A low-oxygen non-stoichiometric titanium hydride powder and a continuous preparation method thereof

Abstract

The present invention belongs to the technical field of titanium-based compound powders, and specifically discloses a low-oxygen non-stoichiometric titanium hydride powder and a continuous preparation method thereof. The preparation method is specifically as follows: raw titanium is added to a continuous vacuum atmosphere rotary kiln, and after hydrogen mixed gas is introduced until the pressure in the furnace is stable, the raw titanium passes through a preheating zone, a primary hydrogenation zone, a transition zone, a dehydrogenation zone, a transition zone, a secondary hydrogenation zone, and a low-temperature cooling zone in sequence, and finally is subjected to air flow crushing and classification. By optimizing the process parameters such as the secondary hydrogenation and primary dehydrogenation temperatures, the length of each zone, and the inlet gas being a mixed gas of high-purity hydrogen and TiCl4, a brittle, low-oxygen non-stoichiometric TiH 1.924 The powder can be used to prepare titanium alloy products with excellent processing formability and mechanical properties; and the method has continuous production capacity, which not only greatly improves production efficiency but also reduces production risks.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium-based compound powders, and in particular relates to low-oxygen non-stoichiometric titanium hydride powder and a continuous preparation method thereof. Background Art

[0002] Titanium alloy powder metallurgy is an advanced manufacturing technology that prepares titanium alloy powder into parts through forming and sintering processes. These parts are widely used in chemical, aerospace, automotive and medical fields. Compared with traditional titanium alloy casting process, titanium alloy powder metallurgy technology materials have many advantages such as high raw material utilization and low manufacturing cost. At present, the commonly used methods for titanium alloy powder metallurgy include the following: (1) Hydrogenation dehydrogenation (HDH) method. This method uses electrolytic titanium or sponge titanium as raw material, with low cost and simple process, but the powder particle size range is wide and the O and N contents are high; (2) Atomization method. This method uses titanium wire as raw material. The powder prepared has low impurity content and good sphericity, but the particle size is coarse and the process is complex and the cost is high; (3) Pre-alloying method. This method uses partially or fully alloyed titanium alloy powder as raw material. The powder prepared has high purity and low impurity content such as oxygen, nitrogen and hydrogen, but poor sintering performance, coarse particle size and wide distribution; (4) Radio frequency plasma spheroidization method. This method uses titanium hydride particles as raw material. The spherical powder prepared has good surface morphology and high purity, but the production technology is difficult to achieve; (5) Mixed element method. The powder particle size prepared by this method is controllable, but there are problems such as poor density, high interstitial element content, and poor sintering micromorphology. There are also some specific titanium alloy powder metallurgy methods, such as electrolysis, atmosphere reduction, mechanical synthesis and gas atomization. In practical applications, choosing the right powder metallurgy method and raw materials is crucial to controlling the properties of titanium alloys. By optimizing process parameters and processing steps, the quality of titanium alloy powder can be further improved, thereby preparing high-performance titanium alloy parts that meet specific application requirements.

[0003] In the HDH method described above, the products prepared with titanium hydride as raw material are superior to traditional titanium powder metallurgy in terms of cost and performance, expanding the application of titanium alloy products in high-end fields. Titanium hydride can effectively improve the density of products, which is one of its outstanding advantages. This is mainly due to (1) it is a brittle material, which is more likely to undergo brittle fracture during the pressing process and obtain small-sized particles, so that it can fill the gaps between large particles, while increasing the sintering surface area and improving the density of products; (2) in the early sintering stage of product preparation, the activation effect of titanium hydride in the hydrogen release stage promotes the later sintering and can also improve the density. At the same time, the control of oxygen content in titanium hydride has an important influence on the performance of titanium alloys. Appropriate oxygen content can optimize the microstructure and mechanical properties of the alloy, but when oxygen exceeds a certain limit, it will lead to an increase in the phase transition temperature of the raw material, induce the formation of martensite phase or generate titanium oxide clusters, resulting in a sharp decrease in the plasticity, fracture toughness, cold formability and other properties of titanium alloy products. Therefore, the control of oxygen content is one of the key issues that need to be solved in the synthesis of titanium hydride raw materials.

