Low-temperature pre-coating wax material and pre-coating wax method for complex structure multi-layer wall ceramic core

Abstract

The application discloses a low-temperature pre-filling wax material for a ceramic core with a complex structure and a multilayer wall and a pre-filling wax method. In the low-temperature pre-filling wax material, the proportions of various substances are as follows: a paraffin component 46-56 wt%, a surfactant 6-9 wt%, a modifier 6-9 wt%, a fiber component 6-10 wt%, a whisker component 5-8 wt%, graphene 1-5 wt%, a biomass component 0.5-1 wt% and a bonding wax 12-22 wt%. The pre-filling wax method comprises the following steps: preparing the low-temperature pre-filling wax material; using a wax injection gun to fill the small-sized area in the ceramic core with wax, removing the excess wax flow after standing, and thus completing the pre-filling wax process of the ceramic core. The pre-filling wax material has small solidification shrinkage, moderate fluidity and high strength, can prevent the material from being broken during the flowing and wax pressing processes, and can be completely removed after the wax pressing mold and the shell are prepared, and no ash residue is left.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of special functional materials for investment precision casting, and particularly relates to a low-temperature pre-wax material for a complex-structure multi-layer-wall ceramic core and a pre-wax method. BACKGROUND

[0002] In the field of high-end equipment manufacturing such as aerospace and gas turbines, a complex-structure multi-layer-wall ceramic core is one of the core process elements for realizing precision casting of key components such as high-performance blades. Such ceramic cores are usually designed as double-layer-wall or even multi-layer-wall structures, and the design purpose is to meet the forming requirements of complex internal cooling channels of the blades, so as to improve the heat dissipation performance and working reliability of the blades in a high-temperature environment. However, the multi-layer-wall ceramic core still faces many severe challenges in actual production and application.

[0003] Firstly, the structure of the multi-layer-wall ceramic core is extremely complex, with thin walls (usually 0.5-2 mm) and low overall strength (bending strength of 10-20 MPa). During production circulation (such as handling, storage, and transfer), even slight collisions, vibrations, or clamping operations can cause cracks or even breakage of the core. According to industry statistics, the breakage rate of double-layer-wall ceramic cores without pre-strengthening treatment during the circulation link is as high as 30-50%, seriously affecting production efficiency and manufacturing cost. However, the pre-wax material of the existing technology has insufficient strength (compressive strength at room temperature is less than 5 MPa), and cannot effectively pre-fill and reinforce the weak positions of the core (such as double-layer gaps, channel corner positions, etc.), thereby resulting in a high scrap rate of the core.

[0004] Secondly, the multi-layer-wall ceramic core has a large number of hollow structures and hollow parts, and in the subsequent wax pressing forming process, these areas become weak points that are easily damaged due to lack of sufficient support. In the wax pressing process, the wax liquid needs to be injected into the cavity under a certain pressure, and in the traditional process, the injection pressure of the wax liquid (usually 0.8-2 MPa) is extremely easy to cause deformation, crushing or collapse of the hollow parts and hollow structures due to the lack of support inside the core, thereby causing the overall breakage of the core and resulting in scrap. According to industry statistics, the scrap rate of ceramic cores of aircraft engine blades due to wax pressing pressure accounts for more than 40% of the total scrap.

[0005] Thirdly, the structure size of key positions such as impact holes (usually 1-3 mm in diameter) and transverse ribs (usually 2-5 mm in width) on the multilayer wall ceramic core is small. If pre-waxing treatment is not performed, there will be significant differences in the wax filling thickness (the thickness difference can be 3-10 times) at the wax mold forming stage after wax pressing, which will generate uneven shrinkage stress and easily cause excessive shrinkage, exceeding the dimensional accuracy requirement (usually ±0.05 mm) of the blade, resulting in dimensional tolerance of the profile, and in severe cases, the blade cannot meet the assembly and use performance requirements. The probability of such problems occurring in the production of complex profile blades is more than 25%.

[0006] At present, the pre-waxing materials used in the prior art are mainly single-component paraffin wax or beeswax. The shrinkage of such wax is large, the linear shrinkage rate of paraffin wax can reach 1.5-3%, and the linear shrinkage rate of beeswax is also between 1-2%. When the wax is pre-filled into the ceramic core, the shrinkage stress generated during the solidification process far exceeds the bearing limit of the ceramic core, thereby causing the core to be cracked or fractured. In addition, the flowability of single wax is unstable and difficult to control. Either the wax is too thin, causing dripping during the wax injection process and contaminating the core surface, or the wax is too thick, causing the wax injection gun to be blocked and unable to smoothly fill the gaps and holes of small structures. At the same time, the strength of these traditional waxes is low (the compressive strength at room temperature is less than 5 MPa), which cannot provide effective structural support for the core and is difficult to prevent the core from being broken during the flow and pressing process.

[0007] In addition, the pre-waxing operation of the prior art lacks targeted process parameters. For example, the injection temperature, pressure, speed and other process parameters are not reasonable, which leads to poor filling effect of complex and small positions such as double-layer gaps, channel gaps, impact holes, etc. Either the filling is not full and forms a hollow, or the filling is excessive, causing wax waste and difficult to clean, affecting the subsequent process.

[0008] In summary, the pre-waxing material and wax filling process of the prior art cannot meet the production needs of complex structure multilayer wall ceramic cores. Therefore, developing a new type of pre-waxing material with low shrinkage, appropriate flowability, high strength and easy removal, as well as a pre-waxing method matched therewith, has become the key to solving the current industry technical bottleneck and promoting the development of precision casting technology. SUMMARY

[0009] To solve the problems in the prior art, the application provides a low-temperature pre-filling wax material for a ceramic core with a complex structure and a multi-layer wall, wherein the mass percentage of each substance in the low-temperature pre-filling wax material is as follows: 46-56 wt% of a paraffin component, 6-9 wt% of a surfactant, 6-9 wt% of a modifier, 6-10 wt% of a fiber component, 5-8 wt% of a whisker component, 1-5 wt% of graphene, 0.5-1 wt% of a biomass component, and 12-22 wt% of a bonding wax, and the sum of the contents of the substances is 100 wt%.

[0010] Preferably, the mass percentage of each substance in the paraffin component is as follows: 46# semi-refined paraffin 10-15 wt%, 48# fully refined paraffin 15-21 wt%, 52# fully refined paraffin 19-25 wt%, 58# fully refined paraffin 19-25 wt%, and 60# fully refined paraffin 22-27 wt%.

