Micro spherical titanium or titanium alloy powder and preparation method and application thereof

Abstract

The invention belongs to the technical field of powder preparation, and particularly relates to fine spherical titanium or titanium alloy powder and a preparation method and application thereof. The preparation method provided by the invention comprises the following steps: (1) carrying out vacuum-pumping treatment on atomization powder preparation equipment, and then filling inert gas into the atomization powder preparation equipment; (2) the two raw material wires are connected with the positive electrode and the negative electrode of an arc power source respectively and then enter a guide pipe through a wire feeding device, a raw material wire contact point is formed at the outlet end of the guide pipe, and arc molten liquid drops are generated; the raw material wire is a titanium or titanium alloy wire; and (3) atomizing the electric arc molten liquid drops obtained in the step (2) through at least two paths of atomizing airflow to obtain the fine spherical titanium or titanium alloy powder, wherein airflow of the air inlet valve intersects to form an airflow focus which is concentrated at the same point with the raw material wire contact point in the step 2); and 4) screening the atomized powder obtained in the step 3). According to the method, the atomization efficiency can be improved, the yield of the titanium or titanium alloy powder is increased, and the cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of powder preparation, and in particular relates to a micro-spherical titanium or titanium alloy powder and a preparation method and application thereof. Background Art

[0002] Titanium has the characteristics of high specific strength, good corrosion resistance, and good biocompatibility. It is widely used in the fields of aerospace and biomedicine. Additive manufacturing technology is a processing technology that slices the three-dimensional model of the part to be formed into two-dimensional sections layer by layer, and then stacks the material layer by layer along the height direction to finally form a solid body. Compared with traditional metal processing technology, the use of additive manufacturing technology to prepare titanium or titanium alloy parts has unique advantages in complex shape realization, product customization and material utilization. Therefore, additive manufacturing technology is widely used in the preparation of titanium or titanium alloy products.

[0003] Titanium or titanium alloy powder is the key raw material for the preparation of titanium or titanium alloy products by additive manufacturing technology. It is required to have the characteristics of fine particle size, high sphericity, and low oxygen content. At present, the technologies that can industrially produce high-quality spherical titanium or titanium alloy powder mainly include plasma rotating electrode method, inert gas atomization method, plasma torch atomization method, etc. The plasma rotating electrode method uses a plasma heat source to melt the raw material rods. The melt is spheroidized and condensed into powder under the action of centrifugal force. The particle size of the powder prepared by this method is limited by the speed of the high-speed motor, and the yield of fine powder is low. The traditional inert gas atomization method uses a water-cooled copper crucible for smelting. The melt is crushed and cooled into powder by inert gas. The powder particle size is large and the energy consumption cost of the whole process is high. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of high preparation cost, large powder particle size and low yield of titanium or titanium alloy powder prepared by the prior art, thereby providing a fine spherical titanium or titanium alloy powder and its preparation method and application.

[0005] The present invention provides a method for preparing fine spherical titanium or titanium alloy powder, comprising the following steps:

[0006] 1) The atomizing powder making equipment is first vacuumed and then filled with inert gas;

[0007] 2) Two raw wires are connected to the positive and negative electrodes of the arc power supply respectively, and then enter the guide tube through the wire feeding device, forming a raw wire contact point at the outlet end of the guide tube to generate arc molten droplets;

[0008] The raw material wire is titanium or titanium alloy wire;

[0009] 3) atomizing the arc molten droplets described in step 2) by at least two atomizing gas streams to obtain the fine spherical titanium or titanium alloy powder;

[0010] The atomized airflow converges to form an airflow focus which is concentrated at the same point as the contact point of the raw material wire described in step 2).

[0011] The present invention does not specifically limit titanium or titanium alloys, and is applicable to all titanium or titanium alloy materials, for example, TA1, TA4, and TC4 that are commercially available may be selected but are not limited thereto.

[0012] Preferably, in step 1), the vacuum degree in the atomizing powder making equipment is 1×10 -4 -1x10 -3 Pa;

[0013] And / or, in step 1), an inert gas is charged to keep the gas pressure in the atomizing powder making equipment at 0.1-0.5 MPa;

[0014] The inert gas includes argon;

[0015] And / or, in step 3), the arc molten droplets described in step 2) are atomized by multiple atomizing gas flows.