[0004] The range of x in titanium hydride TiHx is mostly 1.5-2.0. When x is 2.0, it is called stoichiometric titanium hydride, and when x is less than 2.0, it is called non-stoichiometric titanium hydride. At present, the commonly used titanium hydride preparation schemes are intermittent reaction synthesis under high-pressure hydrogen and 300-600°C. Stoichiometric titanium hydride TiH2 can be synthesized under long-term high-pressure conditions. The synthesis reaction is relatively simple, but this raw material has a high dehydrogenation activation energy required during the sintering process when used for HDH to prepare titanium alloy products. The rate of hydrogen release is too high and the shrinkage rate is large, which easily leads to cracking of the product. When x is around 1.5, non-stoichiometric titanium hydride has the disadvantages of high metallic properties and is not easy to break and dehydrogenate. Therefore, considering the advantages and disadvantages of each, the second problem to be solved is to select non-stoichiometric titanium hydride with a suitable x value as HDH raw material to take into account the characteristics of densification, avoid shrinkage, and easy to break and process.

[0005] There are two main methods for preparing non-stoichiometric titanium hydride: sponge titanium hydrogen absorption and stoichiometric titanium hydride hydrogenation and dehydrogenation. The former has a short process and consumes less energy, but its titanium hydride powder is not easy to ball mill, while the dehydrogenation process of the latter has the advantages of cleaning the surface and reducing the oxygen content. Both have their advantages and disadvantages. In addition, the prior art commonly uses a high-pressure intermittent heating furnace for processing titanium hydride, which has low production efficiency and is difficult to achieve industrial continuous production. How to solve this problem is also the focus of this application. Summary of the invention

[0006] The present invention optimizes the selection and ratio of synthetic raw materials in combination with the reaction mechanism, controls the rates of hydrogenation and dehydrogenation processes and other process parameters, etc., and can prepare non-stoichiometric TiHx powder with a suitable x value, easy crushing and processing, and low oxygen content, and can achieve continuous production. The prepared titanium alloy products have excellent processing formability and mechanical properties, and solve the problems existing in the prior art.

[0007] Firstly, the present invention provides a continuous preparation method of low-oxygen non-stoichiometric titanium hydride powder, which is specifically as follows: raw titanium is added into a continuous vacuum atmosphere rotary kiln, hydrogen mixed gas is introduced until the pressure in the furnace is stable, and the raw titanium passes through a primary hydrogenation zone, a dehydrogenation zone, a secondary hydrogenation zone, a low-temperature cooling zone in sequence, and finally is crushed and classified by air flow.

[0008] Furthermore, in the titanium hydride TiHx powder, 1.9≤x<2. Studies have shown that in the process of preparing titanium hydride by combining titanium and hydrogen, titanium gradually undergoes a phase change process of α→α+β→α+β+δ→α+δ→δ as the hydrogen content increases. The δ phase is a brittle phase and is more conducive to the crushing of titanium hydride. The non-stoichiometric TiHx powder prepared by controlling 1.9≤x<2 in the present invention has excellent crushing performance, taking into account both processability and high activity.

[0009] In a preferred embodiment, when x is 1.924, the non-stoichiometric TiHx powder has the best combination of crushability and activity.

[0010] Furthermore, the raw titanium includes but is not limited to at least one of sponge titanium, turned titanium chips, titanium alloy chips, spherical titanium powder, and spherical titanium alloy powder.

[0011] The oxygen content of the raw titanium does not exceed 0.2%, and the particle size is ≥ 5 mesh.

[0012] Furthermore, the temperature of the primary hydrogenation zone is 500-700°C. The hydrogenation reaction of the raw titanium is an exothermic reaction, so the temperature of the primary hydrogenation zone does not need to be too high, and it is sufficient to maintain the normal reaction. When the temperature is low, the reaction rate is slow, and when the temperature is too high, decomposition of titanium hydride occurs.

