CN115673241B - Soluble ceramic shell or ceramic core material and preparation method and application thereof - Google Patents
Soluble ceramic shell or ceramic core material and preparation method and application thereof Download PDFInfo
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- CN115673241B CN115673241B CN202211319642.9A CN202211319642A CN115673241B CN 115673241 B CN115673241 B CN 115673241B CN 202211319642 A CN202211319642 A CN 202211319642A CN 115673241 B CN115673241 B CN 115673241B
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- 239000000919 ceramic Substances 0.000 title claims abstract description 159
- 239000011162 core material Substances 0.000 title abstract description 106
- 238000002360 preparation method Methods 0.000 title abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 66
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims abstract description 52
- 238000005245 sintering Methods 0.000 claims abstract description 46
- 230000008569 process Effects 0.000 claims abstract description 45
- 238000005266 casting Methods 0.000 claims abstract description 30
- 238000007639 printing Methods 0.000 claims abstract description 30
- 229910000019 calcium carbonate Inorganic materials 0.000 claims abstract description 26
- 238000001035 drying Methods 0.000 claims abstract description 22
- 238000004519 manufacturing process Methods 0.000 claims abstract description 20
- 229910001069 Ti alloy Inorganic materials 0.000 claims abstract description 17
- 239000000292 calcium oxide Substances 0.000 claims abstract description 15
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 15
- 238000010438 heat treatment Methods 0.000 claims abstract description 14
- 238000000465 moulding Methods 0.000 claims abstract description 14
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000006243 chemical reaction Methods 0.000 claims abstract description 5
- 239000000843 powder Substances 0.000 claims description 63
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000007921 spray Substances 0.000 claims description 13
- 239000011230 binding agent Substances 0.000 claims description 9
- 239000000853 adhesive Substances 0.000 claims description 7
- 230000001070 adhesive effect Effects 0.000 claims description 7
- 238000005470 impregnation Methods 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 5
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 claims description 4
- 239000005011 phenolic resin Substances 0.000 claims description 4
- 229920001568 phenolic resin Polymers 0.000 claims description 4
- 229910000838 Al alloy Inorganic materials 0.000 claims description 3
- 229910001018 Cast iron Inorganic materials 0.000 claims description 3
- 229910001208 Crucible steel Inorganic materials 0.000 claims description 3
- 229910000861 Mg alloy Inorganic materials 0.000 claims description 3
- 238000005336 cracking Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 239000011148 porous material Substances 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- 230000002708 enhancing effect Effects 0.000 claims description 2
- 230000000149 penetrating effect Effects 0.000 claims description 2
- 238000013007 heat curing Methods 0.000 claims 1
- 239000011257 shell material Substances 0.000 abstract description 113
- 239000000463 material Substances 0.000 abstract description 10
- 238000001816 cooling Methods 0.000 abstract description 8
- 238000001764 infiltration Methods 0.000 abstract description 7
- 230000008595 infiltration Effects 0.000 abstract description 7
- 238000010521 absorption reaction Methods 0.000 abstract description 5
- 239000010935 stainless steel Substances 0.000 description 21
- 229910001220 stainless steel Inorganic materials 0.000 description 21
- 239000010410 layer Substances 0.000 description 17
- 238000005516 engineering process Methods 0.000 description 14
- 239000006185 dispersion Substances 0.000 description 10
- 239000000243 solution Substances 0.000 description 10
- 239000007788 liquid Substances 0.000 description 8
- 238000012360 testing method Methods 0.000 description 7
- 229910052593 corundum Inorganic materials 0.000 description 6
- 239000010431 corundum Substances 0.000 description 6
- 238000005507 spraying Methods 0.000 description 6
- 239000000654 additive Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 4
- 239000011575 calcium Substances 0.000 description 4
- 238000001723 curing Methods 0.000 description 4
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 4
- 238000010146 3D printing Methods 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 238000005495 investment casting Methods 0.000 description 3
- 238000007873 sieving Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000000016 photochemical curing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000007581 slurry coating method Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
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- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
The invention relates to a soluble ceramic shell or ceramic core, and a preparation method and application thereof, and belongs to the technical field of rapid casting. The method comprises the following steps: (1) Preparing a ceramic shell/core primary blank by adopting a 3DP forming process, and carrying out heating curing, sol infiltration and drying on the ceramic shell/core primary blank to obtain a ceramic shell or ceramic core blank; (2) Placing the ceramic blank into a high-temperature sintering furnace for sintering, and cooling along with the furnace to obtain a soluble ceramic shell or ceramic core; wherein the shell/core material used in the forming process is calcium carbonate. The ceramic shell/core is prepared by the 3DP molding process, has simple process and short production period, is free from support, is suitable for molding the ceramic shell/core with a large complex structure, and can prevent the moisture absorption and the moisture absorption of the material from influencing the shell/core performance in the printing process, the calcium carbonate is decomposed into calcium oxide after high-temperature sintering, the interface reaction with titanium alloy can be avoided during subsequent pouring, and meanwhile, the cast is easier to unshelling due to the solubility of the calcium oxide.
