Ceramic-based composite powder, preparation method thereof and 3D printing method

Abstract

The invention discloses ceramic-based composite powder, a preparation method thereof and a 3D printing method, belongs to the technical field of ceramic-based composite materials, and aims at solving the problems that in the prior art, ceramic-based composite powder is high in cost, and vanadium-titanium slag is difficult to treat. The ceramic-based composite powder comprises the following components in parts by mass: 50-60 parts of vanadium-titanium slag powder, 20-30 parts of titanium dioxide powder, 10-15 parts of aluminum oxide powder, 5-10 parts of aluminum oxide short fibers, 3-8 parts of a binder and 2-5 parts of a dispersant. The preparation method comprises the step of fully mixing the vanadium-titanium slag powder, the titanium dioxide powder, the aluminum oxide powder, the aluminum oxide short fibers, the binder and the dispersing agent to obtain the ceramic-based composite powder. The method can be used for 3D printing.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic-based composite materials, and in particular relates to a ceramic-based composite powder and a preparation method thereof, and a 3D printing method. Background Art

[0002] Vanadium-titanium slag is the solid waste produced after the smelting of vanadium-titanium magnetite. Its accumulation not only occupies land resources but also poses a risk of environmental pollution. Currently, vanadium-titanium slag is primarily used in metallurgy and building materials, but these applications offer relatively low added value.

[0003] With the rapid development of 3D printing technology, the demand for high-performance, low-cost 3D printing materials is increasing.

[0004] Using vanadium-titanium slag to prepare ceramic-based composite materials for 3D printing can realize the resource utilization of waste and reduce the cost of 3D printing. However, there is currently a lack of mature technology to effectively process vanadium-titanium slag for use in ceramic-based composite materials for 3D printing. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a ceramic-based composite powder and a preparation method thereof, and a 3D printing method, so as to solve the problems of high cost of ceramic-based composite powder and difficult treatment of vanadium-titanium slag in the prior art.

[0006] The purpose of the present invention is mainly achieved through the following technical solutions.

[0007] The present invention provides a ceramic-based composite powder, the composition of which, calculated by mass fraction, includes 50 to 60 parts of vanadium-titanium slag powder, 20 to 30 parts of titanium dioxide powder, 10 to 15 parts of aluminum oxide powder, 5 to 10 parts of aluminum oxide short fibers, 3 to 8 parts of a binder, and 2 to 5 parts of a dispersant.

[0008] Furthermore, the binder is sodium carboxymethyl cellulose.

[0009] Furthermore, the dispersant is sodium polyacrylate.

[0010] The present invention also provides a method for preparing a ceramic-based composite powder, which is used for preparing the above-mentioned ceramic-based composite powder;

[0011] The preparation method comprises the following steps:

[0012] Step 1: Weigh vanadium-titanium slag powder, titanium dioxide powder, alumina powder, alumina short fibers, a binder, and a dispersant according to the ratio;

[0013] Step 2: Fully mix the vanadium-titanium slag powder, titanium dioxide powder, alumina powder, alumina short fibers, a binder and a dispersant to obtain a ceramic-based composite powder.

[0014] Furthermore, before step 1, the following steps are also included:

[0015] Soaking alumina short fibers in silane coupling agent ethanol solution;

[0016] Take out the alumina short fibers and dry them.

[0017] Furthermore, the mass fraction of the silane coupling agent ethanol solution is 5% to 10%, the soaking time is 2h to 3h, and the drying temperature is 80°C to 85°C.

[0018] The present invention also provides a 3D printing method, comprising the following steps:

[0019] Step a: adding deionized water to the ceramic-based composite powder and ball milling to obtain a ceramic-based slurry, wherein the ceramic-based composite powder is obtained by the above-mentioned preparation method;

[0020] Step b: injecting the ceramic-based slurry into the barrel of the 3D printer, and printing and molding according to a preset three-dimensional model through an extrusion molding process to obtain a 3D printing blank.

