A binder for BJ shaped refractory metal and its preparation method and application

Abstract

The application discloses a kind of BJ forming refractory metal binder and its preparation method and application, belong to binder forming technical field, the binder includes the following weight parts of raw materials: water-based ethylene-acrylic acid copolymer solution 100-150 parts, NaOH solution 80-100 parts, ethanol 150-200 parts, dioctyl phthalate 20-40 parts, yttria powder 10-30 parts, dilute hydrochloric acid 100-130 parts, water 200-300 parts.The application develops a kind of BJ forming refractory metal binder with high viscosity, high bonding strength, high-temperature debinding, not only has good compatibility to a variety of refractory metals, excellent adhesion and stability, with low residue, easy to remove and other advantages, high densification of debinding sintering, excellent mechanical properties, suitable for producing complex, high-performance refractory metal structural parts, has important application in aerospace, national defense industry, nuclear industry, medical field etc..

Description

TECHNICAL FIELD

[0001] The present application relates to the field of binder forming technology, and more particularly to a BJ binder for forming refractory metal and a preparation method and application thereof. BACKGROUND

[0002] With the development of science and technology in the fields of aerospace, defense industry and other cutting-edge industries, the requirements for high-performance refractory metal complex structures are becoming higher and higher in specific environments. Binder jetting meets the use requirements. However, the problem that has not been solved is that the binder needs to have good compatibility with metal powder, and at the same time, it can be completely removed during sintering without leaving any residue. At present, high adhesion, new environmental protection and low carbon residue are the main research directions of binder jetting. In the binder jetting forming process of refractory metal, there is still no binder that meets the use requirements.

[0003] Therefore, how to develop a BJ (binder jetting 3D printing technology) binder for forming refractory metal and a preparation method and application thereof is a technical problem to be solved by those skilled in the art. SUMMARY

[0004] Therefore, the present application provides a BJ binder for forming refractory metal and a preparation method and application thereof.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A BJ binder for forming refractory metal comprises the following raw materials by weight: 100-150 parts of aqueous ethylene-acrylic acid copolymer solution, 80-100 parts of NaOH solution, 150-200 parts of ethanol, 20-40 parts of dioctyl phthalate, 10-30 parts of yttrium oxide powder, 100-130 parts of dilute hydrochloric acid and 200-300 parts of water.

[0007] The present application innovatively develops a BJ binder for forming refractory metal, which has high viscosity, high bonding strength and high-temperature debinding. The binder not only has good compatibility, excellent adhesion and stability for various refractory metals, but also has the advantages of low residue, easy removal, high densification after debinding and sintering, excellent mechanical properties and the like. The binder is suitable for producing complex and high-performance refractory metal structural parts and has important applications in the fields of aerospace, defense industry, nuclear industry, medical treatment and the like.

[0008] Further, the concentration of the NaOH solution is 0.5 mol / L, the concentration of the dilute hydrochloric acid is 4 mol / L, and the particle size of the yttrium oxide powder is 5-20 nanometers.

[0009] The present application further provides a preparation method of the BJ binder for forming refractory metal, comprising the following steps:

[0010] (1) Weigh each raw material according to the above-mentioned BJ binder for refractory metal forming;

[0011] (2) Mix and heat stir the aqueous ethylene-acrylic acid copolymer solution and the NaOH solution, then add ethanol and mix and heat stir, then add dioctyl phthalate and mix and heat stir, and cool to room temperature to obtain a solution, which is ready for use;

[0012] (3) Add yttrium oxide powder to dilute hydrochloric acid and mix and heat stir, cool to room temperature, then add water and mix and stir at room temperature, and then add the solution obtained in step (2) and mix and stir at room temperature to obtain the above-mentioned BJ binder for refractory metal forming.

[0013] The method of the present application uses a variety of viscous substances to modify the BJ binder for refractory metal forming through a multi-stage physical blending process, and generates a BJ binder for refractory metal forming with high viscosity, high bonding strength, and high-temperature debinding capability.