Description
Technical Field
The invention belongs to the technical field of rapid casting, and particularly relates to a soluble ceramic shell or ceramic core and a preparation method and application thereof, in particular to a soluble ceramic shell/core for casting titanium alloy based on 3DP molding and a preparation method thereof.
Background
The titanium alloy has the advantages of small density, high specific strength, long fatigue life, good corrosion resistance, high temperature resistance, good matching with the strength and rigidity of the composite material and the like, and is widely applied to the fields of aerospace, energy chemical industry, medical care and the like. The forging, welding and other modes are difficult to process due to the problems of high chemical activity, low plasticity, low heat conductivity and the like of the titanium alloy, and the investment casting technology well solves the problems, so that the method becomes one of the main methods for preparing titanium alloy structural members at present. The traditional investment casting technology adopts the materials such as wax mould, resin mould and the like to prepare a part model, and then the precision part is obtained through the procedures such as slurry coating, drying, sanding, demoulding, roasting and the like and the casting process. However, in the conventional investment casting technology, the preparation of the ceramic shell/core needs to undergo multiple procedures, so that the production period is long, the production cost is high, the production process is complex, the method has great limitation in forming the large complex ceramic shell/core, and the production needs of the current society are difficult to meet. Therefore, how to simplify the production process, shorten the production period and reduce the preparation cost is an urgent problem to be solved at present.
The additive manufacturing technology refers to the process of slicing a 3D model of a part under the control of a computer, printing the 3D model layer by layer to finally form a complete part, and the technology can be used for directly forming a ceramic shell/core, and obtaining the ceramic shell/core suitable for casting requirements through the processes of drying, degreasing, sintering and the like, so that the production period is greatly shortened, and the production cost is reduced. The existing additive manufacturing technology commonly used for producing the ceramic shell/core comprises a photocuring forming technology, a laser selective sintering technology, a layering extrusion forming technology and the like, but the technologies have more or less problems such as high equipment cost, low surface precision of the ceramic shell/core, support requirement for forming large complex components and the like. Compared with the additive manufacturing technology, the 3DP forming technology does not need laser or auxiliary heating forming, has the advantages of wide material, high forming precision, no support, green environmental protection and the like, has wide application field, and has great potential in preparing the ceramic shell/core.
In the preparation materials of the ceramic shell/core, the materials which are conventionally suitable for preparing the ceramic shell/core for casting the titanium alloy mainly comprise ZrO 2、Y2O3, caO and the like, and the materials can avoid severe interface reaction between the ceramic shell/core and the titanium alloy during casting so as to prevent influencing the casting precision and reducing the casting performance. However, these materials have problems such as high price of ZrO 2 and Y 2O3, greatly increased production cost, and difficult removal of the ceramic shell/core after casting; although the CaO shell/core can be hydrolyzed and unshelling, caO is extremely easy to absorb water in the preparation process, so that the shell/core is cracked, and the use is affected. Therefore, there is a strong need to develop a soluble ceramic shell/core preparation method suitable for titanium alloy casting, which solves the problems existing in the preparation technology and the ceramic shell/core material and meets the industrial production requirements.