[0016] The present invention does not impose a specific limitation on the number of multiple atomizing gas flows, and different numbers of atomizing gas flows can be selected according to actual needs. Typically, three atomizing gas flows are used to atomize the arc molten droplets described in step 2).

[0017] Preferably, the diameter of the raw material wire in step 2) is 1-2 mm;

[0018] The voltage of the arc power supply is 28-35V, and the current is 180-220A;

[0019] The two raw wires are directly or indirectly connected to the positive and negative electrodes of the arc power source to form a current path;

[0020] Optionally, the two raw material wires are in contact with the conductive blocks respectively, and are connected to the positive and negative electrodes of the arc power supply through the conductive blocks.

[0021] Preferably, the wire feeding speed of the wire feeding device in step 2) is 0.02-0.04 m / min;

[0022] The wire feeding device has a straightening function.

[0023] Preferably, the angle between the guide tubes in step 2) is 50-70°;

[0024] The guide tube in step 2) is made of insulating material;

[0025] Preferably, the guide tube is made of at least one material selected from alumina and boron nitride.

[0026] Preferably, the atomizing gas in step 3) is sprayed out through an atomizing nozzle;

[0027] The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space, and the outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle;

[0028] Preferably, a Laval tube type atomizing nozzle is provided inside the atomizing nozzle, and the atomizing gas flows through the Laval tube type atomizing nozzle and is ejected from the atomizing nozzle;

[0029] The atomizing nozzle is selected from at least one of an annular gap atomizing nozzle and an annular hole atomizing nozzle.

[0030] It can be understood that when the atomizing air flows through the Laval tube type atomizing nozzle, the airflow will be accelerated, and then the accelerated atomizing airflow is ejected from the atomizing nozzle.

[0031] Preferably, the atomizing air flow pressure is 1-3 MPa;

[0032] The atomizing gas flow is an inert gas flow;

[0033] Preferably, the atomizing gas flow is argon gas flow.

[0034] Preferably, the interior of the atomizing powder making equipment in step 1) includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank.

[0035] Optionally, after obtaining the fine spherical titanium or titanium alloy powder in step 3), the step further includes the steps of screening and vacuum packaging the fine spherical titanium or titanium alloy powder;

[0036] At least two atomizing air flows are ejected from the atomizing nozzle, and the ejected atomizing air flows converge to form an air flow focus. The atomizing process includes at least two atomizing air flows in the atomizing nozzle breaking, dispersing and cooling the arc molten droplets in step 2) to finally obtain atomized powder.

[0037] The present invention provides a method for preparing micro-spherical titanium or titanium alloy powder.

[0038] The present invention also provides an application of the fine spherical titanium or titanium alloy powder prepared by the above-mentioned preparation method in additive manufacturing.

[0039] The technical solution of the present invention has the following advantages:

[0040] The preparation method of fine spherical titanium or titanium alloy powder provided by the present invention comprises the following steps: 1) vacuumizing an atomizing powder making device and then filling it with an inert gas; 2) connecting two raw material wires to the positive and negative electrodes of an arc power source respectively, and then entering a guide tube through a wire feeding device, forming a raw material wire contact point at the outlet end of the guide tube, and generating arc molten droplets; the raw material wire is titanium or titanium alloy wire; 3) atomizing the arc molten droplets described in step 2) by at least two atomizing airflows to obtain the fine spherical titanium or titanium alloy powder; wherein the atomizing airflows converge to form an airflow focus and the raw material wire contact point described in step 2) are concentrated at the same point. The present invention transmits the raw material wire through a wire feeding device, and makes the two contact to generate arc melting to form molten droplets. At the same time, the strong airflow with the focus of the airflow and the contact point of the raw material wire concentrated at the same point directly crushes the arc molten droplets to form fine powder. There is no distance difference between the focus of the airflow and the arc molten droplets, and there is no time difference during atomization. Atomization is completed at the same time as the arc molten droplets are formed, which can ensure the superheat of the arc molten droplets, improve the atomization efficiency, and improve the yield of titanium or titanium alloy powder. The obtained titanium or titanium alloy powder has a small particle size and a uniform particle size distribution, and further ensures that the titanium or titanium alloy powder is not easily contaminated and has a low oxygen addition amount. It avoids the problem that the temperature of the molten droplets decreases during the falling process, the atomization efficiency decreases during re-atomization, and the quality of the prepared titanium or titanium alloy powder is poor. At the same time, the method of the present invention greatly reduces the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 It is a schematic diagram of the equipment for the method for preparing fine spherical titanium or titanium alloy powder of the present invention;