[0014] Further, in step (2), the aqueous ethylene-acrylic acid copolymer solution and the NaOH solution are mixed and heat stirred at 40±5℃ for 60±10min at a stirring speed of 230rpm, then ethanol is added and mixed and heat stirred at 40±5℃ for 30±10min at a stirring speed of 260rpm, and then dioctyl phthalate is added and mixed and heat stirred at 60±5℃ for 30±10min at a stirring speed of 260rpm.

[0015] Further, in step (3), the yttrium oxide powder is added to dilute hydrochloric acid and mixed and heat stirred at 80±5℃ for 10±10min at a stirring speed of 120rpm, then cooled to room temperature, then water is added and mixed and stirred at room temperature for 30±10min at a stirring speed of 200rpm / min, and then the solution obtained in step (2) is added and mixed and stirred at room temperature for 60±10min at a stirring speed of 260rpm / min.

[0016] The present application also provides a use of the above-mentioned BJ binder for refractory metal forming in binder jet forming of refractory metals.

[0017] Further, the refractory metal is tungsten, rhenium or tantalum.

[0018] Further, the use of the above-mentioned BJ binder for refractory metal forming in binder jet forming of refractory metals comprises the following steps:

[0019] 1) The above-mentioned BJ binder for refractory metal forming is used as a binder material, and tungsten powder, rhenium powder or tantalum powder is used as a printing powder material, and a desired model is printed through a binder jet forming process, and the model is cleaned to obtain a printed green body;

[0020] 2) Put the printing green body into the plasma sintering furnace to carry out degreasing, then remove yttrium oxide, and finally high-temperature sintering to obtain pure tungsten parts, pure rhenium parts or pure tantalum parts.

[0021] The beneficial effects of the further technical solutions are as follows: the BJ forming is carried out, and then the degreasing and sintering process is carried out to obtain the final dense and excellent performance structural parts. The binder can realize BJ forming of pure tungsten powder; the structural limit can be ignored, and the hollow, complex and lattice structure that cannot be formed by traditional technology can be formed; the pure tungsten parts prepared by the process have no influence on the purity of tungsten; the carbon content of the pure tungsten parts is less than 0.001%.

[0022] Further, in step 2), the degreasing temperature is 0-800℃, and the degreasing time is 5-6h;

[0023] The yttrium oxide removal temperature is 800-2450℃, and the yttrium oxide removal time is 20-30h;

[0024] The high-temperature sintering temperature of the pure tungsten parts is 2300-3400℃, or the high-temperature sintering temperature of the pure rhenium parts is 2300-3200℃, or the high-temperature sintering temperature of the pure tantalum parts is 2300-3100℃, and the sintering time is 30-50h.

[0025] Further, the particle size of the tungsten powder, rhenium powder or tantalum powder is 5-25μm. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0027] The water-based ethylene-acrylic acid copolymer solution used in the embodiments of the present application is the glue of Shenzhen Xincheng Chemical Co., Ltd., brand: Xinlu, model: XC-3200.

[0028] Embodiment 1

[0029] The preparation method of the binder for BJ forming of refractory metals comprises the following steps:

[0030] (1) Take 100 grams of water-based ethylene-acrylic acid copolymer solution (EAA), 80 grams of 0.5mol / L NaOH solution, 150 grams of ethanol, 20 grams of dioctyl phthalate (DOP), 12 grams of yttrium oxide powder with a particle size of 5-20 nanometers, 100 grams of 4mol / L dilute hydrochloric acid, and 200 grams of pure water;

[0031] (2) The aqueous ethylene-acrylic acid copolymer solution and the NaOH solution are mixed and heated at 40°C for 60 min with stirring at 230 rpm, then ethanol is added and mixed and heated at 40°C for 30 min with stirring at 260 rpm, then dioctyl phthalate is added and mixed and heated at 60°C for 30 min with stirring at 260 rpm, and then cooled to room temperature to obtain a solution, which is ready for use;

[0032] (3) The yttrium oxide powder is added to dilute hydrochloric acid and mixed and heated at 80°C for 10 min with stirring at 120 rpm, then cooled to room temperature, then water is added and mixed and stirred at room temperature for 30 min with stirring at 200 rpm / min, then the solution obtained in step (2) is added and mixed and stirred at room temperature for 60 min with stirring at 260 rpm / min, to obtain a binder for BJ shaped refractory metal.