Disclosure of Invention
Aiming at the defects or improvement demands of the prior art, the invention provides a soluble ceramic shell or ceramic core based on droplet spray bonding molding, a preparation method and application thereof, wherein CaCO 3 is adopted as a ceramic shell or ceramic core material, the ceramic shell or ceramic core material can be completely decomposed into CaO after being fully sintered, the CaO is directly dissolved by water, the ceramic shell or ceramic core can be dispersed and easily separated from castings, the later shelling process is greatly simplified, the solubility of a dissolved product Ca (OH) 2 is smaller, most of the Ca (OH) 2 can form precipitates, the later recovery treatment is convenient, and meanwhile, compared with the process of directly adopting CaO printing, caCO 3 can avoid the volume change of powder caused by moisture absorption in the printing process and prevent the cracking of the ceramic shell or ceramic core.
According to a first aspect of the present invention there is provided a method of preparing a soluble ceramic shell or core comprising the steps of:
(1) Preparing a ceramic shell or ceramic core primary blank by taking calcium carbonate powder as a raw material and adopting a microdroplet jet bonding molding process, and then performing heating curing, infiltration and drying to obtain a ceramic shell or ceramic core blank;
(2) Sintering the ceramic shell or ceramic core blank obtained in the step (1) to enable calcium carbonate to react to generate calcium oxide, and obtaining the soluble ceramic shell or ceramic core.
Preferably, in the step (2), the sintering is divided into two stages, namely sintering for 1-3 hours at 900-1000 ℃ and then sintering for 2-3 hours at 1300-1500 ℃, wherein the temperature rising rate in the sintering process is 2-5 ℃/min.
Preferably, in the step (1), the temperature of the heating and curing is 190-205 ℃ and the time is 2-4 h.
Preferably, in the step (1), solute molecules in the impregnating solution used for the impregnation are not decomposed at 1500 ℃ or higher; solute components of the impregnating solution cannot react with the structural member in the casting process; the impregnating solution is used for penetrating into pores among calcium carbonate powder, keeping the shape of the ceramic shell or the ceramic core intact, avoiding the collapse of the green body in the sintering process, and enhancing the strength of the sintered green body.
Preferably, in the step (1), the impregnating solution is at least one of nano ZrO 2 dispersion solution or yttrium sol, and the impregnating time is 30 s-3 min.
Preferably, the particle size of the calcium carbonate powder is 325-800 meshes; the adhesive used in the droplet jetting and bonding molding process is phenolic resin; the printing parameters are as follows: the printing layer is 0.05 mm-0.20 mm in height, and the saturation of the adhesive is 70% -140%.
According to another aspect of the present invention, there is provided a soluble ceramic shell or core made by any of the methods.
According to another aspect of the invention there is provided the use of the soluble ceramic shell or ceramic core in a cast structure.
Preferably, the structural member is made of titanium alloy, cast steel, cast iron, aluminum alloy or magnesium alloy.
Preferably, after the casting is completed, the structural member with the ceramic shell or the ceramic core is placed into water, and the ceramic shell or the ceramic core is cracked and dispersed when reacting with water and separated from the structural member, so that the shelling process is completed.
In general, compared with the prior art, the above technical solution conceived by the present invention mainly has the following technical advantages:
(1) The ceramic shell/core is prepared by adopting the droplet spraying bonding molding process, so that the limitation of the traditional process in molding the ceramic shell/core with a large complex structure can be solved, the production period is shortened, the production cost is reduced, and the production requirement of the social market is met. Meanwhile, compared with other additive manufacturing technologies, the micro-droplet jet bonding forming process does not need laser or auxiliary heating forming, and has the advantages of wide materials, high forming precision, no support, green and environment protection and the like, and the application field is wide.