[0011] Preferably in any of the above solutions, the mass percentage of each substance in the surfactant is as follows: stearic acid 40-53 wt%, fatty acid 25-39 wt%, and sodium dodecyl benzene sulfonate 13-27 wt%.

[0012] Preferably in any of the above solutions, the mass percentage of each substance in the modifier is as follows: beeswax 66-80 wt% and polyethylene wax 20-34 wt%.

[0013] Preferably in any of the above solutions, the mass percentage of each substance in the fiber component is as follows: short-cut carbon fiber 30-43 wt%, short-cut nylon fiber 28-40 wt%, and short-cut aramid fiber 25-37 wt%; the diameter of the short-cut carbon fiber, the short-cut nylon fiber and the short-cut aramid fiber is controlled in the range of 5-15 μm, and the aspect ratio of the short-cut carbon fiber, the short-cut nylon fiber and the short-cut aramid fiber is controlled in the range of 15-25:1.

[0014] Preferably in any of the above solutions, the mass percentage of each substance in the whisker component is as follows: polyamide whisker 25-30 wt%, chitin whisker 35-40 wt%, and cellulose whisker 35-40 wt%; the diameter of the polyamide whisker, the chitin whisker and the cellulose whisker is controlled in the range of 0.5-1 μm, and the aspect ratio of the polyamide whisker, the chitin whisker and the cellulose whisker is controlled in the range of 5-15:1.

[0015] Preferably in any of the above schemes, the mass percentage of each substance in the biomass component is 35-50wt% of soybean oil, 25-38wt% of chlorella powder, and 22-35wt% of spirulina powder; the chlorella powder and the spirulina powder each include three grades of particle sizes, namely, a particle size of 18-30μm, a particle size of 5-18μm, and a particle size of 0-5μm, and the mass ratio of the particle size of 18-30μm, the particle size of 5-18μm, and the particle size of 0-5μm is 1:1.5-2:2.5-3.

[0016] The application also provides a pre-waxing method for a complex-structure multi-layer-wall ceramic core, which adopts the low-temperature pre-waxing material for the complex-structure multi-layer-wall ceramic core described in any of the above schemes, and comprises the following steps in sequence:

[0017] Step one: preparing the low-temperature pre-waxing material according to the designed process flow and process parameters;

[0018] Step two: loading the prepared low-temperature pre-waxing material into a wax injection gun, and controlling the temperature of the low-temperature pre-waxing material in the wax injection gun to keep a proper fluidity, so as to ensure the smoothness of the subsequent wax injection operation;

[0019] Step three: injecting the wax into the size-thin area of the complex-structure multi-layer-wall ceramic core according to the designed process parameters by using the wax injection gun, and after a certain period of standing, cleaning the escaped excess wax flow by using a tool after the escaped wax flow is preliminarily solidified, so as to complete the pre-waxing process of the complex-structure multi-layer-wall ceramic core and simultaneously prepare the pre-waxing complex-structure multi-layer-wall ceramic core.

[0020] Preferably, in step one, the preparation method of the low-temperature pre-waxing material comprises the following steps in sequence:

[0021] Step 1.1: weighing each raw material according to the designed material ratio for standby;

[0022] Step 1.2: putting each substance of the fiber component, i.e., the short-cut carbon fiber, the short-cut nylon fiber, the short-cut aramid fiber, and each substance of the whisker component, i.e., the polyamide whisker, the chitin whisker, and the cellulose whisker, into a V-shaped mixer, mixing them at room temperature for 20-30min at a mixing speed of 100-200r / min, so as to disperse each substance uniformly and obtain a fiber-whisker multi-size reinforcing material, and taking it out for standby;

[0023] Step 1.3: putting each grade of chlorella powder and spirulina powder into a V-shaped mixer, mixing them at room temperature for 10-20min at a mixing speed of 100-200r / min, so as to mix each substance uniformly and obtain a composite algae powder, and taking it out for standby;

[0024] Step 1.4: Put all the substances in the surfactant, stearic acid, fatty acid, sodium dodecyl benzene sulfonate, into a blender, stir while heating, the stirring speed is 300-400 r / min, continue to stir for 30-40 min after heating to 90-110℃, so that the substances are fused with each other, and the surfactant is obtained, and then taken out for storage;

[0025] Step 1.5: Put all the substances in the paraffin component, 46# semi-refined paraffin wax, 48# fully refined paraffin wax, 52# fully refined paraffin wax, 58# fully refined paraffin wax, 60# fully refined paraffin wax, into a blender, stir while heating, the stirring speed is 200-300 r / min, continue to stir for 20-30 min after heating to 80-95℃, so that the substances are completely melted;

[0026] Step 1.6: Keep the stirring temperature and stirring speed unchanged, add 80-90 wt% of the surfactant into the blender and continue to stir for 1-2 h, so that the substances are fused with each other;

[0027] Step 1.7: Keep the stirring temperature and stirring speed unchanged, add the bonding wax into the blender and continue to stir for 20-30 min, so that the substances are fused with each other;

[0028] Step 1.8: Keep the stirring temperature and stirring speed unchanged, add all the substances in the modifier, beeswax, polyethylene wax, into the blender and continue to stir for 1-2 h, so that the substances are fused with each other;

[0029] Step 1.9: Keep the stirring temperature and stirring speed unchanged, add 10-20 wt% of the surfactant and soybean oil in the biomass component into the blender and continue to stir for 1-2 h, so that the substances are fused with each other;

[0030] Step 1.10: Keep the stirring temperature and stirring speed unchanged, add the fiber-whisker multi-size reinforcing material and composite algal powder into the blender and continue to stir for 3-5 h, so that the substances are mixed uniformly;

[0031] Step 1.11: Keep the stirring temperature and stirring speed unchanged, add the graphene into the blender and continue to stir for 5-8 h, so that the substances are mixed uniformly, and the low-temperature pre-filling wax material is prepared;

[0032] Step 1.12: The prepared low-temperature pre-filling wax material is injection molded, and the ingot is obtained after cooling and demolding, and is sealed and stored for subsequent pre-filling wax process of complex structure multi-layer wall ceramic core.

[0033] In any of the above schemes, it is preferred that in step two, the temperature of the low-temperature pre-filling wax material in the wax injection gun is controlled to be 60-75℃.