[0013] Preferably, the temperature of the primary hydrogenation zone is 550-650°C, and the optional heating method is resistance heating, etc.; the length accounts for 20-30% of the length of the rotary kiln heating area.

[0014] Furthermore, the temperature of the dehydrogenation zone is 700-850℃, and its length accounts for 15-25% of the length of the rotary kiln heating zone. Titanium that has undergone hydrogenation once will undergo dehydrogenation in this zone. Since the concentration of hydrogen in this zone is still high, what actually occurs is a reversible reaction of decomposition and generation of titanium hydride. When the temperature is too high, not only will titanium sintering occur, but the generation of titanium hydride may also dominate, thereby inhibiting the dehydrogenation process.

[0015] Furthermore, the hydrogen mixture is a mixture of hydrogen and TiCl4 to better remove oxygen. In the present invention, the deoxygenation behavior of the dehydrogenation zone is manifested in two aspects. First, the titanium raw material after a hydrogenation releases hydrogen atoms in this area to directly react with the oxide layer on the surface of the powder, which can clean the surface of the particles and reduce the oxygen content. However, the degree of deoxygenation in this aspect is relatively low and far from meeting the demand. Based on this, the present invention optimizes the intake and selects a mixture of hydrogen and TiCl4 to further deoxygenate from the second aspect. Specifically analyzed: The reversible reaction in the dehydrogenation zone is shown in the following formula:

[0016]

[0017]

[0018] This process will generate a large amount of hydrogen atoms. Under the catalytic action of TiCl4, the hydrogen atoms will effectively combine with the oxygen in the powder so that the latter is discharged in the form of H2O, thereby significantly reducing the oxygen content in the powder. The specific reaction formula is:

[0019]

[0020] Preferably, the intake volume of TiCl4 accounts for 0.2-10% of the total volume of the mixed gas, and more preferably 0.5-5%. TiCl4 can promote the melting of active hydrogen. If the concentration of TiCl4 is too low, the catalytic deoxidation effect is poor, and if the concentration is too high, Cl - Impurities enter the material, reducing material performance and accelerating equipment corrosion.

[0021] Furthermore, the TiCl4 is heated to 130-160°C and then introduced into the rotary kiln, preferably 150-155°C.

[0022] Furthermore, the mixed gas flow rate is 1-20 L / min, preferably 1-10 L / min.

[0023] Furthermore, the mixed gas ensures that the pressure in the rotary kiln is 0.01-0.1MPa; the rotary kiln equipment cannot achieve too high a furnace pressure, but when the pressure is too low, not only a higher sintering temperature is required, but also the two hydrogenations cannot be completed well.

[0024] Furthermore, the temperature of the secondary hydrogenation zone is 450-650°C, preferably 480-600°C. In the dehydrogenation zone, the titanium hydride is only partially decomposed and deoxidized, and the secondary hydrogenation is performed at this time, and the reaction temperature and zone length and other conditions are controlled so that the x value satisfies 1.9≤x<2, preferably x is 1.924, so as to enhance the ease of crushing the titanium hydride powder. At the same time, the raw materials after the primary hydrogenation and dehydrogenation have been significantly refined under the action of grinding media, so the temperature in this zone does not need to be too high to avoid the decomposition of titanium hydride.

[0025] Furthermore, the length of the secondary hydrogenation zone accounts for 20-30% of the length of the rotary kiln heating zone; optional heating methods include resistance heating.

[0026] Furthermore, the low temperature cooling zone adopts forced cooling, and the temperature is lower than 50°C.

[0027] In a preferred embodiment, the rotary kiln also includes a preheating zone and at least two transition zones. The specific preparation method is: adding raw titanium to a continuous vacuum atmosphere rotary kiln, introducing hydrogen mixed gas until the pressure in the furnace is stable, and then the raw titanium passes through the preheating zone, the primary hydrogenation zone, the transition zone, the dehydrogenation zone, the transition zone, the secondary hydrogenation zone, and the low-temperature cooling zone in sequence, and finally is crushed and classified by air flow.

