Near-infrared light induced photo-thermal synergistic curing metal ink and additive manufacturing method

Abstract

The invention relates to the technical field of functional ink, in particular to metal ink based on near-infrared light induced photo-thermal synergistic curing and an additive manufacturing method of the metal ink. The ink is composed of 50%-90% of metal powder, 1%-35% of photosensitive resin, 1%-35% of photosensitive monomer, 0.1%-7% of photoinitiator, 0.1%-5% of upconversion material and 0%-2% of auxiliaries. The curing speed and the curing depth of the ink are improved through the photo-thermal synergistic effect of near-infrared light, the complexity of an ink formula is reduced, and support-free additive manufacturing of the metal ink can be achieved through real-time curing in the printing process. The photo-thermal synergistic curing can be realized without adding a thermal initiator, and meanwhile, the storage stability can be improved, the impurity content in a final product is reduced, and the quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of functional inks, and in particular to a metal ink based on near-infrared light-induced photothermal synergistic curing and an additive manufacturing method thereof. Background Art

[0002] Metal additive manufacturing technology is widely used in the fields of medicine, automobiles, aerospace, etc. At present, metal additive manufacturing technology can be divided into direct metal additive manufacturing and indirect metal additive manufacturing according to the manufacturing process. Direct metal additive manufacturing mainly includes powder bed fusion (PBF) and directed energy deposition (DED). These technologies require high-density energy sources, strict atmosphere control environment and powder size, which leads to high costs and many restrictions on the types and morphology of available metal materials. Indirect metal additive manufacturing methods include metal filled fused deposition (mFFF or mFDM) and binder jetting (BJ). These methods face the problems of limited binder selection and high powder morphology requirements, and it is challenging to achieve highly compatible printing.

[0003] The use of UV-assisted metal ink direct writing additive manufacturing technology has been reported. UV-assisted metal additive manufacturing technology has high requirements for ink viscosity, especially digital light processing (DLP) technology, which requires the metal in the ink to have good dispersion, which brings greater restrictions on resin selection. At the same time, the penetration depth of UV light to metal ink is limited, the curing depth of each layer is limited, and the printing efficiency is low.

[0004] A metal ink provided in the patent document with application number 202211296264.7 adopts a scheme of compounding photoinitiators and thermal initiators, and uses the anti-Stokes effect of upconversion particles to emit ultraviolet light and thermal effect to achieve curing. This scheme uses a thermal initiator. Since thermal initiators require strict temperature storage, some thermal initiators have a low initiation temperature. The ink with high mass ratio will have a higher temperature when prepared in a high-speed disperser, resulting in difficulty in preparation and poor storage stability. In addition, due to its complex composition, there are more impurities after degreasing and sintering. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a metal ink based on near-infrared light-induced photothermal synergistic curing and an additive manufacturing method thereof. The photothermal effect can be simultaneously induced without adding a thermal initiator, promoting the polymerization reaction and forming a cross-linked network, fixing the metal powder particles together, thereby achieving printing of the desired shape.

[0006] The first aspect of the present invention is to provide a metal ink based on near-infrared light-induced photothermal synergistic curing, wherein the metal ink contains raw materials and the mass percentage of each raw material is:

[0007]

[0008]

[0009] Further, the metal powder is selected from one or a combination of iron, gold, copper, aluminum, silver, tin, magnesium, nickel, titanium, vanadium, chromium, manganese, cobalt, zinc, gallium, germanium, aluminum alloy, copper alloy, stainless steel alloy, titanium alloy, nickel alloy, and magnesium alloy;

[0010] Furthermore, the morphology of the metal powder is one or more of spherical, needle-shaped, rod-shaped, flake-shaped, and irregular shapes; and the particle size of the metal powder is 50nm-500μm.

[0011] Furthermore, the photosensitive resin is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, and polyether acrylate;

[0012] Preferably, the aliphatic photosensitive resin contains a long-chain alkyl group or a hydroxyl (carboxyl) group structure. The number of carbon atoms in the long straight-chain or branched alkyl group is 5-18; and the equivalent weight of the hydroxyl (carboxyl) group is 50-2000 mol / g.

