Mixed reinforcing agent and binder spraying 3D printing method

Abstract

The invention relates to a mixed reinforcing agent which is characterized by comprising a mixture of basic carbonate and one or more of zirconium oxide, zircon powder, white corundum and silicon oxide, and the solute particle size of the mixture is 10 nm to 50 [mu] m. The invention further relates to a binder spraying 3D printing method. According to the scheme, the problem that in the prior art, the strength of a binder jet 3D printing ceramic product is low can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of printing methods, and in particular to a mixed reinforcing agent and binder jetting 3D printing method. Background Art

[0002] Casting cores are key materials in the process of investment casting, which are used to pour molten metal to form castings of a certain shape. Common core materials include core sand, metal, ceramic, etc. Among them, ceramic cores have become the most important core materials used in high melting point metal casting due to their advantages such as high melting point, corrosion resistance, and chemical stability. At present, ceramic cores mainly include silica-based, alumina-based, and calcium oxide-based ceramic cores. At present, the traditional molding methods of ceramic cores mainly include pressing molding, hot die casting, gel injection molding, injection molding, etc. These traditional molding methods cannot form cores with complex shapes, which limits the development of ceramic cores in aerospace and other fields. 3D printing technology provides an innovative technical approach for the molding of complex and special-shaped ceramic cores. 3D printing, also known as additive manufacturing, is a technology that uses digital models to form materials in three-dimensional space by stacking layer by layer.

[0003] 3D printing manufacturing can greatly simplify the manufacturing process and greatly shorten the development cycle. It also has the advantages of high precision, low cost, less material waste, and strong design, and has gradually become one of the most promising key technologies for the future molding of complex and special-shaped ceramic materials. Among the many 3D printing technologies, binder jet 3D printing technology has been widely studied and applied in many fields. However, the current binder jet 3D printed shell / core has the problems of low strength and poor surface quality when casting high-melting-point metals (such as titanium alloys). In addition, the ceramic shell / core for precision casting generally requires not only high strength, but also porosity, both of which have always been difficult to achieve. Summary of the invention

[0004] Based on this, it is necessary to provide a mixed reinforcing agent and a binder jet 3D printing method to address the problem of low strength of binder jet 3D printed ceramic products in the prior art.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention discloses a mixed reinforcing agent, comprising a mixture of basic carbonate and one or more of zirconium oxide, zircon powder, white corundum and silicon oxide, wherein the solute particle size of the mixture is 10 nm-50 μm.

[0007] In one embodiment, the mixture further comprises one or more of an alcohol-based solvent or a water-based solvent, a dispersant, a binder, a defoaming agent, and a penetrant.

[0008] In one embodiment, the basic carbonate includes basic calcium carbonate and basic zirconium carbonate.

[0009] In a second aspect, an embodiment of the present invention discloses a binder jet 3D printing method, which is applied to the mixed reinforcing agent described above, comprising:

[0010] Powder preparation, selecting ceramic powder with a particle size of 10-100 μm, wherein the ceramic powder includes one of aluminum oxide, zirconium oxide, silicon oxide and calcium oxide;

[0011] Pre-sintering treatment, preparing a ceramic green body by using a binder jet 3D printing technology on the ceramic powder, impregnating the mixed reinforcing agent on the surface of the ceramic green body, waiting for 1 to 20 minutes for it to penetrate into the interior of the green body, and then drying it;

[0012] Sintering treatment: after drying, the steel is placed in a sintering furnace for sintering strengthening. The sintering temperature is 1000 to 1800°C and the sintering time is 1 to 10 hours.

[0013] In one embodiment, the drying process includes: first standing still, and then placing in an oven for heating at a temperature of 50 to 200° C. for a time of 1 to 5 hours.

[0014] In one embodiment, when the mixing enhancer includes an alcohol-based solvent, the alcohol-based solvent is burned to achieve drying by ignition.

[0015] In one embodiment, the powder preparation includes: selecting ceramic powder with a particle size of 10-100 μm, the ceramic powder including one of aluminum oxide, zirconium oxide, silicon oxide, and calcium oxide, and mixing the ceramic powder with basic carbonate to form printing powder.

[0016] In one embodiment, the particle size of the basic carbonate is 50 nm to 100 μm.

[0017] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0018] In the mixed reinforcing agent disclosed in the embodiment of the present invention, basic carbonate is added. At this time, during the printing process, the printed part with the mixed reinforcing agent will decompose at high temperature to form submicron oxides such as zirconium oxide and calcium oxide. In previous studies, zirconium oxide, calcium oxide, etc. are usually added to the matrix powder in the form of sintering aids before printing. These oxides are usually added in the form of sintering aids, which may cause uneven mixing, uneven structure after sintering, and low density and strength. However, the zirconium oxide, calcium oxide, etc. formed by the above method have a submicron particle size and can exist in the sintered part in an in-situ generated manner, with a more uniform distribution, which can improve the density, surface quality and mechanical properties of the product. DETAILED DESCRIPTION

[0020] The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0021] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a centered element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a centered element at the same time. The terms "vertical", "horizontal", "left", "right", "top", "bottom", "bottom end", "top end" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0023] The embodiment of the present invention discloses a mixed reinforcing agent, which includes a mixture of basic carbonate and one or more of zirconium oxide, zircon powder, white corundum and silicon oxide, and the solute particle size of the mixture is 10nm-50μm.