[0028] Furthermore, the temperature of the preheating zone is 600-750℃, and the length of the preheating zone accounts for 8-12% of the length of the rotary kiln heating zone. The preheating zone is in the rapid start-up stage of titanium hydrogenation. The temperature and length range match the activation energy of the titanium hydrogenation reaction. If the temperature is too low, the reaction will not start, and if it is too high, titanium will be sintered and the reaction will be too intense.

[0029] Preferably, the temperature of the preheating zone is 650-710° C., and a heating method such as induction heating may be used.

[0030] Furthermore, the temperature of the transition zone is 300-400° C., the transition zone separates the primary hydrogenation zone, the dehydrogenation zone and the secondary hydrogenation zone, and the length of the transition zone accounts for 10-20% of the length of the rotary kiln heating zone.

[0031] Furthermore, the preparation method also uses grinding media, and the raw titanium and grinding media are kept in a rotating grinding state after being fed into the rotary kiln. In-situ grinding and refinement are more conducive to the hydrogenation reaction of the raw materials, and the grinding media has a certain effect in absorbing the heat of the hydrogenation reaction, which can make the reaction more uniform and gentle.

[0032] Furthermore, the grinding medium has a polyhedral structure, including but not limited to at least one of regular and irregular polyhedrons such as triangular blocks, pentagonal stars, prisms, pyramids, etc. The maximum length of the grinding medium is 5-10 mm, and the material is selected from at least one of alloy steel, tungsten carbide, silicon nitride, and silicon carbide. The grinding medium with a polyhedral structure has edges and corners, which can grind titanium hydride more effectively, while the grinding medium with a spherical body can easily cause ball-material separation, resulting in poor grinding effect, and the present application should avoid the medium materials such as aluminum oxide and zirconium oxide to prevent the oxygen content in the material from increasing.

[0033] Furthermore, the mass ratio of raw titanium to grinding media is 1-5:1.

[0034] Furthermore, the operation time of the raw titanium in the primary hydrogenation zone is 2-5 h.

[0035] Furthermore, the D90 particle size of the non-stoichiometric titanium hydride powder is less than 20 μm, and the oxygen content is less than 1000 ppm.

[0036] Beneficial effects of the present invention:

[0037] (1) The synthesis route of the present invention includes two hydrogenation processes and one dehydrogenation process. By optimizing the hydrogenation and dehydrogenation temperatures and the zone length, the δ phase content and the hydrogenation amount of the hydrogenated titanium powder can be effectively increased by controlling the hydrogenation / dehydrogenation rate and degree, and the oxygen content inside the powder can be reduced to prepare a brittle, low-oxygen non-stoichiometric TiH 1.924 The powder is used to prepare titanium alloy products with excellent processing formability and mechanical properties.

[0038] (2) The present invention preferably uses a mixed gas of high-purity hydrogen and TiCl4 as the inlet gas, and adjusts process parameters such as the mixed gas flow rate and the amount of TiCl4 gas introduced to further reduce the oxygen content in the titanium hydride powder to below 1000 ppm.

[0039] (3) The present invention provides that the raw titanium is continuously rotated and ground in the rotary kiln, and the grinding medium parameters are specified, so as to better coordinate the temperature of the rotary kiln area for hydrogenation and dehydrogenation, and adjust the hydrogen-titanium stoichiometric ratio to 1.924.

[0040] (4) The preparation method of the present invention has continuous production capacity. Different outputs can be designed according to the size of the furnace body. Calculated based on a furnace with a diameter of 600 mm and a length of 12 m, the output per hour can reach 20-200 kg. Compared with an intermittent high-pressure furnace, the production efficiency is greatly improved and the production risk is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 : Flow chart corresponding to the preparation method of the present invention.

[0042] Figure 2 : TiH prepared in Example 1 of the present invention 1.924 XRD pattern of powder.