[0013] More preferably, the photosensitive resin is one or more of Changxing 6145-100, 61325, 6261, 622-100, 622A-80, Ruiyang RY1202, RY1201, LOHO EPD-171, EPD-172.

[0014] Furthermore, the photosensitive monomer is one or more of an acrylate monomer, an epoxy monomer, and a vinyl ether monomer.

[0015] More preferably, the photosensitive monomer is one or more of dipentaerythritol pentaacrylate, pentaerythritol triacrylate, di-pentaerythritol hexaacrylate, trimethylolpropane triacrylate, 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester, and trivinyl glycol divinyl ether.

[0016] Furthermore, the photoinitiator is a cleavage-type free radical photoinitiator, a hydrogen abstraction-type free radical photoinitiator or a cationic photoinitiator.

[0017] Preferably, the cleavage-type free radical photoinitiator is one or more of benzoin and its derivatives, benzil and its derivatives, acetophenone derivatives, α-hydroxyketone derivatives, α-aminoketone derivatives, acylphosphine oxides, and sulfur-containing photoinitiators;

[0018] The hydrogen abstraction free radical photoinitiator is one or more of benzophenone and its derivatives, thioxanthone and its derivatives, anthraquinone and its derivatives.

[0019] Further preferred are photoinitiators with high activity and long wavelength absorption.

[0020] More preferably, the photoinitiator is one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (I-TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (I-819), and bis(2,6-difluoro-3-(1H-pyrrolyl-1)phenyl)titanium octane (I-784).

[0021] Further, the up-conversion material is one or more of NaYF4, BaYF5, NaGdF4, LiYF4, NaYbF4, Na3ScF6, YF3, and GdOF;

[0022] Furthermore, the auxiliary agent is one or more of a defoaming agent, an anti-settling agent, and a rheological agent.

[0023] The first aspect of the present invention is to provide a method for additive manufacturing of metal ink, comprising the following steps:

[0024] S1. Adding the metal ink into the barrel of a direct writing 3D printer, extruding the metal ink from the nozzle to the printing platform under computer control, and curing and molding under real-time irradiation of a specific light source to obtain an embryo;

[0025] S2. The green body obtained in step S1 is subjected to high temperature degreasing treatment in a specific atmosphere;

[0026] S3. The green body processed in step S2 is subjected to high-temperature and high-pressure sintering in a specific atmosphere and then cooled to room temperature.

[0027] Further, in step S1, the specific light source is a laser light source with a wavelength of 780nm to 2526nm; preferably, the specific light source is a laser light source with a wavelength of 800nm ​​to 1100nm;

[0028] Furthermore, the light source power is required to be 60W / cm 2 More preferably, the power is 90-110W / cm 2 .

[0029] Further, in step S2, the specific atmosphere is one or more mixed gas atmospheres of oxygen, nitrogen, argon, helium, neon, krypton, xenon, and radon;

[0030] Preferably, the specific atmosphere is one or more of oxygen, nitrogen, and argon. More preferably, it is a negative pressure atmosphere.

[0031] Furthermore, the high temperature degreasing treatment temperature is 250°C-600°C.

[0032] Furthermore, in step S3, the temperature of the high temperature and high pressure sintering treatment is 550° C.-1500° C., and the pressure is 0.5 MPa-980 MPa.

[0033] In steps S2 and S3, the heating and cooling rates are 0.1°C to 50°C / min; more preferably, the heating and cooling rates are 0.1°C to 5°C / min.

[0034] In some embodiments of the present invention, a method for preparing a metal ink based on photothermal synergistic curing comprises the following steps (each raw material is expressed in mass percentage):

[0035] (1) 0.1%-7% photoinitiator, 1%-35% photosensitive resin, 1%-35% photosensitive monomer, 0%-2% additive and 0.1%-5% upconversion material are added to a ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2000-5000 r / min to mix uniformly;

[0036] (2) Then, 50% to 95% of the metal powder is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 1000 to 3000 r / min to mix evenly;

[0037] (3) Finally, the ink is filtered to remove mechanical impurities and packaged into sealed containers for storage in the dark.