[0024] As can be seen from the above, basic carbonate is added to the mixed reinforcing agent disclosed in the embodiment of the present invention. At this time, during the printing process, the printed part with the mixed reinforcing agent added will decompose at high temperature to form submicron oxides such as zirconium oxide and calcium oxide. In previous studies, zirconium oxide, calcium oxide, etc. are usually added to the matrix powder in the form of sintering aids before printing. These oxides are usually added in the form of sintering aids, which may cause uneven mixing, uneven organization after sintering, and low density and strength. However, the zirconium oxide, calcium oxide, etc. formed by the above method have a submicron particle size and can exist in the sintered part in an in-situ generated manner, with a more uniform distribution, which can improve the density, surface quality and mechanical properties of the product.

[0025] In an optional embodiment, the mixture may also include one or more of an alcohol-based solvent or a water-based solvent, a dispersant, a binder, a defoaming agent, and a penetrant to ensure that the formed zirconium oxide, calcium oxide, etc. can be better present in the sintered part in an in-situ generated manner, with a more uniform distribution, thereby further improving the density, surface quality and mechanical properties of the product.

[0026] In an optional embodiment, the basic carbonate may include basic calcium carbonate, basic zirconium carbonate, and of course may also be other carbonates, which is not limited in the embodiment of the present invention.

[0027] Based on the mixed reinforcing agent disclosed in the embodiment of the present invention, the embodiment of the present invention further discloses a binder jetting 3D printing method, which is applied to the mixed reinforcing agent described in any embodiment above. The disclosed binder jetting 3D printing method includes:

[0028] Powder preparation, selecting ceramic powder with a particle size of 10-100 μm, wherein the ceramic powder includes one of aluminum oxide, zirconium oxide, silicon oxide and calcium oxide;

[0029] Pre-sintering treatment, preparing a ceramic green body by using a binder jet 3D printing technology on the ceramic powder, impregnating the mixed reinforcing agent on the surface of the ceramic green body, waiting for 1 to 20 minutes for it to penetrate into the interior of the green body, and then drying it;

[0030] Sintering treatment: after drying, the steel is placed in a sintering furnace for sintering strengthening. The sintering temperature is 1000 to 1800°C and the sintering time is 1 to 10 hours.

[0031] It can be seen from the above that in the binder jet 3D printing method disclosed in the embodiment of the present invention, a mixed reinforcing agent is added during the printing process, so that the mixed reinforcing agent on the printed part will decompose at high temperature to form submicron oxides such as zirconium oxide and calcium oxide. In previous studies, zirconium oxide, calcium oxide, etc. are usually added to the matrix powder in the form of sintering aids before printing. These oxides are usually added in the form of sintering aids, which may cause uneven mixing, uneven organization after sintering, and low density and strength. However, the zirconium oxide, calcium oxide, etc. formed by the above method have a submicron particle size and can exist in the sintered part in an in-situ generated manner, with a more uniform distribution, which can improve the density, surface quality and mechanical properties of the product.

[0032] At the same time, calcium oxide formed by the decomposition of basic calcium carbonate will react with ZrO2 at high temperature to form CaZrO3. CaZrO3 refractory material is a high melting point refractory compound with a melting point of more than 2300℃. CaZrO3 material has the characteristics of small thermal expansion coefficient, high strength, good chemical stability, and strong resistance to alkaline slag erosion. Therefore, for the system with zirconium oxide and basic calcium carbonate, the strength can be significantly improved.

[0033] Furthermore, the carbon dioxide formed by the decomposition of basic carbonates is conducive to the generation of more pores in the ceramic shell. Previous studies often failed to take into account both porosity and mechanical properties. This solution can not only improve the strength, but also make the ceramic shell have a porosity that can meet the casting requirements.

[0034] In an optional embodiment, the drying process may include: first standing still, and then placing in an oven for heating at a temperature of 50 to 200° C. for a time of 1 to 5 hours, so as to ensure the drying effect.

[0035] In an optional embodiment, when the mixed enhancer includes an alcohol-based solvent, the alcohol-based solvent is burned to achieve drying by ignition to ensure a better drying effect.

[0036] In an optional embodiment, the powder preparation may specifically include: selecting a ceramic powder with a particle size of 10-100 μm, wherein the ceramic powder includes one of aluminum oxide, zirconium oxide, silicon oxide, and calcium oxide, and mixing the ceramic powder with basic carbonate to form a printing powder. In this case, basic carbonate is added during the ceramic powder preparation process to ensure better realization of the beneficial effects described above.