[0043] Figure 3 : TiH prepared in Example 1 of the present invention 1.924 SEM image of powder. DETAILED DESCRIPTION

[0044] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] The present embodiment provides a continuous preparation method of low-oxygen non-stoichiometric titanium hydride powder, specifically: the raw titanium and grinding media are mixed and transferred into a continuous vacuum atmosphere rotary kiln, the entire device is evacuated to 0.1 Pa, the oxygen content is reduced to 50 ppm, the heating is turned on, and after the temperature of each area reaches a predetermined value, the vacuum valve is closed. The hydrogen + TiCl4 mixed gas (mixing method: electrically heating TiCl4 at 150°C to form a gas, and mixing with high-purity hydrogen with a purity of >99.999%) valve is opened to allow air to enter, and the gas circulation device is turned on after the pressure in the furnace reaches 0.1 MPa to ensure that the pressure value in the furnace is stable; the rotation is turned on, and the raw titanium and grinding media are rotated in turn through the preheating zone, primary hydrogenation zone, transition zone, dehydrogenation zone, transition zone, secondary hydrogenation zone, and low-temperature cooling zone before entering a sealed storage tank, and finally airflow crushing and classification are carried out in an argon circulating airflow mill. For the process flow, see the attached Figure 1 .

[0047] The raw titanium is MHT-125 titanium sponge (oxygen content is 0.1%), with a particle size of 4 meshes; the grinding medium is tetrahedral, with a maximum length of 7 mm, and the material is selected from alloy steel; the mass ratio of raw titanium to grinding medium is 3:1; the operation time of raw titanium in the primary hydrogenation zone is 3 h. The mixed gas flow rate is 10 L / min, and the intake volume of TiCl4 accounts for 5% of the total volume of the mixed gas. The temperature of the preheating zone is 680℃, the heating method is induction heating, and the length accounts for 10% of the length of the rotary kiln heating area. The temperature of the primary hydrogenation zone is 600℃, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The temperature of the transition zone is 350℃, the heating method is resistance heating, and the length of each transition zone accounts for 15% of the length of the rotary kiln heating area. The temperature of the dehydrogenation zone is 750℃, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The temperature of the secondary hydrogenation zone is 540℃, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The low-temperature cooling zone uses external 25℃ water cooling.

[0048] Example 2

[0049] This embodiment provides a continuous preparation method of low-oxygen non-stoichiometric titanium hydride powder, specifically: after mixing the raw titanium and grinding media, transfer them into a continuous vacuum atmosphere rotary kiln, evacuate the entire device to 0.1 Pa, reduce the oxygen content to 50 ppm, start heating, and after the temperature of each area reaches a predetermined value, close the vacuum valve. Open the valve of the hydrogen + TiCl4 mixed gas (mixing method: electrically heat TiCl4 at 150°C to form gas, and mix with high-purity hydrogen with a purity of >99.999%) to inlet air, and after the pressure in the furnace reaches 0.1 MPa, open the gas circulation device to ensure that the pressure value in the furnace is stable; start rotation, and the raw titanium and grinding media rotate in turn through the preheating zone, the primary hydrogenation zone, the transition zone, the dehydrogenation zone, the transition zone, the secondary hydrogenation zone, and the low-temperature cooling zone, and then enter the sealed storage tank, and finally perform air flow crushing and classification in the argon circulating air flow mill.

[0050] The raw titanium is spherical titanium powder (oxygen content is 0.06%), D90 is 214 μm; the grinding medium is triangular block-shaped, with a maximum length of 5 mm, and is made of tungsten carbide; the mass ratio of raw titanium to grinding medium is 5:1; the operation time of raw titanium in the primary hydrogenation zone is 2 h. The mixed gas flow rate is 6 L / min, and the intake volume of TiCl4 accounts for 3% of the total volume of the mixed gas. The temperature of the preheating zone is 650°C, the heating method is induction heating, and the length accounts for 12% of the length of the rotary kiln heating zone. The temperature of the primary hydrogenation zone is 580°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating zone. The temperature of the transition zone is 330°C, the heating method is resistance heating, and the length of each transition zone accounts for 10% of the length of the rotary kiln heating zone. The temperature of the dehydrogenation zone is 720°C, the heating method is resistance heating, and the length accounts for 25% of the length of the rotary kiln heating zone. The temperature of the secondary hydrogenation zone is 480℃, the heating method is resistance heating, and the length accounts for 23% of the length of the rotary kiln heating area. The low-temperature cooling zone uses external 25℃ water cooling.