[0038] The beneficial technical effects of the present invention are at least:

[0039] The present invention utilizes the photothermal synergistic effect of near-infrared light to improve the curing speed and curing depth of the ink, reduce the complexity of the ink formula, and the real-time curing during the printing process can realize the unsupported additive manufacturing of metal ink. After the printed blank is sintered at high temperature and high pressure in a specific atmosphere, a dense metal material can be obtained.

[0040] In the metal ink of the present invention, the upconversion material absorbs long-wavelength near-infrared light and emits short-wavelength ultraviolet light, which causes the photoinitiator to decompose and produce free radical active species, and completes the curing in the shallow layer of the ink; at the same time, the thermal effect of the near-infrared light cooperates with the high thermal conductivity of the metal powder to reach the thermal decomposition temperature of the photoinitiator, so that the photoinitiator in the system quickly decomposes and produces free radical active species, completing the overall curing of the ink. Photothermal synergistic curing can be achieved without adding a thermal initiator, and without adding a thermal initiator, storage stability can be improved, the impurity content in the final product can be reduced, and the quality can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Example 1 Modulus change under variable shear force;

[0042] Figure 2 The morphology and size of different types of metals used in the examples;

[0043] Figure 3 Thermal curing behavior of the metal ink prepared in Example 1 / 2 / 4 under DSC;

[0044] Figure 4 The metal ink prepared in Example 1 has a power of 110 W / cm 2 Real-time temperature during printing;

[0045] Figure 5 The conversion rate of a single line of the metallic ink prepared in Example 1;

[0046] Figure 6 The metal ink prepared in Example 1, the unsupported printing test angles are 60-70-80-90 respectively;

[0047] Figure 7 The metal ink prepared in Example 1 has a large span test span distance of (20-40-60-80-100-120-140 mm) respectively;

[0048] Figure 8 Example 10: Cured thickness and volume under different near-infrared light intensities. DETAILED DESCRIPTION

[0049] In order to further improve the understanding of the preparation process, technical features, etc. involved in the present invention, the present invention is further described below in conjunction with the examples. The preparation process and parameters involved in the examples are only used to illustrate the present invention, and the specific claims of the present invention are not limited thereto. The technicians in this field make some non-essential adjustments and improvements to the present invention based on the above content of the present invention, which still belong to the protection scope of the present invention.

[0050] Embodiment 1:

[0051] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0052] 1% 819, 6% 6145-100, 1% dipentaerythritol hexaacrylate, and 1% NaYF4 are added to a ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the mixture is evenly mixed on a ball mill at a speed of 2650 r / min; then 91% copper powder (spherical, with a particle size of 40 μm) is added to the ball mill, the ball mill is sealed, and the mixture is evenly mixed on a ball mill at a speed of 3000 r / min; finally, the ink is passed through a filter to remove mechanical impurities, and the ink is dispensed into sealed containers for light protection.

[0053] The metal ink is added to the ink tank of the direct writing 3D printer, and the metal ink is extruded from the nozzle to the printing platform under computer control, and solidified under the real-time irradiation of a 980nm laser light source. 2 The green body was obtained by light force of high power; the obtained green body was slowly heated to 650°C at a heating rate of 1°C / min in an air atmosphere for degreasing treatment; the degreased green body was sintered at high temperature and high pressure (1050°C, 0.5MPa) in a hydrogen atmosphere and then slowly cooled to room temperature.

[0054] Embodiment 2:

[0055] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0056] 2% I-784, 25% 6145-100, 5% dipentaerythritol hexaacrylate, and 1% NaYF4 are added to a ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2800 r / min to mix evenly; then 67% cobalt powder (spherical, particle size 500 nm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2600 r / min to mix evenly; finally, the ink is passed through a filter to remove mechanical impurities, and is dispensed into sealed containers for light protection.