[0033] A method for preparing a pure tungsten part, comprising the following steps:

[0034] 1) The binder for BJ shaped refractory metal is used as a binder material, and the tungsten powder is used as a printing powder material, and a desired model is printed by a binder jetting forming process, and is cured at 180°C for 2 h, and the model is cleaned to obtain a printed green body;

[0035] 2) The printed green body is placed in a plasma sintering furnace to first perform degreasing, then remove yttrium oxide, and finally high-temperature sintering to obtain a pure tungsten part.

[0036] The temperature curve of step 2) is shown in Table 1:

[0037] Table 1 Temperature curve

[0038]

[0039]

[0040] Comparative Example 1

[0041] First, the tungsten powder is uniformly mixed with the organic binder, and after granulation, it is injected into the mold cavity in a heated and plasticized state (~ 150°C) using an injection molding machine to solidify and form, then the binder in the formed blank is removed by chemical or thermal decomposition, and finally sintered to densify to obtain the final product.

[0042] The viscosity of the binder is measured by a viscometer to be 3.2 cps, and the surface tension is detected by a surface tension instrument to be 16 mN / m.

[0043] The carbon content in the pure tungsten part is measured by infrared spectroscopy;

[0044] Table 2 Carbon content of pure tungsten part of Example 1

[0045] Specimen 1 2 3 4 5 6 Carbon content PPM 0.0006 0.0001 0.0003 0.0002 0.0004 0.0003

[0046] Table 3 Comparative Example 1 Metal Injection Molding Carbon Content

[0047] Specimen 1 2 3 4 5 6 Carbon content PPM 0.16 0.41 0.30 0.42 0.74 0.73

[0048] Table 4 Mechanical Properties After Sintering

[0049] Test item Test method The present invention Metal injection molding Density g / cm 3 ]] Drainage method 19.1 18.9 Tensile strength MPa Electronic universal tensile testing machine 1023 965 Elongation % Electronic universal tensile testing machine 21 23 Dimensional accuracy % Vernier caliper and micrometer ±0.1 ±0.3 Shrinkage % Comparative calculation 16-17 15-25

[0050] Example 2

[0051] A method for preparing a binder for BJ forming refractory metals, comprising the following steps:

[0052] (1) Take 120 grams of aqueous ethylene-acrylic acid copolymer solution, 90 grams of 0.5 mol / L NaOH solution, 170 grams of ethanol, 25 grams of dioctyl phthalate, 15 grams of yttrium oxide powder with a particle size of 5-20 nanometers, 130 grams of dilute hydrochloric acid with a concentration of 4 mol / L, and 220 grams of pure water;

[0053] (2) Mix the aqueous ethylene-acrylic acid copolymer solution and the NaOH solution and heat stir at 40°C for 60 min at a stirring speed of 230 rpm, then add ethanol and mix at 40°C for 30 min at a stirring speed of 260 rpm, then add dioctyl phthalate and mix at 60°C for 30 min at a stirring speed of 260 rpm, and cool to room temperature to obtain a solution for standby;

[0054] (3) Add yttrium oxide powder to dilute hydrochloric acid and mix at 80°C for 10 min at a stirring speed of 120 rpm, cool to room temperature, then add water and mix at room temperature for 30 min at a stirring speed of 200 rpm / min, then add the solution obtained in step (2) and mix at room temperature for 60 min at a stirring speed of 260 rpm / min to obtain a binder for BJ forming refractory metals.

[0055] A method for preparing a pure tungsten part, comprising the following steps:

[0056] 1) Take the binder for BJ forming refractory metals as a binder material, and take tungsten powder as a printing powder material, print a desired model through a binder jetting forming process, solidify at 180°C for 2h, clean the model, and obtain a printing green body;

[0057] 2) Put the printing green body into a plasma sintering furnace, first perform debinding, then remove yttrium oxide, and finally high-temperature sintering to obtain a pure tungsten part.