[0034] In any of the above schemes, preferably, in step three, the size small area in the complex structure multilayer wall ceramic core includes double-layer gap, channel gap, transverse rib, cover plate and impact hole; the wax injection pressure is 0.2-0.5 MPa, the wax injection speed is 5-15 ml / s, and the straight line distance between the gun head of the wax injection gun and the filling position is 5-15 mm.

[0035] For the double-layer gap and the channel gap, the wax injection gun is moved at a uniform speed along the length direction of the gap, and the moving speed is 10-30 mm / s; for the transverse rib and the cover plate, a plurality of wax injection points are selected, the wax injection amount of each wax injection point is 0.5-2 ml / time, and each wax injection point is repeated for several times; for the impact hole, the gun head of the wax injection gun is aimed at the center of the impact hole, and the wax is injected vertically to the hole end face until the wax material protrudes from the hole end face. After the wax injection, the tool is used to clean the escaped excess wax flow after 1-3 min.

[0036] In the application, the V-shaped mixer, the stirrer (heating type), the wax injection gun and the like used are all conventional devices, and there is no special requirement for the device structure and model. The chlorella powder and the spirulina powder used all include three grades of particle sizes, which are particle size 18-30 μm, particle size 5-18 μm and particle size 0-5 μm, i.e. 18 μm≤particle size≤30 μm, 5 μm≤particle size<18 μm and 0 μm<particle size<5 μm. For each grade of particle size, the material obtained after the material sequentially passes through the upper and lower two screen holes has a particle size between the upper and lower two screen holes, for example, the material obtained after the material sequentially passes through the 18 μm screen hole and the 5 μm screen hole has a particle size between 5 μm and 18 μm. For the cellulose whisker, the cellulose whisker with a diameter and a length-diameter ratio meeting the requirements of the application can be directly purchased, and there is no special requirement for the type, model and preparation of the cellulose whisker.

[0037] The application innovatively introduces trace biological material, including soybean oil, chlorella powder and spirulina powder. The soybean oil can be well compatible with the wax matrix, can improve the filling fluidity, and can improve the wettability, especially the soybean oil can improve the interface wettability between the pre-filled wax material and the inner wall of the ceramic core mold, avoid the formation of shrinkage holes or bubbles on the mold surface due to the repulsion of the molten wax, and thus ensure the close fit between the wax layer and the mold after filling, so that the subsequent forming is more complete. The addition of chlorella powder and spirulina powder can not only enhance the forming stability, but also realize efficient dewaxing, especially the chlorella powder and spirulina powder can form micro-channels in the wax matrix, and after the algae powder is dispersed, fine pores or channels are constructed in the wax layer. The molten wax can quickly volatilize through these pores or channels when heated, and the gas generated by the decomposition of the algae powder itself can also push the residual wax out, thereby realizing efficient dewaxing.

[0038] For soybean oil, a small amount of surfactant needs to be added at the same time when adding into the blender, so that the soybean oil can be better combined with the paraffin wax, and a stable dispersion system is provided for the subsequent addition of fiber components, whisker components, algal powder and graphene.

[0039] For chlorella powder and spirulina powder, three grades of algal powder with particle sizes of 18-30 μm, 5-18 μm and 0-5 μm can be directly purchased and used, and the algal powder needs to be dried without moisture or with a very low moisture content (not more than 1%).

[0040] More preferably, algal powder with a particle size in the range of 50-80 μm is purchased, and the coarse particle size algal powder is pretreated to obtain algal powder with three grades of particle sizes according to the present application.

[0041] Firstly, the coarse particle size chlorella powder and spirulina powder are placed in a drying oven for drying treatment, the drying temperature is 100-120℃, and the drying time is 1-2h, and then the dried powder is taken out and naturally cooled to room temperature.

[0042] Then, the dried chlorella powder and spirulina powder are placed in a muffle furnace for gradient calcination treatment, i.e. the temperature is increased from room temperature to 200-300℃ (200℃≤temperature<300℃) at a rate of 5-10℃ / min, and the temperature is kept for 20-30min to slowly remove the residual trace amount of water and volatile small molecular organic matter; the temperature is further increased to 300-500℃ (300℃≤temperature<500℃) at a rate of 3-5℃ / min, and the temperature is kept for 50-60min to slowly remove organic matter such as protein and polysaccharide; the temperature is further increased to 500-650℃ (500℃≤temperature<650℃) at a rate of 5-10℃ / min, and the temperature is kept for 20-30min, and then the furnace is cooled to room temperature, and the residual organic matter is completely removed.

[0043] Finally, the calcined chlorella powder and spirulina powder are ground and sieved to meet the particle size grades of the present application.

[0044] The low-temperature pre-filling wax material and the pre-filling wax method for the ceramic core with a complex structure and a multi-layer wall have the following beneficial effects:

[0045] (1) The pre-filled wax material of the present application has small solidification shrinkage, and the linear shrinkage rate can be controlled below 0.5%. This is because the reasonable proportioning of various waxes and the synergistic effect of various additives can prevent the wax filled into the multi-layer wall core from generating excessive stress on the core during solidification, thereby avoiding the breakage of the core.

[0046] (2) The pre-filled wax material of the present application has moderate flowability, and the viscosity can be controlled at 500-1500 mPa・s (at 60℃). By adjusting the waxes with different melting points and properties and related components, the wax can be injected by using a wax injection gun, without causing wax dripping due to too thin wax liquid or wax blocking due to too thick wax liquid, thereby ensuring the smooth filling process.