[0057] The metal ink is added to the ink tank of the direct writing 3D printer, and the metal ink is extruded from the nozzle to the printing platform under computer control, and solidified under the real-time irradiation of a 980nm laser light source. 2 The embryo was obtained by light force of power; the obtained embryo was slowly heated to 650°C at a heating rate of 1°C / min in a nitrogen atmosphere for degreasing treatment; the degreased embryo was sintered at high temperature and high pressure (950°C, 0MPa) in an atmosphere of 97% argon and 3% hydrogen and then slowly cooled to room temperature.

[0058] Embodiment 3:

[0059] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0060] 5% TPO, 21.5% 61325, 4% pentaerythritol triacrylate, and 2% NaYF4 are added to a ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the mixture is evenly mixed on a ball mill at a speed of 2800 r / min; then 67.5% magnesium powder (flake-shaped, 100 μm in length) is added to the ball mill, the ball mill is sealed, and the mixture is evenly mixed on a ball mill at a speed of 2600 r / min; finally, the ink is passed through a filter to remove mechanical impurities, and the ink is dispensed into sealed containers for light protection.

[0061] Embodiment 4:

[0062] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0063] 1% 784, 1% 819, 12% Changxing 622-100, 4% trimethylolpropane triacrylate, 2% NaYF4 are added to the ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2500r / min to mix evenly. Then 80% stainless steel alloy powder (spherical, particle size μm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 3000r / min to mix evenly. Finally, the ink is passed through a filter to remove mechanical impurities, and is dispensed into a sealed container for light protection.

[0064] Embodiment 5:

[0065] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0066] 2% 784, 8.3% Changxing 6145-100, 1% 1,6-hexanediol diacrylate, and 2% NaYF4 are added to the ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2500r / min to mix evenly. Then 86.7% nickel powder (irregular shape, particle size 20μm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 3000r / min to mix evenly. Finally, the ink is passed through a filter to remove mechanical impurities, and is dispensed into a sealed container for light protection.

[0067] Embodiment 6:

[0068] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0069] 2% 784, 35% EPD-172, 10.7% 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester, 2% NaYbF4 are added to the ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2500r / min to mix evenly. Then 50.3% zinc oxide powder (columnar, particle size 100nm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 3000r / min to mix evenly. Finally, the ink is passed through a filter to remove mechanical impurities, and is dispensed into a sealed container for light protection.

[0070] Embodiment 7:

[0071] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0072] 2% 784, 8% RY1201, 4% trimethylolpropane triacrylate, 5% Na3ScF6 are added to the ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2500r / min to mix evenly. Then 81% silver powder (flaky, particle size 1μm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 3000r / min to mix evenly. Finally, the ink is passed through a filter to remove mechanical impurities, and is dispensed into a sealed container for light protection.

[0073] Embodiment 8:

[0074] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0075] 2% 819, 8% 622-100, 1% trimethylolpropane triacrylate and 3% LiYF4 are added to the ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2500r / min to mix evenly. Then 86% titanium alloy powder (spherical, particle size 10μm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 3000r / min to mix evenly. Finally, the ink is passed through a filter to remove mechanical impurities and is dispensed into a sealed container for light protection.

[0076] Embodiment 9:

[0077] A metal ink based on near-infrared light-induced photothermal synergistic curing, the preparation method of which is as follows: (each raw material is expressed in mass percentage)

[0078] 2% TPO, 15% 622A-80, 4% triethylene glycol divinyl ether, 5% NaGdF4 are added to the ball mill, ceramic balls are added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 2500r / min to mix evenly. Then 74% aluminum alloy powder (flaky, particle size 50μm) is added to the ball mill, the ball mill is sealed, and the ball mill is placed on a ball mill at a speed of 3000r / min to mix evenly. Finally, the ink is passed through a filter to remove mechanical impurities, and is dispensed into a sealed container for light protection.