[0058] The temperature curve of step 2) is the same as that of Example 1.

[0059] The viscosity of the binder was measured by a viscometer to be 4.9 cps, and the surface tension was measured by a surface tension meter to be 25 mN / m.

[0060] The carbon content in the pure tungsten part was measured by infrared spectroscopy;

[0061] Table 5 Carbon content in pure tungsten parts of Example 2

[0062] Specimen 1 2 3 4 5 6 Carbon content PPM 0.0006 0.0007 0.0003 0.0005 0.0007 0.0005

[0063] Table 6 Carbon content in metal injection molding of Comparative Example 1

[0064] Specimen 1 2 3 4 5 6 Carbon content PPM 0.16 0.41 0.30 0.42 0.74 0.73

[0065] Table 7 Mechanical properties after sintering were detected:

[0066] Test item Test method The present invention Metal injection molding Density g / cm 3 ]] Drainage method 19.2 18.9 Tensile strength MPa Electronic universal tensile testing machine 1009 965 Elongation % Electronic universal tensile testing machine 22 23 Dimensional accuracy % Vernier caliper and micrometer ±0.1 ±0.3 Shrinkage % Comparative calculation 16-17 15-25

[0067] Example 3

[0068] A method for preparing a binder for BJ molding of refractory metals, comprising the following steps:

[0069] (1) Take 150 grams of aqueous ethylene-acrylic acid copolymer solution, 100 grams of 0.5 mol / L NaOH solution, 200 grams of ethanol, 40 grams of dioctyl phthalate, 30 grams of yttrium oxide powder with a particle size of 5-20 nanometers, 120 grams of dilute hydrochloric acid with a concentration of 4 mol / L, and 300 grams of pure water;

[0070] (2) Mix the aqueous ethylene-acrylic acid copolymer solution and the NaOH solution, heat and stir at 40°C for 60 min, then add ethanol and mix at 40°C for 30 min, stir at a speed of 260 rpm, then add dioctyl phthalate and mix at 60°C for 30 min, stir at a speed of 260 rpm, cool to room temperature, and obtain a solution, ready for use;

[0071] (3) Add yttrium oxide powder to dilute hydrochloric acid, heat and stir at 80°C for 10 min, stir at a speed of 120 rpm, cool to room temperature, then add water and mix at room temperature for 30 min, stir at a speed of 200 rpm / min, then add the solution obtained in step (2) and mix at room temperature for 60 min, stir at a speed of 260 rpm / min, and obtain a binder for BJ molding of refractory metals.

[0072] A method for preparing a pure tungsten part, comprising the following steps:

[0073] 1) The binder for BJ shaped refractory metal is used as the binder material, and the tungsten powder is used as the printing powder material. The binder jetting molding process is used to print the desired model. The model is cured at 180℃ for 2h, and the model is cleaned to obtain the printed green body.

[0074] 2) The printed green body is placed in a plasma sintering furnace to perform degreasing, then remove yttrium oxide, and finally high-temperature sintering to obtain a pure tungsten part.

[0075] The temperature curve of step 2) is the same as that of example 1.

[0076] The viscosity of the binder is measured by a viscometer to be 6.8cps, and the surface tension is measured by a surface tension meter to be 40mN / m.

[0077] The carbon content in the pure tungsten part is measured by infrared spectroscopy.

[0078] Table 8 Carbon content of the pure tungsten part of example 3

[0079] Specimen 1 2 3 4 5 6 Carbon content PPM 0.0007 0.0002 0.0005 0.0008 0.0004 0.0007

[0080] Table 9 Carbon content of the metal injection molding of comparative example 1

[0081]

[0082]

[0083] Table 10 Mechanical properties after sintering

[0084] Test item Test method The present invention Metal injection molding Density g / cm 3 ]] Drainage method 19.3 18.9 Tensile strength MPa Electronic universal tensile testing machine 1107 965 Elongation % Electronic universal tensile testing machine 20 23 Dimensional accuracy % Vernier caliper and micrometer ±0.15 ±0.3 Shrinkage % Comparative calculation 17-18 15-25

[0085] In the binder formulation range in the present application, the carbon content has no great change and can be basically removed. Only the mechanical properties have certain changes, and the size accuracy and shrinkage rate will be slightly affected, but within a controllable range.