[0047] (3) The pre-filled wax material of the present application has high strength, and the compressive strength at room temperature can be above 8 MPa. The reinforcing materials such as fiber components and whisker components combined with the wax matrix can effectively reinforce the ceramic core and significantly improve the anti-fracture ability of the ceramic core during the transfer or wax pressing process. According to the actual test, the breakage rate of the ceramic core treated by the pre-filled wax material of the present application can be reduced to below 5%, and the breakage rate during the wax pressing process can be controlled within 10%. (4) After the wax pressing mold and the shell are prepared, the pre-filled wax material of the present application can be completely removed by dewaxing (120-160℃) and baking (800-1200℃), and the residual ash content is below 0.01%, so that the inclusion defect rate of the blade can be reduced to below 0.5%, thereby ensuring the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 A photo of the low-temperature pre-filled wax material prepared according to the preferred embodiment of the low-temperature pre-filled wax material for the complex structure multi-layer wall ceramic core and the pre-filled wax method of the present application;

[0049] Figure 2 A photo of the pre-filled wax for the double-layer gap according to the embodiment shown in Figure 1

[0050] Figure 3 A photo of the pre-filled wax for the channel gap according to the embodiment shown in Figure 1

[0051] A photo of the ceramic core surface after wax injection without wax cleaning according to the embodiment shown in Figure 4 Figure 1

[0052] Figure 5 Figure 1

[0053] Figure 6 ​​​​​For Figure 1 The partial photo of the surface of the ceramic core after wax injection and wax removal in the embodiment shown in the figure; Figure 7 For Figure 1 The X-ray detection photo of the wax mold pressed after pre-filling wax in the embodiment shown in the figure. DETAILED DESCRIPTION

[0054] In order to further understand the inventive content of the present application, the present application will be described in detail below in combination with specific embodiments.

[0055] Embodiment one:

[0056] According to a preferred embodiment of the low-temperature pre-filling wax material for the ceramic core with complex structure and multi-layer wall of the present application, the mass percentage of each substance in the low-temperature pre-filling wax material is as follows: paraffin component 50wt%, surfactant 8wt%, modifier 7wt%, fiber component 8wt%, whisker component 6.2wt%, graphene 3wt%, biomass component 0.8wt%, and bonding wax 17wt%.

[0057] The mass percentage of each substance in the paraffin component is as follows: 46# semi-refined paraffin 13wt%, 48# fully refined paraffin 18wt%, 52# fully refined paraffin 22wt%, 58# fully refined paraffin 22wt%, and 60# fully refined paraffin 25wt%.

[0058] The mass percentage of each substance in the surfactant is as follows: stearic acid 48wt%, fatty acid 32wt%, and sodium dodecyl benzene sulfonate 20wt%. The mass percentage of each substance in the modifier is as follows: beeswax 73wt% and polyethylene wax 27wt%.

[0059] The mass percentage of each substance in the fiber component is as follows: short-cut carbon fiber 36wt%, short-cut nylon fiber 34wt%, and short-cut aramid fiber 30wt%; the diameter of the short-cut carbon fiber, the short-cut nylon fiber, and the short-cut aramid fiber is controlled within the range of 5-15μm, and the aspect ratio is controlled within the range of 15-25:1.

[0060] The mass percentage of each substance in the whisker component is as follows: polyamide whisker 25wt%, chitin whisker 40wt%, and cellulose whisker 35wt%; the diameter of the polyamide whisker, the chitin whisker, and the cellulose whisker is controlled within the range of 0.5-1μm, and the aspect ratio is controlled within the range of 5-15:1.

[0061] The mass percentage of each substance in the biomass component is 41wt% of soybean oil, 31wt% of chlorella powder, and 28wt% of spirulina powder; the chlorella powder and the spirulina powder each include three grades of particle sizes, namely, a particle size of 18-30μm, a particle size of 5-18μm, and a particle size of 0-5μm, and the mass ratio of the particle size of 18-30μm, the particle size of 5-18μm, and the particle size of 0-5μm is 1:1.8:2.8.

[0062] The embodiment also provides a pre-waxing method for a complex-structure multi-layer-wall ceramic core, which adopts the low-temperature pre-waxing material for the complex-structure multi-layer-wall ceramic core, and the pre-waxing method includes the following steps in sequence:

[0063] Step one: preparing the low-temperature pre-waxing material according to the designed process flow and process parameters;

[0064] Step two: loading the prepared low-temperature pre-waxing material into a wax injection gun, and controlling the temperature of the low-temperature pre-waxing material in the wax injection gun to keep the proper fluidity, so as to ensure the smooth subsequent wax injection operation;

[0065] Step three: according to the designed process parameters, using the wax injection gun to inject and fill the small-size area in the complex-structure multi-layer-wall ceramic core, and after a certain period of standing after the wax injection, using a tool to clean the escaped excess wax flow after the escaped wax flow is preliminarily solidified, thus completing the pre-waxing process of the complex-structure multi-layer-wall ceramic core and simultaneously preparing the pre-waxing complex-structure multi-layer-wall ceramic core.

[0066] In step one, the preparation method of the low-temperature pre-waxing material includes the following steps in sequence:

[0067] Step 1.1: weighing each raw material according to the designed material ratio for standby;

[0068] Step 1.2: putting all the substances, i.e., the short-cut carbon fiber in the fiber component, the short-cut nylon fiber, the short-cut aramid fiber, and the substances, i.e., the polyamide whisker, the chitin whisker, and the cellulose whisker in the whisker component, into a V-shaped mixer, mixing at room temperature for 25min at a mixing speed of 150r / min, so as to uniformly disperse the substances, and obtaining the fiber-whisker multi-size reinforcing material for standby;

[0069] Step 1.3: putting all the chlorella powder and spirulina powder of each grade of particle size into a V-shaped mixer, mixing at room temperature for 15min at a mixing speed of 150r / min, so as to uniformly mix the substances, and obtaining the composite algal powder for standby;

[0070] Step 1.4: Put all the substances in the surfactant, stearic acid, fatty acid, sodium dodecyl benzene sulfonate, into a blender, stir while heating, the stirring speed is 350 r / min, continue to stir for 35 min after the temperature is heated to 100℃, so that the substances are fused with each other, and the surfactant is obtained, and then taken out for storage;

[0071] Step 1.5: Put all the substances in the paraffin component, 46# semi-refined paraffin wax, 48# fully refined paraffin wax, 52# fully refined paraffin wax, 58# fully refined paraffin wax, 60# fully refined paraffin wax, into a blender, stir while heating, the stirring speed is 250 r / min, continue to stir for 25 min after the temperature is heated to 88℃, so that the substances are completely melted;

[0072] Step 1.6: Keep the stirring temperature and stirring speed unchanged, add 85wt% of the surfactant into the blender and continue to stir for 1.5h, so that the substances are fused with each other;

[0073] Step 1.7: Keep the stirring temperature and stirring speed unchanged, add the bonding wax into the blender and continue to stir for 25 min, so that the substances are fused with each other;