(2) The ceramic shell/core prepared by CaCO 3 can be completely decomposed into CaO after being fully sintered, and the CaO can react with water, so that in the shelling process after pouring, castings with the ceramic shell/core can be fully soaked in hot water, and the ceramic shell/core can be hydrolyzed and collapsed and can be easily separated from the castings; the ceramic shell/core prepared by utilizing materials such as ZrO 2、Y2O3 is often unshelled by applying external force to knock out after casting, which is time-consuming and labor-consuming, so that the later unshelling process can be greatly simplified by adopting CaCO 3 to prepare the ceramic shell/core. The CaO ceramic shell/core dissolution process comprises the following steps:
CaO+H2O＝Ca(OH)2
in the reaction process, a large amount of heat can be released, the solubility of a reaction product Ca (OH) 2 is smaller, the solubility is only 1.65g/L at 20 ℃, and the solubility can be reduced along with the temperature rise, so that most Ca (OH) 2 can form a precipitate, the later recovery treatment is convenient, the pollution is small, the environment is friendly, and the application prospect is wide.
(3) The invention needs to carry out infiltration treatment on the ceramic shell/core before high-temperature sintering, and has the function that infiltration liquid can enter gaps of calcium carbonate powder to improve the strength of the ceramic shell/core; the shape of the ceramic shell/core can be maintained after the binder is completely decomposed, so that collapse is avoided; solute components in the impregnating solution can also avoid interface reaction with titanium alloy in the casting process, so that the casting quality is ensured.
(4) Compared with the method for preparing the ceramic shell/core by directly adopting CaO, the method for preparing the ceramic shell/core by adopting CaCO 3 can avoid the volume change of powder caused by moisture absorption and humidity absorption in the air in the printing process and prevent the ceramic shell/core from cracking. In addition, compared with other ceramic powders such as ZrO 2、Y2O3, caCO 3 has low price, wide source and great development potential.
Based on the preparation characteristics of the soluble ceramic shell/core, the invention researches and designs a preparation method of the soluble ceramic shell/core, which has the advantages of simple preparation procedure, no support in the forming process, low cost and convenient later shelling. The method adopts the droplet spraying bonding forming process to prepare the soluble ceramic shell/core, can solve the limitation of the traditional process in forming the ceramic shell/core with a large complex structure, shortens the production period, reduces the production cost, and has the advantages of wide material, high forming precision, no support, environmental protection and the like, and has wide application field; and the price is low, the sources are wide, and great development potential is provided.
Drawings
FIG. 1 is a schematic flow chart of a method of preparing a soluble ceramic shell/core of the present invention.
Fig. 2 is a graphical representation of a ceramic test sample constructed in accordance with the present invention, wherein a sample was impregnated with a silica sol and b sample was impregnated with a nano ZrO 2 dispersion.
Fig. 3 is a physical diagram of a ceramic sample subjected to collapsibility test.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
As shown in fig. 1, a method for preparing a soluble ceramic shell/core based on droplet spray bonding molding mainly comprises the following steps:
(1) Placing calcium carbonate powder into a powder cylinder, introducing a ceramic shell/core three-dimensional structure model, adjusting printing parameters, and printing out a ceramic shell/core primary blank;
(2) Placing the printed primary blank and the powder bed into a drying box for heating and curing;
(3) Taking out the solidified green body from the powder bed, removing clean powder, performing sol infiltration, and then putting the green body into a drying box for low-temperature drying;
(4) Sintering the ceramic shell/core blank obtained in the step (3) to decompose calcium carbonate to generate calcium oxide, thereby obtaining the soluble ceramic shell/core.
Further, in the step (1), the particle size of the calcium carbonate powder is 325 to 800 mesh.
Further, in the step (4), the sintering is divided into two stages, namely sintering for 1-3 hours at 700-1000 ℃ respectively, then sintering for 2-3 hours at 1300-1500 ℃, and the temperature rising rate in the sintering process is 2-5 ℃/min.
Further, in the step (2), the temperature of the heating and curing is 160-220 ℃ and the time is 2-5 h.