[0086] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A binder for BJ molding of refractory metals, characterized in that, The raw materials include the following weight parts: 100-150 parts of aqueous ethylene-acrylic acid copolymer solution, 80-100 parts of NaOH solution, 150-200 parts of ethanol, 20-40 parts of dioctyl phthalate, 10-30 parts of yttrium oxide powder, 100-130 parts of dilute hydrochloric acid, and 200-300 parts of water; The preparation method of the BJ binder for forming refractory metal comprises the following steps: (1) weighing each raw material according to the BJ binder for forming refractory metal; (2) mixing and heating the aqueous ethylene-acrylic acid copolymer solution and the NaOH solution for stirring, then adding ethanol for mixing and heating for stirring, and then adding dioctyl phthalate for mixing and heating for stirring, and cooling to room temperature to obtain a solution for standby; (3) adding the yttrium oxide powder into the dilute hydrochloric acid for mixing and heating for stirring, cooling to room temperature, then adding water for mixing and stirring at room temperature, and then adding the solution obtained in step (2) for mixing and stirring at room temperature to obtain the BJ binder for forming refractory metal; In step (3), the yttrium oxide powder is added into the dilute hydrochloric acid for mixing and heating for stirring at 80±5℃ for 10±10min, the stirring speed is 120rpm, then cooling to room temperature, adding water for mixing and stirring at room temperature for 30±10min, the stirring speed is 200rpm / min, and then adding the solution obtained in step (2) for mixing and stirring at room temperature for 60±10min, the stirring speed is 260rpm / min.

2. The binder for BJ forming a refractory metal according to claim 1, wherein The concentration of the NaOH solution is 0.5mol / L, the concentration of the dilute hydrochloric acid is 4mol / L, and the particle size of the yttrium oxide powder is 5-20nm.

3. The binder for BJ forming refractory metal of claim 1, wherein In step (2), the aqueous ethylene-acrylic acid copolymer solution and the NaOH solution are mixed for heating and stirring at 40±5℃ for 60±10min, the stirring speed is 230rpm, then adding ethanol for mixing and heating for stirring at 40±5℃ for 30±10min, the stirring speed is 260rpm, and then adding dioctyl phthalate for mixing and heating for stirring at 60±5℃ for 30±10min, the stirring speed is 260rpm.

4. The BJ binder for forming refractory metal according to claim 1 or 2 is applied in the binder jet forming of refractory metal.

5. Use of the binder of claim 4 for the binder jet forming of refractory metals, characterized in that The refractory metal is tungsten, rhenium or tantalum.

6. Use of the binder of claim 5 for the binder jet forming of refractory metals, characterized in that The method comprises the following steps: 1) taking the BJ binder for forming refractory metal as a binder material, taking tungsten powder, rhenium powder or tantalum powder as a printing powder material, printing a required model through a binder jet forming process, cleaning the model to obtain a printed green body; 2) placing the printed green body into a plasma sintering furnace to perform degreasing first, then removing yttrium oxide, and finally high-temperature sintering to obtain a pure tungsten part, a pure rhenium part or a pure tantalum part.

7. Use of the binder of claim 6 for the binder jet forming of refractory metals, characterized in that In step 2), the degreasing temperature is 0-800℃, and the degreasing time is 5-6h; The yttrium oxide removal temperature is 800-2450℃, and the yttrium oxide removal time is 20-30h; The high-temperature sintering temperature of the pure tungsten part is 2300-3400℃, or the high-temperature sintering temperature of the pure rhenium part is 2300-3200℃, or the high-temperature sintering temperature of the pure tantalum part is 2300-3100℃, and the sintering time is 30-50h.

8. Use of the binder of claim 6 for the binder jet forming of refractory metals, characterized in that The particle size of the tungsten powder, the rhenium powder or the tantalum powder is 5-25μm.

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