[0074] Step 1.8: Keep the stirring temperature and stirring speed unchanged, add all the substances in the modifier, beeswax, polyethylene wax, into the blender and continue to stir for 1.5h, so that the substances are fused with each other;

[0075] Step 1.9: Keep the stirring temperature and stirring speed unchanged, add 15wt% of the surfactant and soybean oil in the biomass component into the blender and continue to stir for 1.5h, so that the substances are fused with each other;

[0076] Step 1.10: Keep the stirring temperature and stirring speed unchanged, add the fiber-whisker multi-size reinforcing material, composite algal powder into the blender and continue to stir for 4h, so that the substances are mixed uniformly;

[0077] Step 1.11: Keep the stirring temperature and stirring speed unchanged, add the graphene into the blender and continue to stir for 6.5h, so that the substances are mixed uniformly, and the low-temperature pre-filling wax material is prepared;

[0078] Step 1.12: The prepared low-temperature pre-filling wax material is injection molded, and the ingot is obtained after cooling and demolding, and is sealed and stored for subsequent pre-filling wax process of complex structure multi-layer wall ceramic core.

[0079] In step two, the temperature of the low-temperature pre-filling wax material in the wax injection gun is controlled to be 68℃.

[0080] In step three, the size small area in the complex structure multilayer wall ceramic core includes double-layer gap, channel gap, transverse rib, cover plate and impact hole; the wax injection pressure is 0.4 MPa, the wax injection speed is 10 ml / s, and the straight line distance between the gun head of the wax injection gun and the filling position is 10 mm.

[0081] For the double-layer gap and the channel gap, the wax injection gun is moved at a uniform speed along the length direction of the gap, and the moving speed is 20 mm / s; for the transverse rib and the cover plate, a plurality of wax injection points are selected, the wax injection amount of each wax injection point is 1.2 ml / time, and each wax injection point is repeatedly injected for several times; for the impact hole, the gun head of the wax injection gun is aimed at the center of the impact hole, and the wax is injected vertically to the hole end face until the wax material protrudes from the hole end face. After the wax injection, the escaped excess wax flow is cleaned with a tool after standing for 2 min.

[0082] For the chlorella powder and the spirulina powder, the three-grade particle size algae powders meeting the requirements of the embodiment can be directly purchased, and the algae powders need to be dried to ensure that the moisture content is low (not more than 1%). It is more preferred in the embodiment that the algae powders with a particle size in the range of 50-80 μm are purchased, and the coarse particle size algae powders are pretreated to obtain the three-grade particle size algae powders meeting the requirements of the embodiment. The coarse particle size algae powders are pretreated according to the following method.

[0083] Firstly, the coarse particle size chlorella powders and spirulina powders are respectively placed in a drying oven for drying treatment, the drying temperature is 110 ℃, the drying time is 1.5 h, and the powders are taken out and naturally cooled to room temperature after drying.

[0084] Then, the dried chlorella powders and spirulina powders are respectively placed in a muffle furnace for gradient calcination treatment, that is, the temperature is increased to 250 ℃ from room temperature at a heating rate of 8 ℃ / min, and the temperature is kept for 25 min to slowly remove the trace amount of residual moisture and remove the small molecule organic matter which is easy to volatilize; the temperature is continuously increased to 400 ℃ at a heating rate of 4 ℃ / min, and the temperature is kept for 55 min to slowly remove the organic matter such as protein and polysaccharide; the temperature is continuously increased to 570 ℃ at a heating rate of 8 ℃ / min, and the temperature is kept for 25 min, and then the furnace is cooled to room temperature, and the residual organic matter is completely removed.

[0085] Finally, the calcined chlorella powders and spirulina powders are respectively ground and sieved to obtain the particle size grades meeting the requirements of the embodiment.

[0086] In the embodiment, the prepared low-temperature pre-filled wax material is as shown in Figure 1 The ingot obtained by injection molding of the low-temperature pre-filled wax material is as shown in Figure 2 The pre-filled wax operation for the double-layer gap is as shown in Figure 3 The pre-filled wax operation for the channel gap is as shown in Figure 4The surface of the ceramic core after wax injection is shown in Fig. 3. The surface of the ceramic core after wax removal is shown in Fig. 4. The waxed ceramic core is shown in Fig. 5. Figure 5 The surface of the ceramic core after wax injection is shown in Fig. 3. The surface of the ceramic core after wax removal is shown in Fig. 4. The waxed ceramic core is shown in Fig. 5. Figure 6 The surface of the ceramic core after wax injection is shown in Fig. 3. The surface of the ceramic core after wax removal is shown in Fig. 4. The waxed ceramic core is shown in Fig. 5. Figure 7 The surface of the ceramic core after wax injection is shown in Fig. 3. The surface of the ceramic core after wax removal is shown in Fig. 4. The waxed ceramic core is shown in Fig. 5.

[0087] The low-temperature pre-waxing material for the complex structure multi-layer wall ceramic core and the pre-waxing method have the following beneficial effects: (1) The solidification shrinkage of the pre-waxing material is small, so that the wax filled into the multi-layer wall core will not generate excessive stress on the core during solidification, thereby avoiding the breakage of the core; (2) The flowability of the pre-waxing material is moderate, so that the wax can be injected by using a wax injection gun, without causing wax dripping due to too thin wax liquid or wax blocking due to too thick wax liquid, thereby ensuring the smooth filling process; (3) The strength of the pre-waxing material is high, which can effectively reinforce the ceramic core while preventing excessive shrinkage of the wax mold, thereby significantly improving the anti-breakage capability of the ceramic core during the circulation or wax pressing process; and (4) The pre-waxing material can be completely removed after the wax mold is pressed and the shell is made, with low residual ash content and low blade inclusion defect rate.

[0088] Example Two

[0089] According to another preferred embodiment of the low-temperature pre-waxing material for the complex structure multi-layer wall ceramic core and the pre-waxing method, the material selection and ratio, the process flow and parameters, the technical principle, and the beneficial effects are basically the same as those of Example One, except that:

[0090] The mass percentage of each substance in the low-temperature pre-waxing material is 46wt% of paraffin component, 9wt% of surfactant, 6wt% of modifier, 6wt% of fiber component, 5.5wt% of whisker component, 5wt% of graphene, 0.5wt% of biomass component, and 22wt% of bonding wax.