Further, in the step (3), the impregnating liquid used for the impregnation can exist stably at a high temperature; solute components of the impregnating solution cannot react with titanium alloy in the casting process; after the infiltration liquid permeates into pores among the calcium carbonate powders, the effect of keeping the shape of the ceramic shell/core intact and avoiding the collapse of the blank body and the construction of the strength of the ceramic shell/core in the sintering process can be achieved.
Further, the impregnating solution is one or a mixed solution of two of nano ZrO 2 dispersion liquid and yttrium sol, and the impregnating time is 30 s-3 min.
Further, in the step (1), the binder used in the droplet ejection bonding molding process is phenolic resin; the printing parameters are as follows: the printing layer is 0.05 mm-0.20 mm in height, and the saturation of the adhesive is 70% -140%.
Binder saturation (Bs) is one of the important influencing parameters in the droplet ejection printing process, and is defined as the proportional relationship of the single-layer binder volume (V binder) occupying the void volume (V air) in the corresponding powder layer, and its expression:
Wherein ρ Stacking of is the bulk density of the powder; ρ True sense is the true density of the powder; s is the printing area of a single layer; h is the layering thickness.
The invention also provides a soluble ceramic shell/core which is prepared by adopting the preparation method of the soluble ceramic shell/core. The soluble ceramic shell/core is mainly applied to casting of structural members, and can be used for casting of structural members made of cast steel, cast iron, aluminum alloy and magnesium alloy. After casting, the structural member with the ceramic shell/core is put into hot water, and the ceramic shell/core is cracked and dispersed when reacting with water, and is easily separated from the structural member, thus completing the shelling process.
The invention is described in further detail below in connection with several specific embodiments.
Example 1
The preparation method of the soluble ceramic shell/core provided by the embodiment 1 of the invention mainly comprises the following steps:
S1, drying 325-mesh calcium carbonate powder for printing at 80 ℃ for 12 hours, taking out and sieving the powder. And then the screened calcium carbonate powder is fully paved into a powder supply cylinder, a stainless steel plate is placed on the surface of the working cylinder, a layer of ceramic powder is paved, a designed three-dimensional structural model of the ceramic shell/core is imported into a computer, printing parameters are adjusted, a spray head starts to spray phenolic resin binder according to a path of computer slicing, after the spray head finishes one-time ink spraying, the working cylinder descends by one layer thickness, the powder supply cylinder ascends by one layer thickness, the powder paving process is finished through rotation and movement of a powder paving roller, and the powder paving process is sequentially reciprocated, so that the whole ceramic shell/core printing process is finished. Wherein, the printing parameters of the 3D printing equipment are as follows: the print layer was 0.15mm high with 80% adhesive saturation.
S2, after printing is finished, firstly, removing excessive powder on the edge of the stainless steel plate, placing the stainless steel plate in a drying box, heating and solidifying the stainless steel plate at 205 ℃, closing the drying box after solidifying the stainless steel plate for 4 hours, and taking out the stainless steel plate after cooling the stainless steel plate along with a furnace. Next, the powder surrounding the ceramic shell/core green body is removed with a spatula, the green body is removed from the powder bed, and the residual powder on the ceramic shell/core green body is cleaned with a brush. Subsequently, the ceramic shell/core blank is placed in a basin, 40% of nano ZrO 2 dispersion liquid is poured into the basin, timing is started after all parts of the blank are completely impregnated, the impregnated ceramic shell/core blank is taken out and placed in a plate after 3min, and the plate is placed in a drying box at 70 ℃ and is taken out after being dried for 6 h.
S3, sintering the ceramic shell/core blank body in a buried firing mode, uniformly paving 0.2mm plate-shaped corundum powder on a special ceramic plate for sintering, then placing the dried ceramic shell/core blank body on the ceramic plate, completely burying all parts of the blank body by the plate-shaped corundum powder, then placing the blank body into a high-temperature sintering furnace for sintering for 3h at 1000 ℃, sintering for 2h at 1400 ℃, sintering with the technological parameters of 2 ℃/min heating rate, and finally cooling along with the furnace to obtain the soluble ceramic shell/core for titanium alloy casting.