[0051] Example 3

[0052] This embodiment provides a continuous preparation method of low-oxygen non-stoichiometric titanium hydride powder, specifically: after mixing the raw titanium and grinding media, transfer them into a continuous vacuum atmosphere rotary kiln, evacuate the entire device to 0.1 Pa, reduce the oxygen content to 50 ppm, start heating, and after the temperature of each area reaches a predetermined value, close the vacuum valve. Open the valve of the hydrogen + TiCl4 mixed gas (mixing method: electrically heat TiCl4 at 150°C to form gas, and mix with high-purity hydrogen with a purity of >99.999%) to inlet air, and after the pressure in the furnace reaches 0.1 MPa, open the gas circulation device to ensure that the pressure value in the furnace is stable; start rotation, and the raw titanium and grinding media rotate in turn through the preheating zone, the primary hydrogenation zone, the transition zone, the dehydrogenation zone, the transition zone, the secondary hydrogenation zone, and the low-temperature cooling zone, and then enter the sealed storage tank, and finally perform air flow crushing and classification in the argon circulating air flow mill.

[0053] The raw titanium is titanium alloy chips (oxygen content is 0.2%), with a particle size of 5 meshes; the grinding medium is a five-pointed star shape with a maximum length of 10 mm and is made of silicon nitride; the mass ratio of raw titanium to grinding medium is 1:1; the operation time of raw titanium in the primary hydrogenation zone is 5 h. The mixed gas flow rate is 20 L / min, and the intake volume of TiCl4 accounts for 10% of the total volume of the mixed gas. The temperature of the preheating zone is 750°C, the heating method is induction heating, and the length accounts for 9% of the length of the rotary kiln heating area. The temperature of the primary hydrogenation zone is 650°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The temperature of the transition zone is 400°C, the heating method is resistance heating, and the length of each transition zone accounts for 18% of the length of the rotary kiln heating area. The temperature of the dehydrogenation zone is 850°C, the heating method is resistance heating, and the length accounts for 15% of the length of the rotary kiln heating area. The temperature of the secondary hydrogenation zone is 600℃, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The low-temperature cooling zone uses external 25℃ water cooling.

[0054] Comparative Example 1

[0055] It is basically the same as Example 1, except that the raw titanium and grinding media rotate in turn through the preheating zone, the primary hydrogenation zone, the transition zone, the secondary hydrogenation zone, and the low-temperature cooling zone before entering the sealed storage tank, and finally the air flow crushing and classification are carried out in the argon circulating air flow mill; the temperature of the preheating zone is 680°C, the heating method is induction heating, and the length accounts for 10% of the length of the rotary kiln heating zone. The temperature of the primary hydrogenation zone is 600°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating zone. The temperature of the transition zone is 350°C, the heating method is resistance heating, and the length of the transition zone accounts for 50% of the length of the rotary kiln heating zone. The temperature of the secondary hydrogenation zone is 540°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating zone.

[0056] Comparative Example 2

[0057] It is basically the same as Example 1, except that the temperature of the primary hydrogenation zone is 800°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The temperature of the transition zone is 350°C, the heating method is resistance heating, and the length of each transition zone accounts for 15% of the length of the rotary kiln heating area. The temperature of the dehydrogenation zone is 900°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area. The temperature of the secondary hydrogenation zone is 750°C, the heating method is resistance heating, and the length accounts for 20% of the length of the rotary kiln heating area.

[0058] Comparative Example 3

[0059] It is basically the same as Example 1, except that the temperature of the dehydrogenation zone is 750°C, the heating method is resistance heating, and the length accounts for 35% of the length of the rotary kiln heating area. The temperature of the secondary hydrogenation zone is 540°C, the heating method is resistance heating, and the length accounts for 5% of the length of the rotary kiln heating area.