[0091] The mass percentage of each substance in the paraffin component is 11wt% of 46# semi-refined paraffin, 21wt% of 48# fully refined paraffin, 20wt% of 52# fully refined paraffin, 25wt% of 58# fully refined paraffin, and 23wt% of 60# fully refined paraffin.

[0092] The mass percentage of each substance in the surfactant is 40wt% of stearic acid, 36wt% of fatty acid, and 24wt% of sodium dodecyl benzene sulfonate. The mass percentage of each substance in the modifier is 66wt% of beeswax and 34wt% of polyethylene wax.

[0093] The mass percentage of each substance in the fiber component is 30wt% of chopped carbon fiber, 37wt% of chopped nylon fiber, and 33wt% of chopped aramid fiber. The mass percentage of each substance in the whisker component is 27wt% of polyamide whisker, 35wt% of chitin whisker, and 38wt% of cellulose whisker.

[0094] The mass percentage of each substance in the biomass component is 35wt% of soybean oil, 33wt% of chlorella powder, and 32wt% of spirulina powder; the chlorella powder and the spirulina powder each include three grades of particle size, and the mass ratio of the particle size 18-30μm, the particle size 5-18μm, and the particle size 0-5μm is 1:1.5:2.5.

[0095] In step one, the preparation method of the low-temperature pre-filling wax material includes the following main parameters: step 1.2: placing each substance in the fiber component and each substance in the whisker component into a V-type mixer, mixing at room temperature for 20min, and mixing at a speed of 200r / min to obtain a fiber-whisker multi-size reinforcing material; step 1.3: placing the chlorella powder and the spirulina powder into the V-type mixer, mixing at room temperature for 10min, and mixing at a speed of 200r / min to obtain a composite algae powder; step 1.4: placing each substance in the surfactant into a blender, stirring while heating, stirring at a speed of 300r / min, continuing to stir for 30min after the temperature is heated to 90℃ to obtain a surfactant; step 1.5: placing each substance in the paraffin component into the blender, stirring while heating, stirring at a speed of 200r / min, continuing to stir for 20min after the temperature is heated to 80℃; and steps 1.6-1.11: keeping the stirring temperature and stirring speed unchanged, adding 80wt% of the surfactant to continue stirring for 1h, adding the bonding wax to continue stirring for 20min, adding each substance in the modifier to continue stirring for 1h, adding 20wt% of the surfactant and the soybean oil to continue stirring for 1h, adding the fiber-whisker multi-size reinforcing material and the composite algae powder to continue stirring for 3h, and adding the graphene to continue stirring for 5h to obtain the low-temperature pre-filling wax material.

[0096] In step two, the temperature of the low-temperature pre-filling wax material in the wax injection gun is controlled to be 60℃.

[0097] In step three, the wax injection pressure is 0.2MPa, the wax injection speed is 15ml / s, the straight-line distance between the head of the wax injection gun and the filling position is 5mm, the moving speed of the wax injection gun is 10mm / s when injecting wax into the double-layer gap and the channel gap, and the wax injection amount of each wax injection point is 0.5ml / time when injecting wax into the horizontal rib and the cover plate. After wax injection, the excess wax flow is cleaned after standing for 1min.

[0098] For Chlorella powder and Spirulina powder, the algal powder with a particle size in the range of 50-80 pm was purchased for pretreatment, and the pretreatment process included the following main parameters: (1) the drying temperature was 100 DEG C, and the drying time was 2 h. (2) the residual trace moisture and small molecule organic matter were slowly removed by increasing the temperature from room temperature to 200 DEG C at a temperature increasing rate of 5 DEG C / min and keeping the temperature for 30 min; the organic matter was slowly removed by continuing to increase the temperature to 300 DEG C at a temperature increasing rate of 3 DEG C / min and keeping the temperature for 60 min; and the residual organic matter was completely removed by continuing to increase the temperature to 500 DEG C at a temperature increasing rate of 5 DEG C / min and keeping the temperature for 30 min.

[0099] Example Three

[0100] According to another preferred embodiment of the low-temperature pre-filling wax material and pre-filling wax method for complex structure multi-layer wall ceramic cores, the material selection and ratio, process flow and parameters, technical principle, and beneficial effects are basically the same as those of example one, except that:

[0101] The mass percentage of each substance in the low-temperature pre-filling wax material is 53wt% of paraffin component, 6wt% of surfactant, 9wt% of modifier, 10wt% of fiber component, 8wt% of whisker component, 1wt% of graphene, 1wt% of biomass component, and 12wt% of bonding wax.

[0102] The mass percentage of each substance in the paraffin component is 15wt% of 46# semi-refined paraffin, 15wt% of 48# fully refined paraffin, 25wt% of 52# fully refined paraffin, 19wt% of 58# fully refined paraffin, and 26wt% of 60# fully refined paraffin.

[0103] The mass percentage of each substance in the surfactant is 53wt% of stearic acid, 29wt% of fatty acid, and 18wt% of sodium dodecyl benzene sulfonate. The mass percentage of each substance in the modifier is 80wt% of beeswax and 20wt% of polyethylene wax.

[0104] The mass percentage of each substance in the fiber component is 43wt% of chopped carbon fiber, 30wt% of chopped nylon fiber, and 27wt% of chopped aramid fiber. The mass percentage of each substance in the whisker component is 26wt% of polyamide whisker, 38wt% of chitin whisker, and 36wt% of cellulose whisker.

[0105] The mass percentage of each substance in the biomass component is 50wt% of soybean oil, 25wt% of chlorella powder, and 25wt% of spirulina powder; the chlorella powder and the spirulina powder each include three grades of particle sizes, and the mass ratio of the particle sizes 18-30μm, the particle sizes 5-18μm, and the particle sizes 0-5μm is 1:2:3.

[0106] In step one, the preparation method of the low-temperature pre-filled wax material includes the following main parameters: step 1.2: placing each substance in the fiber component and each substance in the whisker component into a V-type mixer, mixing at room temperature for 30min, and mixing at a speed of 100r / min to obtain a fiber-whisker multi-size reinforcing material; step 1.3: placing the chlorella powder and the spirulina powder into the V-type mixer, mixing at room temperature for 20min, and mixing at a speed of 100r / min to obtain a composite algae powder; step 1.4: placing each substance in the surfactant into a blender, stirring while heating, stirring at a speed of 400r / min, and continuing to stir for 40min after the temperature is heated to 110℃ to obtain a surfactant; step 1.5: placing each substance in the paraffin component into the blender, stirring while heating, stirring at a speed of 300r / min, and continuing to stir for 30min after the temperature is heated to 95℃; steps 1.6-1.11: keeping the stirring temperature and the stirring speed unchanged, adding 90wt% of the surfactant to continue stirring for 2h, adding the bonding wax to continue stirring for 30min, adding each substance in the modifier to continue stirring for 2h, adding 10wt% of the surfactant and the soybean oil to continue stirring for 2h, adding the fiber-whisker multi-size reinforcing material and the composite algae powder to continue stirring for 5h, and adding the graphene to continue stirring for 8h to obtain the low-temperature pre-filled wax material.