Example 2
The preparation method of the soluble ceramic shell/core provided by the embodiment 2 mainly comprises the following steps:
S1, drying the 500-mesh calcium carbonate powder for printing at 90 ℃ for 10 hours, taking out and sieving the powder. And then the screened calcium carbonate powder is fully paved on a powder supply cylinder, a stainless steel plate is placed on the surface of the working cylinder, a layer of ceramic powder is paved, a designed three-dimensional structural model of the ceramic shell/core is imported into a computer, printing parameters are adjusted, a spray head starts to spray the binder according to a path of computer slicing, after the spray head finishes one-time ink spraying, the working cylinder can drop one layer thickness, the powder supply cylinder rises one layer thickness, the powder paving process is finished through rotation and movement of a powder paving roller, and the whole ceramic shell/core printing process is finished in a reciprocating mode. Wherein, the printing parameters of the 3D printing equipment are as follows: the print layer was 0.12mm high with 100% adhesive saturation.
S2, after printing is finished, firstly, removing excessive powder on the edge of the stainless steel plate, placing the stainless steel plate in a drying box, heating and solidifying the stainless steel plate at 200 ℃, closing the drying box after solidifying the stainless steel plate for 3 hours, and taking out the stainless steel plate after cooling the stainless steel plate along with a furnace. Next, the powder surrounding the ceramic shell/core green body is removed with a spatula, the green body is removed from the powder bed, and the residual powder on the ceramic shell/core green body is cleaned with a brush. Subsequently, the ceramic shell/core blank is placed in a basin, 30% of nano ZrO 2 dispersion liquid is poured into the basin, timing is started after all parts of the blank are completely impregnated, the impregnated ceramic shell/core blank is taken out and placed in a plate after 2min, and the plate is placed in a drying box at 60 ℃ and is taken out after being dried for 5 h.
S3, sintering the ceramic shell/core blank body in a buried firing mode, uniformly paving 0.2mm plate-shaped corundum powder on a special ceramic plate for sintering, then placing the dried ceramic shell/core blank body on the ceramic plate, completely burying all parts of the blank body by the plate-shaped corundum powder, then placing the blank body into a high-temperature sintering furnace for sintering for 2h at 950 ℃, sintering for 2h at 1350 ℃, sintering with technological parameters with a heating rate of 3 ℃/min, and finally cooling along with the furnace to obtain the soluble ceramic shell/core for titanium alloy casting.
Example 3
The preparation method of the soluble ceramic shell/core provided by the embodiment 3 of the invention mainly comprises the following steps:
S1, drying 600-mesh calcium carbonate powder for printing at 100 ℃ for 8 hours, taking out and sieving the powder. And then the screened calcium carbonate powder is fully paved on a powder supply cylinder, a stainless steel plate is placed on the surface of the working cylinder, a layer of ceramic powder is paved, a designed three-dimensional structural model of the ceramic shell/core is imported into a computer, printing parameters are adjusted, a spray head starts to spray the binder according to a path of computer slicing, after the spray head finishes one-time ink spraying, the working cylinder can drop one layer thickness, the powder supply cylinder rises one layer thickness, the powder paving process is finished through rotation and movement of a powder paving roller, and the whole ceramic shell/core printing process is finished in a reciprocating mode. Wherein, the printing parameters of the 3D printing equipment are as follows: the print layer was 0.10mm high with 120% adhesive saturation.
S2, after printing is finished, firstly, removing excessive powder on the edge of the stainless steel plate, placing the stainless steel plate in a drying box, heating and solidifying the stainless steel plate at the temperature of 195 ℃, closing the drying box after solidifying the stainless steel plate for 2 hours, and taking out the stainless steel plate after cooling the stainless steel plate along with a furnace. Next, the powder surrounding the ceramic shell/core green body is removed with a spatula, the green body is removed from the powder bed, and the residual powder on the ceramic shell/core green body is cleaned with a brush. Subsequently, the ceramic shell/core blank is placed in a basin, 15% nano ZrO 2 dispersion liquid is poured into the basin, timing is started after all parts of the blank are completely impregnated, the impregnated ceramic shell/core blank is taken out and placed in a plate after 1.5min, and the plate is placed in a drying box at 50 ℃ and is taken out after being dried for 4 h.