[0021] Furthermore, in step a, the ball milling speed is 300 r / min to 400 r / min, and the ball milling time is 4 h to 6 h.

[0022] Furthermore, in step a, the solid content of the ceramic-based slurry is 60% to 70%.

[0023] Furthermore, in step b, the printing temperature is 180° C. to 200° C., and the printing pressure is 0.5 MPa to 1.0 MPa.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] A) The ceramic-based composite powder provided by the present invention is suitable for 3D printing manufacturing in the fields of aerospace parts, high-temperature resistant molds, etc. On the one hand, using vanadium-titanium slag, a solid waste, as the main raw material, low-cost vanadium-titanium slag is used to replace some high-priced ceramic raw materials, realizing its high-value utilization in the field of high-performance ceramic-based composite powders, reducing accumulation pollution, improving resource utilization, significantly reducing the production cost of ceramic-based composite powders, and improving the market competitiveness of 3D printed products.

[0026] B) The ceramic-based composite powder provided by the present invention has excellent performance by adding alumina short fiber reinforcement and a reasonable raw material ratio. At the same time, the good slurry fluidity can also ensure the printing molding accuracy and surface quality.

[0027] C) The ceramic-based composite powder provided by the present invention comprises titanium dioxide, aluminum oxide and vanadium-titanium slag together forming a ceramic matrix, aluminum oxide short fibers are used to enhance the mechanical properties of the ceramic-based composite powder, and a binder and a dispersant are used to ensure the formability and uniformity of the ceramic-based composite powder.

[0028] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages will become apparent from the description or be understood through practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the embodiments of the description and the contents particularly pointed out in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0030] Figure 1 A flow chart of the method for preparing the ceramic-based composite powder provided by the present invention;

[0031] Figure 2 This is a flow chart of the demolding process for preparing vanadium-titanium slag powder in the method for preparing ceramic-based composite powder provided by the present invention. It should be noted that the components in the left and right figures are the same, only the positional relationship has changed. Therefore, the right figure is not numbered;

[0032] Figure 3 This is a flow chart of the 3D printing method provided by the present invention.

[0033] Reference numerals:

[0034] 1-External mold; 2-Heat exchange straight tube; 3-Heat exchange baffle; 4-Discharging push plate; 5-Rotation drive motor; 6-Rotation magnetic sleeve; 7-Rotation magnetic ring. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0036] In the first aspect of the present invention, a ceramic-based composite powder is provided, which can be used for 3D printing. The composition thereof, calculated by mass fraction, includes 50 to 60 parts of vanadium-titanium slag powder, 20 to 30 parts of titanium dioxide powder, 10 to 15 parts of alumina powder, 5 to 10 parts of alumina short fibers, 3 to 8 parts of a binder and 2 to 5 parts of a dispersant.

[0037] Compared with the existing technology, the ceramic-based composite powder provided by the present invention is suitable for 3D printing manufacturing in the fields of aerospace parts, high-temperature resistant molds, etc. On the one hand, it uses vanadium-titanium slag, a solid waste, as the main raw material, and uses low-cost vanadium-titanium slag to replace part of the high-priced ceramic raw materials, thereby realizing its high-value utilization in the field of high-performance ceramic-based composite powders, reducing accumulation pollution, improving resource utilization, significantly reducing the production cost of ceramic-based composite powders, and improving the market competitiveness of 3D printed products.

[0038] On the other hand, by adding alumina short fiber reinforcement and a reasonable raw material ratio, the prepared ceramic-based composite powder has excellent performance. After testing, the compressive strength of 3D printed products made with ceramic-based composite powder can reach 120MPa~150MPa, the flexural strength reaches 20MPa~30MPa, and the fracture toughness is 5MPa·m1 / 2~8MPa·m1 / 2. At the same time, good slurry fluidity can also ensure printing molding accuracy and surface quality.

[0039] Specifically, titanium dioxide and alumina together with vanadium-titanium slag constitute the ceramic matrix, alumina short fibers are used to enhance the mechanical properties of the ceramic-based composite powder, and binders and dispersants are used to ensure the formability and uniformity of the ceramic-based composite powder.