[0060] Comparative Example 4

[0061] The method is basically the same as Example 1, except that the intake amount of TiCl4 accounts for 0.1% of the total volume of the mixed gas.

[0062] Comparative Example 5

[0063] It is basically the same as Example 1, except that the grinding medium is made of zirconium oxide.

[0064] Comparative Example 6

[0065] The method is basically the same as Example 1, except that the particle size of the raw titanium is 10 mm.

[0066] Comparative Example 7

[0067] The method is basically the same as Example 1, except that the raw material titanium is MHT-200, the oxygen content is 0.3%, and the particle size is 4 mesh.

[0068] Performance testing method:

[0069] 1. Hydrogen content and oxygen content: in accordance with GB / T 4698.7-2011 Chemical analysis method for titanium sponge, titanium and titanium alloys - determination of oxygen and nitrogen content, GB / T 4698.15-2011 Chemical analysis method for titanium sponge, titanium and titanium alloys - determination of hydrogen content;

[0070] 2. Particle size: tested using a laser particle size analyzer.

[0071] The performance test results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As attached Figure 2 The TiH prepared in Example 1 of the present application is shown. x The XRD pattern of the powder shows that the product is mainly pure TiH 1.924 phase, no other impurity peaks, no TiH 1.5 and TiH2 phases, and combined with the H content data in Table 1, it is calculated that non-stoichiometric TiH 1.924 Powder. AH 1.924 Titanium hydride powder is easy to crush and process. Figure 3The TiH prepared in Example 1 of the present application is shown. x The SEM image of the powder shows that the prepared TiH 1.924 The powder is irregular in shape, with a particle size D90 < 20 μm. The laser particle size test in Table 1 also shows that its D90 is 18.5 μm, which means that in this embodiment, the original millimeter-level titanium raw material undergoes two hydrogenations and one dehydrogenation, completely changing its initial morphology, and the obtained hydride particles show a uniform distribution at the micrometer scale. By testing the oxygen content, it can also be found that the oxygen content of the product is 631 ppm, and the product has a low oxygen content, which is suitable for subsequent high-purity titanium alloy preparation.

[0075] Through the preparation of Example 2 and Example 3, relatively pure TiH with a particle size D90 less than 20 μm can also be obtained. 1.924 powder, with an overall oxygen content of less than 1000 ppm.

[0076] As shown in Table 1, the dehydrogenation stage was removed in Comparative Example 1. Although it was hydrogenated twice, its oxygen content was as high as 1385ppm. Although TiCl4 was involved, there was no decomposition of TiH2, and the oxygen in the raw materials was difficult to remove, and it would even combine with part of the oxygen in the furnace, causing its oxygen content to increase instead of decrease. At the same time, direct two-step hydrogenation could not achieve the ideal hydrogenation effect. Although the structure of the raw materials was destroyed after one hydrogenation, there were still a lot of surfaces that were not exposed. The TiH2 structure formed on the surface layer hindered the further penetration of H, resulting in its H content being low. Correspondingly, its particle size was too large.

[0077] In Comparative Example 2, the use of higher hydrogenation and dehydrogenation temperatures caused the sintering of titanium, resulting in a D90 as high as 33.8 μm. At the same time, due to the high secondary dehydrogenation temperature, part of the TiH2 began to decompose again, so its H content was low. In Comparative Example 3, the reduction of the secondary hydrogenation time directly caused a decrease in the H content, forming TiH 1.5 , TiH 1.5 The metal property of the medium is stronger, which makes it difficult to crush, and the maximum D90 is 53.2μm. In Comparative Example 4, the insufficient TiCl4 content leads to poor deoxidation effect. In Comparative Example 5, the zirconium oxide grinding medium introduces a large amount of active oxygen, resulting in the oxygen content of the product as high as 6935ppm, becoming waste and unusable. In Comparative Example 6, if the initial titanium raw material is coarse, the particle size of the final product will be difficult to reduce, and the oxygen content will be difficult to control. In Comparative Example 7, if the initial titanium raw material has a high oxygen content, the deoxidation capacity of this scheme is insufficient, which ultimately leads to poor deoxidation effect.