[0107] In step two, the temperature of the low-temperature pre-filled wax material in the wax injection gun is controlled to be 75℃.

[0108] In step three, the wax injection pressure is 0.5MPa, the wax injection speed is 5ml / s, the straight-line distance between the gun head of the wax injection gun and the filling position is 15mm, the moving speed of the wax injection gun is 30mm / s when injecting wax into the double-layer gap and the channel gap, and the wax injection amount of each wax injection point is 2ml / time when injecting wax into the horizontal rib and the cover plate. After wax injection, the excess wax flow is cleaned after standing for 3min.

[0109] For Chlorella powder and Spirulina powder, the algal powder with a particle size in the range of 50-80 μm was purchased for pretreatment, and the pretreatment process included the following main parameters: (1) the drying temperature was 120 ℃, and the drying time was 1 h. (2) The temperature was increased from room temperature to 290 ℃ at a rate of 10 ℃ / min, and the temperature was kept for 20 min to slowly remove trace amounts of residual moisture and small molecule organic matter; the temperature was continued to increase to 490 ℃ at a rate of 5 ℃ / min, and the temperature was kept for 50 min to slowly remove organic matter; the temperature was continued to increase to 640 ℃ at a rate of 10 ℃ / min, and the temperature was kept for 20 min to completely remove residual organic matter.

[0110] Comparative Example 1

[0111] Pure paraffin wax was used as the pre-filling wax material, containing 100 wt% of 58# fully refined paraffin wax. The pre-filling wax method: the paraffin wax was placed in a container and heated to 85-95 ℃ to melt; the melted paraffin wax was placed in a wax injection gun, and the temperature was kept at 70-80 ℃; the wax injection gun was used to fill the small positions of the double-layer wall ceramic core, the wax injection pressure was 0.3-0.4 MPa, and the wax injection speed was 8-12 ml / s; after wax injection, 2-3 min was waited, and the excess wax flow was cleaned with a knife.

[0112] Comparative Example 2

[0113] Pure beeswax was used as the pre-filling wax material, containing 100 wt% of beeswax. The pre-filling wax method: the beeswax was placed in a container and heated to 70-80 ℃ to melt; the melted beeswax was placed in a wax injection gun, and the temperature was kept at 60-70 ℃; the wax injection gun was used to fill the small positions of the double-layer wall ceramic core, the wax injection pressure was 0.3-0.4 MPa, and the wax injection speed was 5-8 ml / s; after wax injection, 1-2 min was waited, and the excess wax flow was cleaned with a knife.

[0114] The pre-filling wax materials prepared by the above three examples and two comparative examples were used to fill the multi-layer wall ceramic core, and the pre-filling wax materials and the pre-filling wax process were detected, and the detection results are shown in Table 1.

[0115] Table 1 Detection results of different pre-filling wax materials and pre-filling wax processes

[0116]

[0117] From the above detection results, it can be seen that the pre-filling wax materials prepared in the three examples have small solidification shrinkage, moderate fluidity and high strength, which can effectively reinforce the ceramic core, prevent it from breaking during the transfer and wax pressing process, and the wax pressing mold and the shell can be completely removed after the shell is prepared, without ash residue, avoiding blade inclusion, and solving many problems existing in the prior art.

[0118] The paraffin component, surfactant, modifier, fiber component, whisker component, graphene, bonding wax, biomass component and other raw materials used in the above examples were purchased from Aladdin Reagent Co., Ltd. and Sinoreagent Co., Ltd.

[0119] Particular note: The technical solutions of the present application involve many parameters, and the synergistic effect between each parameter needs to be considered in order to obtain the beneficial effects and significant progress of the present application. Moreover, the value range of each parameter in the technical solution is obtained through a large number of tests. For each parameter and the mutual combination of each parameter, the inventors have recorded a large amount of test data. Due to the limited space, the specific test data is not disclosed here.

[0120] It is not difficult for those skilled in the art to understand that the present application includes any combination of the above-mentioned summary of the present application and the specific embodiments and the parts shown in the drawings. Due to the limited space and in order to make the specification concise, each scheme formed by these combinations has not been described one by one. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low temperature pre-coat wax material for use in complex structured multi-layered wall ceramic cores, characterized in that, The mass percentage of each substance in the low-temperature pre-filling wax material is 46-56wt% of paraffin component, 6-9wt% of surfactant, 6-9wt% of modifier, 6-10wt% of fiber component, 5-8wt% of whisker component, 1-5wt% of graphene, 0.5-1wt% of biomass component, and 12-22wt% of bonding wax, and the sum of the content of each substance is 100wt%. The mass percentage of each substance in the paraffin component is 10-15wt% of 46# semi-refined paraffin, 15-21wt% of 48# fully refined paraffin, 19-25wt% of 52# fully refined paraffin, 19-25wt% of 58# fully refined paraffin, and 22-27wt% of 60# fully refined paraffin. The mass percentage of each substance in the fiber component is 30-43wt% of chopped carbon fiber, 28-40wt% of chopped nylon fiber, and 25-37wt% of chopped aramid fiber; the diameter of the chopped carbon fiber, the chopped nylon fiber, and the chopped aramid fiber is controlled in the range of 5-15μm, and the aspect ratio is controlled in the range of 15-25:

1. The mass percentage of each substance in the whisker component is 25-30wt% of polyamide whisker, 35-40wt% of chitin whisker, and 35-40wt% of cellulose whisker; the diameter of the polyamide whisker, the chitin whisker, and the cellulose whisker is controlled in the range of 0.5-1μm, and the aspect ratio is controlled in the range of 5-15:

1.