[0040] Illustratively, the binder is sodium carboxymethyl cellulose and the dispersant is sodium polyacrylate.

[0041] The second aspect of the present invention further provides a method for preparing a ceramic-based composite powder, which is used to prepare the ceramic-based composite powder provided in the first aspect.

[0042] The preparation method, see Figure 1 , including the following steps:

[0043] Step 1: Weigh vanadium-titanium slag powder, titanium dioxide powder, alumina powder, alumina short fibers, a binder, and a dispersant according to the ratio;

[0044] Step 2: Fully mix the vanadium-titanium slag powder, titanium dioxide powder, alumina powder, alumina short fibers, a binder and a dispersant to obtain a ceramic-based composite powder.

[0045] Compared with the prior art, the beneficial effects of the method for preparing the ceramic-based composite powder provided by the present invention are substantially the same as the beneficial effects of the ceramic-based composite powder provided by the first aspect, and are not described in detail here.

[0046] In order to improve the activity and specific surface area of ​​the vanadium-titanium slag powder and reduce the content of ferromagnetic impurities in the vanadium-titanium slag powder, the following steps are further included before step 1:

[0047] Magnetic separation is performed on the vanadium-titanium slag powder to remove ferromagnetic impurities in the vanadium-titanium slag powder;

[0048] The magnetically separated vanadium-titanium slag powder is calcined at a temperature of 1000° C. to 1100° C. for 3 to 4 hours, so that the crystal structure of the vanadium-titanium slag powder is fully transformed;

[0049] The calcined vanadium-titanium slag powder is ultrafinely ground using a jet mill to refine the particle size of the vanadium-titanium slag powder to 1 μm to 3 μm, thereby increasing the activity and specific surface area of ​​the vanadium-titanium slag powder.

[0050] In order to enhance the interfacial bonding between the alumina short fibers and the matrix, the following steps are further included before step 1:

[0051] Soaking the alumina short fibers in a silane coupling agent ethanol solution with a mass fraction of 5% to 10% for 2 to 3 hours;

[0052] Take out the alumina short fibers and dry them at 80°C to 85°C.

[0053] In a third aspect, the present invention further provides a method for preparing a ceramic-based composite powder, which is substantially the same as the method for preparing a ceramic-based composite powder provided in the second aspect, except that:

[0054] The preparation method of the above-mentioned vanadium-titanium slag powder comprises the following steps:

[0055] Directly guide the liquid vanadium-titanium slag discharged from the blast furnace into the slag casting mold;

[0056] The vanadium-titanium slag in the slag casting mold is sequentially air-cooled for 3 to 5 minutes and spray-cooled for 30 to 60 minutes to obtain a solid slag block. For example, the cooling rate of the air cooling is 5°C / s to 10°C / s, and the cooling rate of the spray cooling is 30°C / s to 60°C / s. During the air cooling process, a slag shell is formed on the surface of the liquid vanadium-titanium slag in the slag casting mold, and the interior of the vanadium-titanium slag in the slag casting mold is still liquid blast furnace slag. During the spraying process, the liquid blast furnace slag inside the vanadium-titanium slag in the slag casting mold is completely solidified.

[0057] The solid slag blocks are crushed and classified to obtain dense, high-strength vanadium-titanium slag powder with different particle size ranges.

[0058] In this way, by adopting the method of air cooling combined with spray cooling, a dense and high-strength vanadium-titanium slag powder can be obtained. Specifically, air cooling is a slow cooling method, which can promote crystallization on the surface of the vanadium-titanium slag in the slag casting mold to form a slag shell, thereby avoiding thermal stress from causing the slag shell to rupture. This slag shell can serve as an isolation layer to prevent subsequent spray cooling water from directly contacting the liquid vanadium-titanium slag in the slag casting mold to produce water-quenched slag (lower strength and more pores), thereby ensuring the density and high strength of the obtained vanadium-titanium slag powder; spray cooling is a fast cooling method. Through spray cooling, effective heat transfer can be achieved between the spray cooling water and the liquid vanadium-titanium slag under the slag shell through the slag shell. With the slag shell as the base layer, a crystallization layer is formed layer by layer downward to ensure the crystallization uniformity of the solid slag block formed, thereby ensuring the density and high strength of the obtained vanadium-titanium slag powder.