[0043] Description of reference numerals:

[0044] 1. Raw material rack, 2. Wire feeding device, 3. Guide tube, 4. Atomizing nozzle, 5. Atomizing tower, 6. Powder collecting tank. DETAILED DESCRIPTION

[0045] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0046] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0047] Example 1

[0048] This embodiment provides a method for preparing fine spherical titanium alloy powder, comprising the following steps:

[0049] 1) For atomization powder making equipment (such as Figure 1 As shown in the figure, vacuum treatment is first performed, and the vacuum degree reaches 2×10 -4 Pa, high-purity argon is used as the protective atmosphere to fill the atomizing powder making equipment, so that the gas pressure in the atomizing powder making equipment is maintained at 0.3MPa to prevent the titanium alloy wire from being oxidized during the melting and atomizing process. The interior of the atomizing powder making equipment includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank;

[0050] 2) Two TA1 titanium alloy wires with a diameter of 2 mm are respectively contacted with the conductive blocks, and connected to the positive and negative electrodes of the arc power supply through the conductive blocks. The voltage of the arc power supply is 30 V and the current is 200 A; then they enter the alumina guide tube through the wire feeding device, the wire feeding speed is 0.02 m / min, the angle between the guide tubes is 60°, and a titanium alloy wire contact point is formed at the outlet end of the guide tube to generate arc molten droplets;

[0051] 3) The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space. The outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle; a Laval tube-type atomizing nozzle is arranged inside the atomizing nozzle, and three atomizing gas flows are ejected from the atomizing nozzle through the Laval tube-type atomizing nozzle to atomize the arc molten droplets described in step 2) to obtain the fine spherical titanium alloy powder, and the atomizing gas flow is a high-purity argon gas flow, and the atomizing gas flow pressure is 2MPa;

[0052] The high-purity argon gas flow converges to form a flow focus which is concentrated at the same point as the contact point of the titanium alloy wire described in step 2).

[0053] Example 2

[0054] This embodiment provides a method for preparing fine spherical titanium alloy powder, comprising the following steps:

[0055] 1) The atomizing powder making equipment is first vacuumized to a vacuum degree of 2×10 -4Pa, high-purity argon is used as the protective atmosphere to fill the atomizing powder making equipment, so that the gas pressure in the atomizing powder making equipment is maintained at 0.3MPa to prevent the titanium alloy wire from being oxidized during the melting and atomizing process. The interior of the atomizing powder making equipment includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank;

[0056] 2) Two TA1 titanium alloy wires with a diameter of 1 mm are respectively contacted with the conductive blocks, and connected to the positive and negative electrodes of the arc power supply through the conductive blocks. The voltage of the arc power supply is 30 V and the current is 200 A; then they enter the alumina guide tube through the wire feeding device, the wire feeding speed is 0.02 m / min, the angle between the guide tubes is 60°, and a titanium alloy wire contact point is formed at the outlet end of the guide tube to generate arc molten droplets;

[0057] 3) The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space. The outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle; a Laval tube-type atomizing nozzle is arranged inside the atomizing nozzle, and three atomizing gas flows are ejected from the atomizing nozzle through the Laval tube-type atomizing nozzle to atomize the arc molten droplets described in step 2) to obtain the fine spherical titanium alloy powder, and the atomizing gas flow is a high-purity argon gas flow, and the atomizing gas flow pressure is 2MPa;

[0058] The high-purity argon gas flow converges to form a flow focus which is concentrated at the same point as the contact point of the titanium alloy wire described in step 2).

[0059] Example 3

[0060] This embodiment provides a method for preparing fine spherical titanium alloy powder, comprising the following steps:

[0061] 1) The atomizing powder making equipment is first vacuumized to a vacuum degree of 2×10 -4 Pa, high-purity argon is used as the protective atmosphere to fill the atomizing powder making equipment, so that the gas pressure in the atomizing powder making equipment is maintained at 0.3MPa to prevent the titanium alloy wire from being oxidized during the melting and atomizing process. The interior of the atomizing powder making equipment includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank;

[0062] 2) Two TC4 titanium alloy wires with a diameter of 2 mm are respectively contacted with the conductive blocks, and connected to the positive and negative electrodes of the arc power supply through the conductive blocks. The voltage of the arc power supply is 30 V and the current is 200 A; then they enter the alumina guide tube through the wire feeding device, the wire feeding speed is 0.02 m / min, the angle between the guide tubes is 60°, and a titanium alloy wire contact point is formed at the outlet end of the guide tube to generate arc molten droplets;