2. The low temperature pre-coat wax material for complex multi-layer wall ceramic core according to claim 1, characterized in that, The mass percentage of each substance in the surfactant is 40-53wt% of stearic acid, 25-39wt% of fatty acid, and 13-27wt% of sodium dodecyl benzene sulfonate.

3. The low temperature pre-coat wax material for complex multi-layer wall ceramic core according to claim 2, characterized in that, The mass percentage of each substance in the modifier is 66-80wt% of beeswax and 20-34wt% of polyethylene wax.

4. The low temperature pre-coat wax material for complex multi-layer wall ceramic core according to claim 3, characterized in that, The mass percentage of each substance in the biomass component is 35-50wt% of soybean oil, 25-38wt% of chlorella powder, and 22-35wt% of spirulina powder; the chlorella powder and the spirulina powder each include three grades of particle size, i.e., particle size 18-30μm, particle size 5-18μm, and particle size 0-5μm, and the mass ratio of the particle size 18-30μm, the particle size 5-18μm, and the particle size 0-5μm is 1:1.5-2:2.5-3.

5. A method of prefilling a complex multi-layered wall ceramic core with wax, characterized by, The low-temperature pre-filling wax material for complex structure multi-layer wall ceramic core according to any one of claims 1-4, the pre-filling wax method comprises the following steps in the order: Step one: preparing the low-temperature pre-filling wax material according to the designed process flow and process parameters; Step two: loading the prepared low-temperature pre-filling wax material into a wax injection gun, and controlling the temperature of the low-temperature pre-filling wax material in the wax injection gun to maintain appropriate fluidity, so as to ensure the smooth operation of subsequent wax injection; Step three: according to the designed process parameters, the wax injection gun is used to fill the size small area in the complex structure multilayer wall ceramic core, after the wax injection, standing for a period of time, after the escaped wax flow is preliminary solidified, the escaped excess wax flow is cleaned up by using the cutter, namely the pre-filling wax process of the complex structure multilayer wall ceramic core is completed, and the complex structure multilayer wall ceramic core with pre-filling wax is prepared.

6. The method of prefilling a complex multi-layered wall ceramic core with wax of claim 5, wherein, In step one, the preparation method of the low-temperature pre-filling wax material comprises the following steps in sequence: Step 1.1: according to the designed material ratio, each raw material is weighed and prepared; Step 1.2: all the substances in the fiber component, such as short carbon fiber, short nylon fiber, short aramid fiber and the substances in the whisker component, such as polyamide whisker, chitin whisker and cellulose whisker, are put into a V-type mixer, mixed at room temperature for 20-30 min, the mixing speed is 100-200 r / min, so that each substance is uniformly dispersed, and a fiber-whisker multi-size reinforcing material is obtained and taken out for standby; Step 1.3: all the small Chlorella pyrenoidosa powder and spirulina powder of different sizes are put into a V-type mixer, mixed at room temperature for 10-20 min, the mixing speed is 100-200 r / min, so that each substance is uniformly mixed, and a composite algae powder is obtained and taken out for standby; Step 1.4: all the substances in the surfactant, such as stearic acid, fatty acid and sodium dodecyl benzene sulfonate, are put into a blender, stirred while heating, the stirring speed is 300-400 r / min, after the temperature is heated to 90-110℃, continue to stir for 30-40 min, so that each substance is mutually fused, a surfactant is obtained and taken out for standby; Step 1.5: all the substances in the paraffin component, such as 46# semi-refined paraffin wax, 48# fully refined paraffin wax, 52# fully refined paraffin wax, 58# fully refined paraffin wax and 60# fully refined paraffin wax, are put into a blender, stirred while heating, the stirring speed is 200-300 r / min, after the temperature is heated to 80-95℃, continue to stir for 20-30 min, so that each substance is completely melted; Step 1.6: the stirring temperature and stirring speed are kept unchanged, 80-90 wt% of the surfactant is added into the blender and continues to stir for 1-2 h, so that each substance is mutually fused; Step 1.7: the stirring temperature and stirring speed are kept unchanged, the bonding wax is added into the blender and continues to stir for 20-30 min, so that each substance is mutually fused; Step 1.8: the stirring temperature and stirring speed are kept unchanged, all the substances in the modifier, such as beeswax and polyethylene wax, are added into the blender and continues to stir for 1-2 h, so that each substance is mutually fused; Step 1.9: the stirring temperature and stirring speed are kept unchanged, 10-20 wt% of the surfactant and soybean oil in the biomass component are added into the blender and continues to stir for 1-2 h, so that each substance is mutually fused; Step 1.10: the stirring temperature and stirring speed are kept unchanged, the fiber-whisker multi-size reinforcing material and the composite algae powder are added into the blender and continues to stir for 3-5 h, so that each substance is uniformly mixed; Step 1.11: keep the stirring temperature and stirring speed unchanged, add graphene into the stirring machine and continue stirring for 5-8 h to make the materials mix evenly, thus obtaining the low-temperature pre-filling wax material; Step 1.12: the low-temperature pre-filling wax material is injected into a mold to form a material ingot after cooling and demolding, and the material ingot is sealed and stored for subsequent pre-filling wax process of the ceramic core with complex structure and multi-layer wall.

7. The method of prefilling a complex multi-layered wall ceramic core with wax of claim 6, wherein, In step two, the temperature of the low-temperature pre-filling wax material in the wax injection gun is controlled to be 60-75℃.

8. The method of claim 7, wherein the method further comprises, In step three, the small-size areas in the ceramic core with complex structure and multi-layer wall include double-layer gaps, channel gaps, transverse ribs, cover plates and impact holes; the wax injection pressure is 0.2-0.5 MPa, the wax injection speed is 5-15 ml / s, and the straight-line distance between the gun head of the wax injection gun and the filling position is 5-15 mm; after wax injection, the tool is used to clean the escaped excess wax flow after standing for 1-3 min.

9. The method of claim 8, wherein the method further comprises, For the double-layer gap and channel gap wax injection, the wax injection gun is moved at a uniform speed along the length direction of the gap, and the moving speed is 10-30 mm / s; for the transverse rib and cover plate wax injection, a plurality of wax injection points are selected, the wax injection amount of each wax injection point is 0.5-2 ml / time, and each wax injection point is repeated for several times; for the impact hole wax injection, the gun head of the wax injection gun is aimed at the center of the impact hole and perpendicular to the hole end face for wax injection until the wax material protrudes from the hole end face.

Images