S3, sintering the ceramic shell/core blank body in a buried firing mode, uniformly paving 0.2mm plate-shaped corundum powder on a special ceramic plate for sintering, then placing the dried ceramic shell/core blank body on the ceramic plate, completely burying all parts of the blank body by the plate-shaped corundum powder, then placing the blank body into a high-temperature sintering furnace for sintering for 1h at 900 ℃, sintering for 1.5h at 1300 ℃, sintering with the technological parameters of 3 ℃/min heating rate, and finally cooling along with the furnace to obtain the soluble ceramic shell/core for titanium alloy casting.
Application examples
The impeller is used as an important component in the engine and is widely applied to the fields of automobiles, aerospace and the like at present. Taking an impeller as an example, a soluble impeller shell was produced according to the method in the above-described specific example, the impeller shell was placed in a pressure casting apparatus, molten titanium alloy liquid was poured into a gate above the shell with a crucible, and then pressurized to fill the shell with titanium alloy. And taking out the cast impeller shell after cooling, and putting the impeller shell into hot water for full soaking. And after the ceramic shell material on the surface is completely collapsed, taking the impeller out of the water, cleaning the residual ceramic, wiping off the water, and putting the ceramic shell material into a drying box for drying to obtain the impeller casting.
Infiltration comparative example
A long bar was obtained after sintering using 325 mesh calcium carbonate constructed as in example 1, wherein long bar a was impregnated with silica sol for 3min and long bar b was impregnated with nano ZrO 2 dispersion for 3min. As can be seen from fig. 2, the shape of the long sample a impregnated with the silica sol was changed greatly after sintering, while the shape of the long sample b impregnated with the nano ZrO 2 dispersion remained intact, and no dent deformation occurred. In addition, the long bar-like sample a was broken when taken out from the sintering furnace, and thus it was found that the strength was far inferior to that of the long bar-like sample b impregnated with the nano ZrO 2 dispersion, and thus it was found that the silica sol was not suitable for the impregnation of the calcium carbonate ceramic shell/core green body, and the nano ZrO 2 dispersion could well maintain the shape of the green body, prevent breakage, and was suitable for the impregnation of the calcium carbonate ceramic shell/core green body.
Test examples
(1) Collapsibility test
Two beakers were filled with hot water and each was placed into a ceramic sample for testing. The two samples are prepared by utilizing a droplet spraying bonding molding process, and other molding process parameters are the same except the raw materials, wherein the raw materials of the ceramic sample in the beaker a are 800-mesh alumina, the raw materials of the ceramic sample in the beaker b are 800-mesh calcium carbonate, and the calcium carbonate is completely decomposed into calcium oxide after sintering. After 40min in hot water, the two test samples are shown in FIG. 3. As can be seen from fig. 3, after 40min, the sample in the beaker a does not collapse, and the shape and strength of the sample are not obviously different from those of the sample before being put into hot water; and b, completely collapsing and dissolving the sample in the beaker, and meeting the expected requirement.
(2) Intensity test
The samples of specific examples 1, 2, 3 were tested for flexural strength and the data obtained are given in the following table:
it will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A method for preparing a soluble ceramic shell or core comprising the steps of:
(1) Using calcium carbonate powder as a raw material, adopting a droplet spray bonding molding process to prepare a ceramic shell or ceramic core primary blank, wherein a binder used by the droplet spray bonding molding process is phenolic resin; then heating, solidifying, impregnating and drying to obtain a ceramic shell or ceramic core blank; the impregnating solution is nano ZrO 2 dispersing solution;
(2) Sintering the ceramic shell or ceramic core blank obtained in the step (1) to enable calcium carbonate to react to generate calcium oxide, and obtaining the soluble ceramic shell or ceramic core.