[0059] Specifically, the preparation method of the above-mentioned vanadium-titanium slag powder comprises the following steps:

[0060] Step A: The liquid blast furnace slag discharged from the blast furnace slag outlet is directed into the slag casting mold through the guide groove 2;

[0061] Step B: driving the slag casting mold to slide along the slide rail so that the slag casting mold is located below the air cooling assembly, and the slag casting mold stops sliding;

[0062] The air cooling component is turned on to spray cooling air onto the surface of the liquid vanadium-titanium slag in the slag casting mold, so that a slag shell is formed on the surface of the liquid vanadium-titanium slag in the slag casting mold;

[0063] Step C: the slag casting mold slides along the slide rail so that the slag casting mold is located below the spray cooling assembly, and the slag casting mold stops sliding;

[0064] The spray cooling assembly is turned on, and spray water is sprayed on the surface of the slag shell. Heat is transferred between the slag shell and the liquid blast furnace slag inside the vanadium-titanium slag in the slag casting mold to obtain a solid slag block.

[0065] Step D: crushing the solid slag blocks to obtain dense, high-strength vanadium-titanium slag powder.

[0066] For the structure of the slag mold, see Figure 2, which includes an outer mold 1, a heat exchange straight tube 2 and a heat exchange baffle 3. The heat exchange straight tube 2 is arranged in the outer mold and is axially perpendicular to the bottom wall of the outer mold. For example, the axial direction of the heat exchange straight tube 2 is arranged in the vertical direction, the top of the heat exchange straight tube 2 is closed, and the bottom is open. The heat exchange baffle 3 is arranged in the heat exchange straight tube 2 and is arranged along the axial direction of the heat exchange straight tube 2. There is a gap between the top of the heat exchange baffle 3 and the top of the heat exchange straight tube 2, dividing the heat exchange straight tube into a liquid inlet rectangular tube, a top connecting tube and a liquid outlet rectangular tube connected in sequence. In this way, while the spraying cold water transfers heat from the top of the outer mold 1 through the slag shell and the liquid blast furnace slag inside the vanadium-titanium slag in the outer mold 1, the heat exchange straight tube 2 can be cooled from the inside of the liquid blast furnace, thereby improving the cooling uniformity and cooling speed.

[0067] In order to facilitate the demolding of the solid slag block, the heat exchange straight tube 2 can be used to achieve rapid demolding of the solid slag block. Specifically, the inner cavity shape of the outer mold 1 is a cube, the outer wall of the heat exchange straight tube 2 is a threaded structure, and the outer wall of the threaded structure is cylindrical. The above-mentioned slag casting mold also includes a unloading push plate 4 and a unloading reciprocating motor, and the output end of the unloading reciprocating motor is connected to the unloading push plate 4.

[0068] When demolding and unloading are required, the heat exchange straight tube 2 is rotated. Due to the existence of the threaded structure and the internal limit of the cubic inner cavity of the outer mold 1, the solid slag block can only move upward, thereby detaching from the inner cavity of the casting slag mold and realizing demolding. Then, the unloading reciprocating motor is turned on, and the unloading reciprocating motor drives the unloading push plate 4 to push the solid slag block away from the top of the outer mold 1, so that the solid slag block falls into the crushing assembly for crushing.

[0069] It can be understood that in order to drive the rotation of the heat exchange straight tube 2, the above-mentioned slag casting mold also includes a rotary drive motor 5. When the outer mold 1 moves to the top of the rotary drive motor 5, the output shaft of the rotary drive motor 5 is fixedly connected to the bottom of the heat exchange straight tube 2, and the rotary drive motor 5 is used to drive the heat exchange straight tube 2 to rotate, thereby realizing the demolding of the solid slag block.