[0079] Embodiment 10:

[0080] The formula and preparation method of metal ink are the same as those in Example 1. Place the ball mill containing the ink under the near-infrared lamp head, adjust the position of the lamp head so that the page is 100mm away from the lamp head, fix the position of the lamp head, adjust the different light intensities and powers, and use a timer to fix the irradiation time to 3S. After the irradiation is completed, use tweezers to clamp the cured entity and place it in a solvent bottle filled with alcohol. Place it in an ultrasonic cleaner for cleaning. Measure the cleaned entity, use a vernier caliper to measure the thickness of the entity, and use the drainage method to measure the volume of the entity. The cured thickness and volume under different near-infrared light intensities and powers are obtained, and the results are as follows Figure 8 shown.

[0081] Test example:

[0082] (1) Modulus test: The rheological behavior of the ink was studied using a rheometer, with the temperature controlled at 25°C. Steady-state rheological tests were performed with a shear rate range of 0.1-10 2 s -1 The function of viscosity changing with shear rate is obtained. Example 1 Rheological properties of metal ink Figure 1 shown.

[0083] (2) Powder morphology test: The basic morphology and size of the powders were observed by scanning electron microscopy (SEM). Figure 2 shown.

[0084] (3) Thermal curing temperature test of the initiator using differential scanning calorimetry (DSC), Figure 3 The temperature curve of the initiator used in Examples 1, 2, and 4.

[0085] (4) Curing temperature monitoring: A thermal imager was used to detect the real-time temperature of the lines in Example 1 during the curing process.

[0086] like Figure 1 The ink has a significant shear-thinning effect and can be effectively squeezed out of the printer nozzle.

[0087] like Figure 2The ink can use a variety of metal powder types including metal monomers such as cobalt, copper, nickel, and precious metal monomers such as silver; highly active monomers such as magnesium, alloys: alloy stainless steel 304, titanium alloy, aluminum alloy, and metal oxide ceramic ZnO. It can be seen that this printing method is not limited by the powder type. The powder can be spherical, cylindrical, flaky, or irregular.

[0088] like Figure 3 For the three inks with only photoinitiator added, the exothermic peaks under different initiators all occurred within 160°C, which shows that when only photoinitiator is used, the ink can be effectively thermally cured as the heat rises.

[0089] like Figure 4 As shown, the temperature of Example 1 can reach 170°C during the printing process. Figure 3 , indicating that the ink can be cured during the printing process.

[0090] (5) Real-time infrared: A small amount of ink is evenly coated on a KBr salt plate, and the sample is irradiated with a 980 nm laser light source for 375 s. At the same time, a total reflection FT-IR spectrometer is used to continuously scan the exposed sample. The double bond conversion rate is calculated based on the change in the peak area of ​​the acrylic acid double bond at 800-820 cm-1.

[0091] like Figure 5 As shown, the metal ink prepared in Example 1 has a printed line radius of 3.5 mm, and the lines have similar double bond conversion rates at different positions along the radial direction, indicating that the lines are uniformly solidified;

[0092] (6) Printing effect: Observe and judge the smoothness of the printing process and the surface quality of the printed parts.

[0093] Due to the rapid in-situ curing, the ink mentioned in Example 1 is effectively self-supporting and enables large-span and unsupported printing such as Figure 6 , Figure 7 As shown;

[0094] (7) Printing power: Using the ink of Example 1, the cured thickness was measured under different light intensities within the same time. Figure 8 As shown, it shows that with the increase of NIR light intensity power 65W / cm 2 -116W / cm 2 , the curing depth and volume gradually increase. It can be seen that when the light intensity is greater than 65W / cm 2 Afterwards, in-situ deep curing can be achieved under the irradiation of near-infrared light by adding only photoinitiator.

