Method for reducing oxygen content of micro titanium and titanium alloy powder

Abstract

The invention relates to a method for reducing the oxygen content of micro titanium and titanium alloy powder. The method comprises the following steps: (1) uniformly mixing titanium and titanium alloy powder, metal calcium and yttrium oxide powder; (2) placing the mixed powder obtained in the step (1) in a vacuum or argon atmosphere for high-temperature reaction; and (3) sequentially carrying out acid pickling, water washing and vacuum drying on the product obtained in the step (2) to obtain the low-oxygen titanium and titanium alloy powder. The method for reducing the oxygen content of the fine titanium and titanium alloy powder aims at solving the problem that the oxygen content of the fine titanium and titanium alloy powder prepared through a hydrogenation dehydrogenation method and a plasma spheroidizing method and the oxygen content of the fine titanium and titanium alloy powder recycled through 3D printing are high, and the prepared powder is low in oxygen content, high in powder collecting rate and suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of rare metal material processing, and in particular relates to a method for reducing the oxygen content of fine titanium and titanium alloy powders. Background Art

[0002] Titanium and its alloys possess advantages such as high specific strength, excellent corrosion resistance, strong heat resistance, and good biocompatibility, and are therefore crucial for applications in aviation, aerospace, medicine, and the chemical industry. With the advancement of additive manufacturing and metal injection molding technologies, the demand for low-oxygen titanium and titanium alloy powders is rapidly increasing. However, due to titanium's strong affinity for oxygen and the large surface area of ​​titanium and titanium alloy micropowders (0.5-10 μm) and fine powders (10-53 μm), micronized titanium and titanium alloy powders prepared by methods such as hydrogenation and dehydrogenation and plasma spheroidization typically have high oxygen contents, making them difficult to meet the requirements of additive manufacturing and metal injection molding. Furthermore, during the additive manufacturing process, the oxygen content of recycled and reused powders increases with the number of prints. High oxygen content can negatively impact the performance of titanium alloy parts in two key ways: Excessive oxygen content can reduce the ductility, corrosion resistance, and notch sensitivity of micronized titanium and titanium alloy parts; Furthermore, the presence of an oxide layer on the powder surface can affect its flowability and laser absorptivity, ultimately impacting part performance. Therefore, reducing the oxygen content of titanium and titanium alloy powders is not only the key to ensuring the performance of titanium alloy parts, but also an important means to achieve the recycling and reuse of titanium powder.

[0003] Currently, calcium thermal reduction is a common method for reducing the oxygen content of titanium and titanium alloys. Calcium metal has a stronger reducing property than titanium and can undergo a reduction reaction with titanium at high temperatures to displace the oxygen in titanium. It is often used as a reducing agent to reduce the oxygen content of titanium powder using thermochemical reduction methods. JM Oh et al. used a non-contact calcium reduction method to reduce the oxygen content of titanium powder from 2200 ppm to 820 ppm. However, the mass ratio of calcium to titanium powder reached (0.5-1):1. Due to the high price of calcium, this resulted in a high cost for preparing low-oxygen titanium powder using the non-contact calcium reduction method (Mater. Trans. 2012, 53:1075-1077).

[0004] The contact calcium reduction method can reduce the calcium content, but for fine titanium powders of 0.5 to 53 μm, the powder will significantly agglomerate or even sinter into lumps during the oxygen reduction process, reducing the powder yield. Li Qingkui et al. used contact liquid calcium to reduce the oxygen content of titanium powder and added CaO as a dispersant to prevent powder sintering and agglomeration, reducing the oxygen content of irregular fine titanium powder to below 1000 ppm. However, the CaO used in this method generally has a coarse particle size and low purity, which can easily lead to problems such as uneven mixing and the introduction of impurities. In addition, the irregular titanium powder used as the raw material has problems such as large powder specific surface area, low oxygen reduction limit, and subsequent easy oxidation (CN 116904788 A). Summary of the Invention

[0005] In response to the above problems, the present invention provides a method for reducing the oxygen content of fine titanium and titanium alloy powders. This method can be used to deoxidize fine titanium and titanium alloy powders with a particle size of 0.5 to 53 μm. The prepared titanium and titanium alloy powders have low oxygen content, high purity and powder recovery rate, and can meet the requirements of powder metallurgy, additive manufacturing, metal injection molding and other technologies for the oxygen content of raw materials.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for reducing the oxygen content of fine titanium and titanium alloy powders comprises the following steps:

[0008] (1) uniformly mixing titanium and titanium alloy powder, metallic calcium and yttrium oxide powder;

[0009] (2) placing the mixed powder obtained in step (1) in a vacuum or inert atmosphere for high temperature reaction;

[0010] (3) The product obtained in step (2) is sequentially acid-washed, water-washed, and vacuum-dried to obtain low-oxygen titanium and titanium alloy powder.