[0070] In order to realize the connection between the rotary drive motor 5 and the heat exchange straight pipe 2, the above-mentioned resource processing equipment also includes a rotary magnetic sleeve 6 and a rotary magnetic ring 7. The magnetic sleeve is sleeved on the outer wall of the output shaft of the rotary drive motor 5 and is slidably connected to the output shaft. The cross-sectional shape of the inner wall of the magnetic sleeve and the cross-sectional shape of the output shaft of the rotary drive motor 5 are both rectangular.

[0071] In this way, when the outer mold 1 runs to the bottom of the unloading push plate 4, the position of the heat exchange straight tube 2 corresponds to the output shaft of the rotating drive motor 5, and the rotating magnetic sleeve 6 is energized and magnetically attracted to the rotating magnetic ring 7, so that the rotating magnetic sleeve 6 moves toward the direction of the heat exchange straight tube 2 and is sleeved on the bottom of the heat exchange straight tube 2, thereby realizing a fixed connection between the heat exchange straight tube 2 and the output shaft of the rotating drive motor 5.

[0072] In a fourth aspect, the present invention provides a 3D printing method, see Figure 3 , including the following steps:

[0073] Step a: adding deionized water to the ceramic-based composite powder, and using a planetary ball mill at a speed of 300 rpm to 400 rpm for 4 to 6 hours to prepare a ceramic-based slurry with good fluidity and stability, wherein the solid content of the ceramic-based slurry is 60% to 70%;

[0074] Step b: injecting the ceramic-based slurry into the barrel of the 3D printer, and printing and molding according to the preset three-dimensional model through the extrusion molding process. The printing temperature is 180°C to 200°C, and the printing pressure is 0.5MPa to 1.0MPa to obtain a 3D printed blank.

[0075] In order to further improve the mechanical properties of the 3D printed blank, the above step b is followed by the following steps:

[0076] Dry the 3D printed blank at 80℃~85℃ for 12h~15h to remove most of the moisture;

[0077] The dried 3D printing blank is placed in a high-temperature sintering furnace, heated to 1400°C to 1500°C at a heating rate of 5°C / min to 8°C / min, and kept warm for 2h to 3h to obtain a 3D printed product.

[0078] Example 1

[0079] Pretreatment of vanadium-titanium slag: The vanadium-titanium slag after magnetic separation and iron removal is calcined in a high-temperature furnace at 1000°C for 3 hours, and then ground to a particle size of 1-3 μm by a jet mill to obtain pretreated vanadium-titanium slag powder.

[0080] Reinforcement pretreatment: soak the alumina short fibers in 5% silane coupling agent ethanol solution for 2 hours and dry them at 80°C.

[0081] Mixing ratio of raw materials: take 50 parts of pretreated vanadium titanium slag powder, 30 parts of titanium dioxide powder, 15 parts of alumina powder, 5 parts of pretreated alumina short fibers, 8 parts of sodium carboxymethyl cellulose and 2 parts of sodium polyacrylate according to the mass ratio, and mix them thoroughly.

[0082] Slurry preparation: add deionized water, control the solid content to 60%, and ball mill at a speed of 300 r / min for 6 hours to prepare slurry.

[0083] Material molding: The slurry is injected into the 3D printer and extruded and printed at 180°C and 0.5MPa.

[0084] Post-processing: The printed body was dried at 80°C for 12 h, heated to 1400°C at a rate of 5°C / min, and sintered for 3 h.

[0085] Example 2

[0086] Pretreatment of vanadium-titanium slag: calcined the vanadium-titanium slag at 1050°C for 3.5h and ground into 1-3μm.

[0087] Reinforcement pretreatment: same as in Example 1.