[0037] In an optional embodiment, the particle size of the basic carbonate may be 50 nm to 100 μm.

[0038] The following are specific implementation cases:

[0039] Example 1

[0040] (1) Preparation of mixed reinforcing agent: The mixed reinforcing agent mainly includes 50% 10nm basic calcium carbonate + 40% zircon powder + 10% other ingredients. In addition to the above ingredients, it also includes water-based solvents, dispersants, adhesives, defoamers, penetrants and other ingredients.

[0041] (2) Preparation of powder: The powder used for binder jet 3D printing is alumina powder with a median particle size of 10 μm.

[0042] (3) Before sintering: The ceramic product is prepared by binder jet 3D printing technology, and then the mixed reinforcing agent prepared in (1) is impregnated on the surface of the ceramic product, waiting for 10 minutes for it to penetrate into the interior of the green body, and then standing for 24 hours to dry.

[0043] (4) Sintering: After drying, the ceramic product with the mixed reinforcing agent is placed in a sintering furnace for sintering strengthening. The sintering temperature is 1700°C and the sintering time is 2h.

[0044] (5) Performance comparison

[0045]

[0046] Example 2

[0047] (1) Preparation of powder: The powder used for binder jet 3D printing is 80% of 30 μm calcium oxide powder + 10% of 50 nm basic calcium carbonate + 10% of 80 nm basic zirconium carbonate.

[0048] (2) Pre-sintering treatment: The powder in (2) is used to prepare ceramic products through binder jet 3D printing technology.

[0049] (3) Sintering treatment: direct sintering, sintering temperature is 1600℃, sintering time is 3h.

[0050] (4) Performance comparison

[0051]

[0052] Example 3

[0053] (1) Preparation of mixed reinforcing agent: The mixed reinforcing agent mainly includes 60% of 20nm basic zirconium carbonate + 30% of zircon powder + 10% of other ingredients. In addition to the above ingredients, it also includes alcohol-based solvents, dispersants, adhesives, defoamers, penetrants and other ingredients.

[0054] (2) Preparation of powder: The binder used for jet 3D printing powder is 80% 30 μm zirconium oxide powder + 20% 10 μm basic calcium carbonate.

[0055] (3) Before sintering: The ceramic product is prepared by using the binder jet 3D printing technology, and then the mixed reinforcing agent prepared in (1) is impregnated on the surface of the ceramic product, and wait for 1 minute for it to penetrate into the interior of the green body, and then the alcohol-based solvent is burned by ignition to dry the surface.

[0056] (4) Sintering: After drying, the ceramic product with the mixed reinforcing agent is placed in a sintering furnace for post-treatment strengthening. The sintering temperature is 1500°C and the sintering time is 5 hours.

[0057] (5) Performance comparison

[0058]

[0059] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A mixed enhancer, characterized in that: The invention comprises a mixture of basic carbonate and one or more of zirconium oxide, zircon powder, white corundum and silicon oxide, wherein the solute particle size of the mixture is 10 nm-50 μm.

2. The mixing enhancer according to claim 1, characterized in that: The mixture further comprises one or more of an alcohol-based solvent or a water-based solvent, a dispersant, a binder, a defoaming agent, and a penetrant.

3. The mixing enhancer according to claim 1, characterized in that: The basic carbonate includes basic calcium carbonate and basic zirconium carbonate.

4. A binder jet 3D printing method, applied to the hybrid reinforcing agent according to any one of claims 1 to 3, characterized in that: include: Powder preparation, selecting ceramic powder with a particle size of 10-100 μm, wherein the ceramic powder includes one of aluminum oxide, zirconium oxide, silicon oxide and calcium oxide; Pre-sintering treatment, preparing a ceramic green body by using a binder jet 3D printing technology on the ceramic powder, impregnating the mixed reinforcing agent on the surface of the ceramic green body, waiting for 1 to 20 minutes for it to penetrate into the interior of the green body, and then drying it; Sintering treatment: after drying, the steel is placed in a sintering furnace for sintering strengthening. The sintering temperature is 1000 to 1800°C and the sintering time is 1 to 10 hours.

5. The binder jet 3D printing method according to claim 4, characterized in that: The drying process includes: first standing still, and then putting into an oven for heating, the temperature is 50 to 200° C., and the time is 1 to 5 hours.

6. The binder jet 3D printing method according to claim 5, characterized in that: When the mixing enhancer includes an alcohol-based solvent, the alcohol-based solvent is burned to achieve drying by ignition.

7. The binder jet 3D printing method according to claim 4, characterized in that: include: The powder preparation comprises: selecting ceramic powder with a particle size of 10-100 μm, wherein the ceramic powder comprises one of aluminum oxide, zirconium oxide, silicon oxide and calcium oxide, and mixing the ceramic powder with basic carbonate to form printing powder.

8. The binder jet 3D printing method according to claim 7, characterized in that: The particle size of the basic carbonate is 50 nm to 100 μm.

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