of each substance in the organic whiskers are as follows: polyamide whiskers 30-40 wt% and chitosan whiskers 60-70 wt%.

5. The graphene-whisker composite water-soluble wax material for investment casting according to claim 4, characterized in that: The diameters of the mullite whiskers, alumina whiskers, silicon oxide whiskers, and silicon carbide whiskers are all controlled within the range of 1-5 μm, and the aspect ratios are all controlled within the range of 15-25:1; the diameters of the polyamide whiskers and chitin whiskers are all controlled within the range of 0.5-1 μm, and the aspect ratios are all controlled within the range of 5-15:

1.

6. A method for preparing a graphene-whisker composite water-soluble wax material for investment casting according to any one of claims 1-5, characterized in that: The preparation method includes the following steps in sequence: Step 1: Weigh out each raw material according to the designed material ratio and set aside; Step 2: Put all the water-soluble components, including sodium chloride, sodium bicarbonate, ammonium chloride, talc powder, and mica powder, into a V-type mixer and mix them at room temperature for a certain period of time to ensure that the components are mixed evenly, thus obtaining a composite powder material. Take it out for later use. Step 3: Put all the materials in the fiber component (nylon fiber, carbon fiber, carboxymethyl cellulose) and the materials in the whisker component (mullite whiskers, alumina whiskers, silicon dioxide whiskers, silicon carbide whiskers, polyamide whiskers, chitosan whiskers) into a V-type mixer and mix them at room temperature for a certain period of time to make the materials evenly mixed, so as to obtain a fiber-whisker multi-size reinforcing material, which can be taken out for later use. Step 4: Place polyethylene glycols with molecular weights of 10,000, 12,000, and 14,000 from the matrix material into a mixer, and heat while stirring. After heating to a certain temperature, continue stirring for a certain period of time. Keeping the temperature inside the mixer constant, add polyethylene glycols with molecular weights of 1,000, 2,000, 6,000, and 8,000 to the mixer and continue stirring for a certain period of time. Add polyvinyl alcohol and urea from the matrix material into the mixer, and heat while stirring. After heating to a certain temperature, continue stirring for a certain period of time to completely melt all the substances in the matrix material, thus obtaining the initial matrix slurry. Step 5: Keep the temperature inside the mixer constant, add all the surfactants stearic acid, fatty acid, sodium stearate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate into the mixer, and continue stirring for a certain period of time to ensure that the substances are evenly dispersed, thus obtaining the modified matrix slurry. Step Six: Keep the temperature inside the mixer constant, add the composite powder material into the mixer, and continue mixing for a certain period of time to ensure that all substances are completely combined; Step 7: Keep the temperature inside the mixer constant, add the fiber-whisker multi-size reinforcing material into the mixer, and continue mixing for a certain period of time to ensure that the fiber-whisker multi-size reinforcing material is evenly dispersed; Step 8: Keep the temperature inside the mixer constant, add graphene to the mixer, and continue stirring for a certain period of time to ensure that all substances are mixed evenly, thus obtaining the graphene-whisker composite water-soluble wax material. Step 9: The graphene-whisker composite water-soluble wax material is molded, cooled and demolded to obtain an ingot, which is then sealed and stored for subsequent high-temperature alloy investment casting process.

7. The preparation method of the graphene-whisker composite water-soluble wax material for investment casting according to claim 6, characterized in that: In step two, the mixing rate of each substance in the water-soluble component is 50-100 r / min, and the mixing time is 10-15 min. In step three, the mixing rate of each substance in the fiber component and each substance in the whisker component is 100-150 r / min, and the mixing time is 20-30 min. In step four, polyethylene glycol with molecular weights of 10,000, 12,000, and 14,000 is placed in a mixer at a stirring speed of 100-200 rpm. After heating to 70-90°C, stirring continues for 20-50 minutes. While maintaining the temperature in the mixer at 70-90°C, polyethylene glycol with molecular weights of 1,000, 2,000, 6,000, and 8,000 is added to the mixer and stirring continues for 20-50 minutes. Polyvinyl alcohol and urea are then added to the mixer at a stirring speed of 100-200 rpm. After raising the temperature to 100-120°C, stirring continues for 30-80 minutes. In step five, maintain the temperature inside the mixer at 100-120℃, add all the surfactants into the mixer and continue mixing for 2-3 hours; In step six, maintain the temperature inside the mixer at 100-120℃, add the composite powder material into the mixer and continue mixing for 2-3 hours; In step seven, maintain the temperature inside the mixer at 100-120℃, add the fiber-whisker multi-size reinforcing material into the mixer and continue mixing for 5-8 hours; In step eight, maintain the temperature inside the mixer at 100-120℃, add the graphene to the mixer and continue mixing for 3-4 hours.

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