[0088] Raw material mixing ratio: according to the mass ratio, take 55 parts of pretreated vanadium titanium slag powder, 25 parts of titanium dioxide powder, 12 parts of aluminum oxide powder, 8 parts of pretreated aluminum oxide short fibers, 5 parts of sodium carboxymethyl cellulose and 3 parts of sodium polyacrylate and mix them.

[0089] Slurry preparation: solid content 65%, ball milling at 400 r / min for 4 h.

[0090] Material molding: 190℃, 0.7MPa printing.

[0091] Post-processing: After drying, heat to 1450℃ and keep warm for 2.5h before sintering.

[0092] Example 3

[0093] Pretreatment of vanadium-titanium slag: calcination at 1100℃ for 4h, grinding to 1-3μm.

[0094] Reinforcement pretreatment: same as in Example 1.

[0095] Raw material mixing ratio: according to the mass ratio, take 60 parts of pretreated vanadium titanium slag powder, 20 parts of titanium dioxide powder, 10 parts of aluminum oxide powder, 10 parts of pretreated aluminum oxide short fibers, 3 parts of sodium carboxymethyl cellulose and 5 parts of sodium polyacrylate and mix them.

[0096] Slurry preparation: solid content 70%, ball milling at 350 r / min for 5 h.

[0097] Material molding: 200℃, 1.0MPa printing.

[0098] Post-processing: After drying, sinter at 1500℃ for 2h.

[0099] The 3D printed products prepared in the above three embodiments were subjected to performance tests, and the test results are shown in Table 1.

[0100] Table 1 Performance parameters of 3D printed products of Examples 1 to 3

[0101]

[0102] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A ceramic-based composite powder, characterized in that: The composition is calculated by mass fraction and includes 50 to 60 parts of vanadium-titanium slag powder, 20 to 30 parts of titanium dioxide powder, 10 to 15 parts of aluminum oxide powder, 5 to 10 parts of aluminum oxide short fibers, 3 to 8 parts of binder and 2 to 5 parts of dispersant.

2. The ceramic-based composite powder according to claim 1, characterized in that The binder is sodium carboxymethyl cellulose.

3. The ceramic-based composite powder according to claim 1, characterized in that The dispersant is sodium polyacrylate.

4. A method for preparing a ceramic-based composite powder, characterized in that: Used for preparing the ceramic-based composite powder according to any one of claims 1 to 3; The preparation method comprises the following steps: Step 1: Weigh vanadium-titanium slag powder, titanium dioxide powder, alumina powder, alumina short fibers, a binder, and a dispersant according to the ratio; Step 2: Fully mix the vanadium-titanium slag powder, titanium dioxide powder, alumina powder, alumina short fibers, a binder and a dispersant to obtain a ceramic-based composite powder.

5. The method for preparing ceramic-based composite powder according to claim 4, characterized in that: The following steps are also included before step 1: Soaking alumina short fibers in silane coupling agent ethanol solution; Take out the alumina short fibers and dry them.

6. The method for preparing ceramic-based composite powder according to claim 5, characterized in that: The mass fraction of the silane coupling agent ethanol solution is 5% to 10%, the soaking time is 2h to 3h, and the drying temperature is 80°C to 85°C.

7. A 3D printing method, characterized in that: The steps include: Step a: adding deionized water to a ceramic-based composite powder and ball-milling to obtain a ceramic-based slurry, wherein the ceramic-based composite powder is obtained by the preparation method according to any one of claims 4 to 6; Step b: injecting the ceramic-based slurry into the barrel of the 3D printer, and printing and molding according to a preset three-dimensional model through an extrusion molding process to obtain a 3D printing blank.

8. The 3D printing method according to claim 7, characterized in that: In the step a, the ball milling speed is 300 rpm to 400 rpm, and the ball milling time is 4 h to 6 h.

9. The 3D printing method according to claim 7, wherein: In the step a, the solid content of the ceramic-based slurry is 60% to 70%.

10. The 3D printing method according to claim 7, wherein: In the step b, the printing temperature is 180° C. to 200° C., and the printing pressure is 0.5 MPa to 1.0 MPa.

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