[0063] 3) The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space. The outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle; a Laval tube-type atomizing nozzle is arranged inside the atomizing nozzle, and three atomizing gas flows are ejected from the atomizing nozzle through the Laval tube-type atomizing nozzle to atomize the arc molten droplets described in step 2) to obtain the fine spherical titanium alloy powder, and the atomizing gas flow is a high-purity argon gas flow, and the atomizing gas flow pressure is 2MPa;

[0064] The high-purity argon gas flow converges to form a flow focus which is concentrated at the same point as the contact point of the titanium alloy wire described in step 2).

[0065] Example 4

[0066] This embodiment provides a method for preparing fine spherical titanium alloy powder, comprising the following steps:

[0067] 1) The atomizing powder making equipment is first vacuumed to a vacuum degree of 1x10 -4 Pa, high-purity argon is used as the protective atmosphere to fill the atomizing powder making equipment, so that the gas pressure in the atomizing powder making equipment is maintained at 0.1MPa to prevent the titanium alloy wire from being oxidized during the melting and atomizing process. The interior of the atomizing powder making equipment includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank;

[0068] 2) Two TA4 titanium alloy wires with a diameter of 1.5 mm are respectively contacted with the conductive blocks, and connected to the positive and negative electrodes of the arc power supply through the conductive blocks. The voltage of the arc power supply is 28 v and the current is 180 A; then they enter the carbon nitride guide tube through the wire feeding device, the wire feeding speed is 0.04 m / min, the angle between the guide tubes is 50°, and a titanium alloy wire contact point is formed at the outlet end of the guide tube to generate arc molten droplets;

[0069] 3) The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space. The outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle; a Laval tube-type atomizing nozzle is arranged inside the atomizing nozzle, and three atomizing gas flows are ejected from the atomizing nozzle through the Laval tube-type atomizing nozzle to atomize the arc molten droplets described in step 2) to obtain the fine spherical titanium alloy powder, and the atomizing gas flow is a high-purity argon gas flow, and the atomizing gas flow pressure is 1 MPa;

[0070] The high-purity argon gas flow converges to form a flow focus which is concentrated at the same point as the contact point of the titanium alloy wire described in step 2).

[0071] Example 5

[0072] This embodiment provides a method for preparing fine spherical titanium alloy powder, comprising the following steps:

[0073] 1) The atomizing powder making equipment is first vacuumed to a vacuum degree of 1x10 -3 Pa, high-purity argon is used as the protective atmosphere to fill the atomizing powder making equipment, so that the gas pressure in the atomizing powder making equipment is maintained at 0.5MPa to prevent the titanium alloy wire from being oxidized during the melting and atomizing process. The interior of the atomizing powder making equipment includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank;

[0074] 2) Two TA1 titanium alloy wires with a diameter of 1.5 mm are respectively contacted with the conductive blocks, and connected to the positive and negative electrodes of the arc power supply through the conductive blocks. The voltage of the arc power supply is 35 V and the current is 220 A; then they enter the alumina guide tube through the wire feeding device, the wire feeding speed is 0.03 m / min, the angle between the guide tubes is 70°, and a titanium alloy wire contact point is formed at the outlet end of the guide tube to generate arc molten droplets;

[0075] 3) The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space. The outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle; a Laval tube-type atomizing nozzle is arranged inside the atomizing nozzle, and three atomizing gas flows are ejected from the atomizing nozzle through the Laval tube-type atomizing nozzle to atomize the arc molten droplets described in step 2) to obtain the fine spherical titanium alloy powder, and the atomizing gas flow is a high-purity argon gas flow, and the atomizing gas flow pressure is 3 MPa;

[0076] The high-purity argon gas flow converges to form a flow focus which is concentrated at the same point as the contact point of the titanium alloy wire described in step 2).

[0077] Comparative Example 1

[0078] This comparative example provides a method for preparing fine spherical titanium alloy powder, which differs from Example 1 in that in step 3), the high-purity argon gas flows converge to form a flow focus 2 cm below the contact point of the TA1 titanium alloy wire in step 2).