[0011] According to the above-mentioned method for reducing the oxygen content of fine titanium and titanium alloy powders, the titanium and titanium alloy described in step (1) are any one or more of pure titanium, TA7, TA11, TC4, TC6, TC11, TB6, and have a particle size of 0.5 to 53 μm.

[0012] According to the above-mentioned method for reducing the oxygen content of fine titanium and titanium alloy powders, the purity of the metallic calcium described in step (1) is ≥99%, the particle size is 0.1-5 mm, and the morphology is any one or more of powder, chips or granules.

[0013] According to the above-mentioned method for reducing the oxygen content of fine titanium and titanium alloy powders, the mass ratio of metallic calcium to titanium and titanium alloy powders in step (1) is (0.03-0.3):1.

[0014] According to the above-mentioned method for reducing the oxygen content of fine titanium and titanium alloy powders, the yttrium oxide powder described in step (1) has a purity of ≥99% and a particle size of 0.01 to 5 μm.

[0015] According to the above-mentioned method for reducing the oxygen content of fine titanium and titanium alloy powders, the mass ratio of the yttrium oxide powder to the titanium and titanium alloy powder in step (1) is (0.3-2):1.

[0016] According to the above-mentioned method for reducing the oxygen content of fine titanium and titanium alloy powders, the high-temperature reaction in step (2) is performed at a reaction temperature of 850 to 1200° C. and a reaction time of 0.5 to 12 hours.

[0017] According to the above method for reducing the oxygen content of fine titanium and titanium alloy powders, the acid used for pickling in step (3) is any one or more of hydrochloric acid, sulfuric acid, and nitric acid, with a concentration range of 1% to 5%.

[0018] The beneficial effects of the present invention are:

[0019] The invention is suitable for reducing oxygen of fine titanium and titanium alloy powders with a particle size of 0 to 53 μm. The prepared titanium and titanium alloy powders have no obvious sintering problem, low oxygen content, high purity and powder recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The SEM morphology of 15-53 μm TC4 powder after deoxidation in Example 1;

[0021] Figure 2 This is the SEM morphology of 5-20 μm TC4 powder after oxygen reduction in Example 2. DETAILED DESCRIPTION

[0022] The technical solutions of the present invention are described clearly and completely below in conjunction with embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0023] Example 1

[0024] A method for reducing the oxygen content of fine titanium and titanium alloy powders comprises the following steps:

[0025] (1) Spherical TC4 powder with an oxygen content of 3400 ppm and a particle size of 15 to 53 μm prepared by radio frequency plasma spheroidization, metallic calcium particles with a purity of ≥99% and a particle size of 0.2 to 2 μm, and yttrium oxide powder with a purity of ≥99% and a particle size of 0.5 to 1 μm were uniformly mixed in a mass ratio of 1:0.09:1;

[0026] (2) placing the mixed powder obtained in step (1) in a vacuum sintering furnace, heating it to 1000° C. in an argon atmosphere, and reacting it at high temperature for 3 h;

[0027] (3) After cooling, the product obtained in step (2) was taken out, first washed with 1wt% dilute hydrochloric acid for 30 minutes, then washed with deionized water for 5 times, and vacuum dried to obtain low-oxygen TC4 powder. The oxygen content of the powder was measured using an ONH analyzer, as shown in Table 1. The morphology of the powder was observed using a scanning electron microscope, as shown in Table 1. Figure 1 shown.