[0095] The present invention is based on the synergistic curing process of the photothermal effect of near-infrared light and the anti-Stokes luminescence of upconversion materials. One part uses upconversion particles doped with lanthanide rare earth elements as a medium. In this process, 980nm long-wave near-infrared light is converted into short-wave ultraviolet light, and the photoinitiator absorbs ultraviolet light and cracks to form free radicals, which promote the polymerization and cross-linking of monomers or resins. Another part uses the thermal effect of near-infrared light. The ink absorbs near-infrared light to undergo photothermal conversion, resulting in thermal cracking of the photoinitiator in the slurry. At the same time, the metal powder exacerbates the thermal effect due to its high thermal conductivity, further promoting the polymerization reaction and forming a cross-linked network, fixing the metal powder particles together, thereby achieving printing of the desired shape. In this process, by controlling the power of the near-infrared light, it is possible to achieve the effect of near-infrared light-induced photothermal synergistic curing without adding a thermal initiator.

[0096] It should be understood that the above detailed embodiments of the present disclosure are only for the purpose of illustrating or explaining the principles of the present disclosure, rather than limiting the present invention. Therefore, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure should be included in the protection scope of the present invention. At the same time, the claims attached to the present invention are intended to cover all changes and modifications of the scope and boundaries of equivalent substitutions that fall within the scope and boundaries of the claims.

Claims

1. A metal ink based on near-infrared light-induced photothermal synergistic curing, characterized in that: The raw materials contained in the metal ink and the mass percentage of each raw material are:

2. The metal ink according to claim 1, characterized in that: The metal powder is selected from one or a combination of iron, gold, copper, aluminum, silver, tin, magnesium, nickel, titanium, vanadium, chromium, manganese, cobalt, zinc, gallium, germanium, aluminum alloy, copper alloy, stainless steel alloy, titanium alloy, nickel alloy, and magnesium alloy; And / or, the morphology of the metal powder is one or more of spherical, needle-shaped, rod-shaped, flake-shaped, and irregular shapes; and the particle size of the metal powder is 50nm-500μm.

3. The metal ink according to claim 1, characterized in that: The photosensitive resin is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, and polyether acrylate; And / or, the photosensitive monomer is one or more of an acrylate monomer, an epoxy monomer, and a vinyl ether monomer.

4. The metal ink according to claim 1, characterized in that: The photoinitiator is a cleavage-type free radical photoinitiator, a hydrogen abstraction-type free radical photoinitiator or a cationic photoinitiator.

5. The metal ink according to claim 1, characterized in that: The up-conversion material is one or more of NaYF4, BaYF5, NaGdF4, LiYF4, NaYbF4, Na3ScF6, YF3, and GdOF; And / or, the auxiliary agent is one or more of a defoaming agent, an anti-settling agent, and a rheological agent.

6. A method for additive manufacturing of metal ink according to claim 1, characterized in that: The steps include: S1. Adding the metal ink into the barrel of a direct writing 3D printer, extruding the metal ink from the nozzle to the printing platform under computer control, and curing and molding under real-time irradiation of a specific light source to obtain an embryo; S2. The green body obtained in step S1 is subjected to high temperature degreasing treatment in a specific atmosphere; S3. The green body treated in step S2 is sintered at high temperature and high pressure in a specific atmosphere and then cooled to room temperature to obtain; In step S1, the light source power is required to be 60W / cm 2 above.

7. The method for additive manufacturing of metal ink according to claim 6, characterized in that: In step S1, the specific light source is a laser light source with a wavelength of 780nm to 2526nm.

8. The method for additive manufacturing using metal ink according to claim 6, characterized in that: In step S1, the specific light source is a laser light source with a wavelength of 800 to 1100 nm; And / or, the light source power is 90-110W / cm 2 .

9. The method for additive manufacturing of metal ink according to claim 6, characterized in that: In step S2, the specific atmosphere is one or more mixed gas atmospheres of oxygen, nitrogen, argon, helium, neon, krypton, xenon, and radon; And / or, the high temperature degreasing treatment temperature is 250°C-600°C.

10. The method for additive manufacturing of metal ink according to claim 6, characterized in that: In step S3, the temperature of the high temperature and high pressure sintering treatment is 550°C-1500°C, and the pressure is 0.5MPa-980MPa.

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