2. The method for preparing a soluble ceramic shell or core according to claim 1, wherein in the step (2), the sintering is divided into two stages, namely, sintering for 1-3 hours at 900-1000 ℃ and then sintering for 2-3 hours at 1300-1500 ℃, wherein the temperature rising rate in the sintering process is 2-5 ℃/min.
3. The method of claim 1, wherein in step (1), the temperature of the heat curing is 190 ℃ to 205 ℃ for 2 hours to 4 hours.
4. The method for producing a soluble ceramic shell or core according to claim 1, wherein in the step (1), solute molecules in the impregnating solution used for the impregnation are not decomposed at 1500 ℃ or below; solute components of the impregnating solution cannot react with the structural member in the casting process; the impregnating solution is used for penetrating into pores among calcium carbonate powder, keeping the shape of the ceramic shell or the ceramic core intact, avoiding the collapse of the green body in the sintering process, and enhancing the strength of the sintered green body.
5. The method of preparing a soluble ceramic shell or core according to claim 4, wherein the impregnation time in step (1) is 30s to 3min.
6. The method for preparing a soluble ceramic shell or core according to claim 1, wherein the particle size of the calcium carbonate powder is 325-800 mesh; the printing parameters are as follows: the printing layer is 0.05 mm-0.20 mm in height, and the saturation of the adhesive is 70% -140%.
7. A soluble ceramic shell or core made by the method of any one of claims 1-6.
8. Use of a soluble ceramic shell or core according to claim 7 in a cast structure.
9. The use according to claim 8, wherein the structural member is made of titanium alloy, cast steel, cast iron, aluminum alloy or magnesium alloy.
10. Use according to claim 8 or 9, wherein after casting, the structural member with the ceramic shell or core is placed in water, the ceramic shell or core being subject to cracking and collapsing upon water reaction, and separated from the structural member, and the shelling process is completed.
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| CN102294436A (en) * | 2011-09-19 | 2011-12-28 | 哈尔滨实钛新材料科技发展有限公司 | Method for precisely casting titanium alloy and titanium aluminum alloy with low cost |
| CN105599106A (en) * | 2015-12-31 | 2016-05-25 | 华中科技大学 | Micro-jetting bonding forming method of ceramic mould core blank |
| CN114180945A (en) * | 2021-12-29 | 2022-03-15 | 华中科技大学 | Additive manufacturing method for ceramic core-type shell integrated piece |
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| US5766329A (en) * | 1996-05-13 | 1998-06-16 | Alliedsignal Inc. | Inert calcia facecoats for investment casting of titanium and titanium-aluminide alloys |
| GB2346340A (en) * | 1999-02-03 | 2000-08-09 | Rolls Royce Plc | A ceramic core, a disposable pattern, a method of making a disposable pattern, a method of making a ceramic shell mould and a method of casting |
| US9308579B2 (en) * | 2012-10-25 | 2016-04-12 | Beihang University | Calcium oxide-based ceramic core and preparation method thereof |
| CN105170907A (en) * | 2015-08-21 | 2015-12-23 | 北京星航机电装备有限公司 | Preparation method for titanium alloy precision casting calcium carbonate shell of polystyrene pattern |
| CN105732007B (en) * | 2016-01-25 | 2019-01-15 | 西安交通大学 | A kind of calcium oxide-based ceramic-mould fast preparation method for complex parts manufacture |
| CN107021771B (en) * | 2017-04-26 | 2021-01-19 | 西安交通大学 | Calcium oxide-based ceramic casting mold manufacturing method based on 3D printing technology |
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| CN102294436A (en) * | 2011-09-19 | 2011-12-28 | 哈尔滨实钛新材料科技发展有限公司 | Method for precisely casting titanium alloy and titanium aluminum alloy with low cost |
| CN105599106A (en) * | 2015-12-31 | 2016-05-25 | 华中科技大学 | Micro-jetting bonding forming method of ceramic mould core blank |
| CN114180945A (en) * | 2021-12-29 | 2022-03-15 | 华中科技大学 | Additive manufacturing method for ceramic core-type shell integrated piece |
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