[0028] Example 2

[0029] A method for reducing the oxygen content of fine titanium and titanium alloy powders comprises the following steps:

[0030] (1) TC4 powder with an oxygen content of 6000 ppm and a particle size of 5 to 20 μm prepared by a hydrogenation-dehydrogenation method, metallic calcium particles with a purity of ≥99% and a particle size of 0.2 to 2 μm, and yttrium oxide powder with a purity of ≥99% and a particle size of 0.5 to 1 μm were uniformly mixed in a mass ratio of 1:0.12:1.5;

[0031] (2) placing the mixed powder obtained in step (1) in a vacuum sintering furnace, heating it to 1000° C. in an argon atmosphere, and reacting it at high temperature for 3 h;

[0032] (3) After cooling, the product obtained in step (2) was taken out, first washed with 2wt% dilute hydrochloric acid for 30 minutes, then washed with deionized water for 5 times, and vacuum dried to obtain low-oxygen TC4 powder. The oxygen content of the powder was measured using an ONH analyzer, as shown in Table 1. The powder morphology was observed using a scanning electron microscope, as shown in Table 1. Figure 2 shown.

[0033] Example 3

[0034] A method for reducing the oxygen content of fine titanium and titanium alloy powders comprises the following steps:

[0035] (1) Pure titanium powder with an oxygen content of 2400 ppm and a particle size of 5 to 20 μm, metallic calcium particles with a purity of ≥98% and a particle size of 0.2 to 1 μm, and yttrium oxide powder with a purity of ≥99% and a particle size of 0.5 to 1 μm were mixed uniformly in a mass ratio of 1:0.09:1;

[0036] (2) placing the mixed powder obtained in step (1) in a vacuum sintering furnace, heating it to 950° C. in a vacuum environment for reaction, and keeping it at this temperature for 2 h;

[0037] (3) After cooling, the product obtained in step (2) was taken out, first washed with 2 wt% dilute hydrochloric acid for 60 min, then washed with deionized water 5 times, and vacuum dried to obtain low-oxygen pure titanium powder. The oxygen content was measured using an ONH analyzer, as shown in Table 1.

[0038] Comparative Example 1

[0039] A method for reducing the oxygen content of fine titanium and titanium alloy powders comprises the following steps:

[0040] (1) Spherical TC4 powder with an oxygen content of 3400 ppm and a particle size of 15 to 53 μm prepared by radio frequency plasma spheroidization and metallic calcium particles with a purity of ≥99% and a particle size of 0.2 to 2 μm were mixed uniformly in a mass ratio of 1:0.09;

[0041] (2) placing the mixed powder obtained in step (1) in a vacuum sintering furnace, heating it to 1000° C. in an argon atmosphere, and reacting it at high temperature for 3 h;

[0042] (3) After cooling, the product obtained in step (2) was taken out, first washed with 1 wt% dilute hydrochloric acid for 30 min, then washed with deionized water for 5 times, and vacuum dried to obtain TC4 powder.

[0043] Table 1 Oxygen content and powder yield of powders prepared in various embodiments

[0044]

[0045] 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 technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for reducing the oxygen content of fine titanium and titanium alloy powders, characterized in that: The steps include: (1) uniformly mixing titanium and titanium alloy powder, metallic calcium and yttrium oxide powder; (2) placing the mixed powder obtained in step (1) in a vacuum or argon atmosphere for high-temperature reaction; (3) The product obtained in step (2) is sequentially acid-washed, water-washed, and vacuum-dried to obtain low-oxygen titanium and titanium alloy powder.

2. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The titanium and titanium alloy powder described in step (1) is any one or more of pure titanium, TA7, TA11, TC4, TC6, TC11, and TB6, and has a particle size of 0.5 to 53 μm.

3. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The purity of the metallic calcium in step (1) is ≥99%, the particle size is 0.1-5 mm, and the morphology is any one or more of powder, crumb or granular.

4. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The mass ratio of metallic calcium to titanium and titanium alloy powder described in step (1) is (0.03-0.3):

1.

5. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The yttrium oxide powder described in step (1) has a purity of ≥99% and a particle size of 0.01 to 5 μm.

6. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The mass ratio of the yttrium oxide powder to the titanium and titanium alloy powder in step (1) is (0.3-2):

1.

7. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The high temperature reaction in step (2) is carried out at a reaction temperature of 850 to 1200° C. and a reaction time of 0.5 to 12 hours.

8. The method for reducing the oxygen content of fine titanium and titanium alloy powders according to claim 1, characterized in that: The acid used for pickling in step (3) is any one or more of hydrochloric acid, nitric acid or sulfuric acid, with a concentration range of 1% to 5%.

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