[0079] Test Case

[0080] Relevant tests were carried out on the fine spherical titanium alloy powders obtained in Examples 1-5 and Comparative Example 1, and the yield of the fine spherical titanium alloy powder was determined according to the mass ratio of the titanium alloy before and after the formation of the fine spherical powder; the average particle size of the fine spherical titanium alloy powder was analyzed by a particle size analyzer, and the percentage of powder with a particle size of ≤45μm in the powder was counted, and the results are shown in Table 1; the mass change of the fine spherical titanium alloy powder before and after preparation was tested by a weighing method, and the yield was calculated, and the results are shown in Table 1; the oxygen addition amount of the fine spherical titanium alloy powder was determined by a nitrogen oxygen analyzer, and the measurement results are shown in Table 1.

[0081] Table 1

[0082]

[0083] Obviously, the above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for preparing fine spherical titanium or titanium alloy powder, characterized in that: The following steps are involved: 1) The atomizing powder making equipment is first vacuumed and then filled with inert gas; 2) Two raw wires are connected to the positive and negative electrodes of the arc power supply respectively, and then enter the guide tube through the wire feeding device, forming a raw wire contact point at the outlet end of the guide tube to generate arc molten droplets; The raw material wire is titanium or titanium alloy wire; 3) atomizing the arc molten droplets described in step 2) by at least two atomizing gas streams to obtain the fine spherical titanium or titanium alloy powder; The atomized airflow converges to form an airflow focus which is concentrated at the same point as the contact point of the raw material wire described in step 2).

2. The method for preparing fine spherical titanium or titanium alloy powder according to claim 1, characterized in that: Step 1) The vacuum degree in the atomizing powder making equipment is 1x10 -4 -1x10 -3 Pa; And / or, in step 1), an inert gas is charged to keep the gas pressure in the atomizing powder making equipment at 0.1-0.5 MPa; The inert gas includes argon; And / or, in step 3), the arc molten droplets described in step 2) are atomized by multiple atomizing gas flows.

3. The method for preparing fine spherical titanium or titanium alloy powder according to claim 1 or 2, characterized in that: The diameter of the raw material wire in step 2) is 1-2 mm; The voltage of the arc power supply is 28-35V, and the current is 180-220A; The two raw wires are directly or indirectly connected to the positive and negative electrodes of the arc power source to form a current path; Optionally, the two raw material wires are in contact with the conductive blocks respectively, and are connected to the positive and negative electrodes of the arc power supply through the conductive blocks.

4. The method for preparing fine spherical titanium or titanium alloy powder according to any one of claims 1 to 3, characterized in that: The wire feeding speed of the wire feeding device in step 2) is 0.02-0.04 m / min; The wire feeding device has a straightening function.

5. The method for preparing fine spherical titanium or titanium alloy powder according to any one of claims 1 to 4, characterized in that: The angle between the guide tubes in step 2) is 50-70°; The guide tube in step 2) is made of insulating material; Preferably, the guide tube is made of at least one material selected from alumina and boron nitride.

6. The method for preparing fine spherical titanium or titanium alloy powder according to any one of claims 1 to 5, characterized in that: The atomized gas in step 3) is sprayed out through an atomizing nozzle; The guide tube in step 2) is built into the central hole of the atomizing nozzle and is tightly coupled with the atomizing nozzle in space, and the outlet end of the guide tube forms a raw material wire contact point located outside the central hole of the atomizing nozzle; Preferably, a Laval tube type atomizing nozzle is provided inside the atomizing nozzle, and the atomizing gas flows through the Laval tube type atomizing nozzle and is ejected from the atomizing nozzle; The atomizing nozzle is selected from at least one of an annular gap atomizing nozzle and an annular hole atomizing nozzle.

7. The method for preparing fine spherical titanium or titanium alloy powder according to any one of claims 1 to 6, characterized in that: The atomizing air flow pressure is 1-3MPa; The atomizing gas flow is an inert gas flow; Preferably, the atomizing gas flow is argon gas flow.

8. The method for preparing fine spherical titanium or titanium alloy powder according to any one of claims 1 to 7, characterized in that: The interior of the atomizing powder making equipment in step 1) includes a raw material rack, a wire feeding device, a guide tube, an atomizing nozzle, an atomizing tower, and a powder collecting tank.

9. The preparation method according to any one of claims 1 to 8 is used to prepare fine spherical titanium or titanium alloy powder.

10. Application of the fine spherical titanium or titanium alloy powder prepared by the preparation method according to any one of claims 1 to 8 in additive manufacturing.

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