[0078] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0079] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A continuous preparation method of low-oxygen non-stoichiometric titanium hydride powder, characterized in that: The raw titanium is added into the continuous vacuum atmosphere rotary kiln, and the hydrogen mixed gas is introduced until the pressure in the furnace is stable. The raw titanium passes through the primary hydrogenation zone, dehydrogenation zone, secondary hydrogenation zone, low temperature cooling zone in sequence, and finally is subjected to air flow crushing and classification; In titanium hydride TiHx powder, 1.9≤x<2; the hydrogen mixed gas is a mixed gas of hydrogen and TiCl4; the temperature of the primary hydrogenation zone is 500-700°C, the temperature of the dehydrogenation zone is 700-850°C, and the temperature of the secondary hydrogenation zone is 450-650°C; The oxygen content of the raw titanium does not exceed 0.2%, and the particle size is ≥ 5 mesh; The preparation method also uses grinding media. After the raw titanium and the grinding media are fed into the rotary kiln, they are kept in a rotating grinding state. The material of the grinding media is selected from at least one of alloy steel, tungsten carbide, silicon nitride, and silicon carbide.

2. The continuous preparation method according to claim 1, characterized in that: The raw titanium comprises at least one of sponge titanium, turned titanium chips, titanium alloy chips, spherical titanium powder, and spherical titanium alloy powder.

3. The continuous preparation method according to claim 1, characterized in that: The intake amount of TiCl4 accounts for 0.2-10% of the total volume of the mixed gas, and the mixed gas flow rate is 1-20L / min.

4. The continuous preparation method according to claim 1, characterized in that: The temperature of the primary hydrogenation zone is 550-650°C, and its length accounts for 20-30% of the length of the rotary kiln heating zone; the temperature of the dehydrogenation zone is 700-850°C, and its length accounts for 15-25% of the length of the rotary kiln heating zone; the temperature of the secondary hydrogenation zone is 480-600°C, and its length accounts for 20-30% of the length of the rotary kiln heating zone.

5. The continuous preparation method according to claim 1 or 4, characterized in that: The rotary kiln also includes a preheating zone and two transition zones. The specific preparation method is: adding raw titanium to a continuous vacuum atmosphere rotary kiln, adding hydrogen mixed gas until the pressure in the furnace is stable, and then the raw titanium passes through the preheating zone, the primary hydrogenation zone, the transition zone, the dehydrogenation zone, the transition zone, the secondary hydrogenation zone, and the low-temperature cooling zone in sequence, and finally is crushed and classified by air flow; The temperature of the preheating zone is 600-750℃, and the length of the preheating zone accounts for 8-12% of the length of the rotary kiln heating zone; The temperature of the transition zone is 300-400°C, and the length of the transition zone accounts for 10-20% of the length of the rotary kiln heating area; The mixed gas ensures that the pressure inside the rotary kiln is 0.01-0.1MPa.

6. The continuous preparation method according to claim 1, characterized in that: The grinding medium has a polyhedral structure, including at least one of a prism and a pyramid, and the maximum length of the grinding medium is 5-10 mm.

7. The continuous preparation method according to claim 6, characterized in that: The mass ratio of the raw titanium to the grinding medium is 1-5:

1.

8. The continuous preparation method according to claim 6, characterized in that: The operation time of the raw titanium in the primary hydrogenation zone is 2-5 hours.

9. The non-stoichiometric titanium hydride powder obtained by the continuous preparation method according to any one of claims 1 to 8, characterized in that: In the titanium hydride TiHx powder, x is 1.

924.

10. The titanium hydride powder according to claim 9, characterized in that The D90 particle size of the titanium hydride powder is less than 20 μm, and the oxygen content is less than 1000 ppm.

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