Thermochemical indirect deoxidation method for titanium powder or titanium alloy powder

Abstract

The invention provides a thermochemical indirect deoxidation method for titanium powder or titanium alloy powder, and particularly relates to the technical field of thermometallurgy. The thermochemical indirect deoxidation method for the titanium powder or the titanium alloy powder comprises the steps that the titanium powder or the titanium alloy powder is put into a titanium box to be sealed, and a sealed titanium bag is obtained; putting the sealed titanium bag, metal chlorate and rare earth metal into a titanium crucible to obtain a sealed titanium crucible; the closed titanium crucible, metal M and metal titanium are put into a stainless steel crucible to be sealed, and a closed stainless steel crucible is obtained; and the closed stainless steel crucible is heated and deoxidized, and the deoxidized titanium powder or titanium alloy powder is obtained in the titanium bag. According to the thermochemical indirect deoxidation method, impurities cannot be introduced in the deoxidation process, the oxygen content in the titanium powder or the titanium alloy powder can be effectively reduced, aftertreatment is simple, the process is simple, the production cost is low, and the product purity is high.

Description

Technical Field

[0001] The invention belongs to the technical field of pyrometallurgy, and in particular relates to a thermochemical indirect deoxidation method for titanium powder or titanium alloy powder. Background Art

[0002] With the development of science and technology, titanium products play a huge role in the military, aerospace, medical and civilian industries. Titanium powder and titanium alloy powder are important raw materials for the preparation of titanium parts, and their oxygen content affects the mechanical properties of titanium parts. Therefore, deoxidation of titanium powder and titanium alloy powder to reduce oxygen content has become a major research point.

[0003] At present, the common deoxidation methods of titanium powder or titanium alloy powder include hydrogen-assisted deoxidation, molten salt-assisted alkali metal thermochemical deoxidation, molten salt-assisted rare earth and rare earth chloride deoxidation, electrochemical deoxidation and calcium vapor deoxidation. In the hydrogen-assisted deoxidation method, hydrogen is easy to corrode titanium powder or titanium alloy powder. In the molten salt-assisted alkali metal thermochemical deoxidation, molten salt-assisted rare earth and rare earth chloride deoxidation methods, during the deoxidation process, alkali metal or rare earth metal and molten salt are easy to contaminate titanium powder and produce impurities. Although pickling or vacuum distillation can remove some impurities, it is impossible to maintain the purity of titanium powder or titanium alloy powder, and it will cause the oxygen content to increase again. Electrochemical deoxidation not only cannot achieve the true sintering of titanium powder, but the molten salt will also penetrate into the interior of the intermediate molded body, causing the molded body to be contaminated by the molten salt, and a large amount of wastewater will be generated. Calcium vapor deoxidation can obtain titanium powder with a low oxygen content, but calcium vapor directly acts on titanium powder, so that calcium impurities are introduced into titanium powder or titanium alloy powder, making post-treatment difficult. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for thermochemical indirect deoxidation of titanium powder or titanium alloy powder. The deoxidation method provided by the present invention does not introduce impurities during the deoxidation process, and can effectively reduce the oxygen content in the titanium powder or titanium alloy powder, with simple post-treatment, simple process, low production cost and high product purity.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a method for thermochemical indirect deoxidation of titanium powder or titanium alloy powder, comprising the following steps:

[0007] Putting titanium powder or titanium alloy powder into a titanium box and sealing it to obtain a sealed titanium package;

[0008] The sealed titanium bag, metal chloride and rare earth metal are placed into a titanium crucible to obtain a sealed titanium crucible;

[0009] The sealed titanium crucible, metal M and metal titanium are placed in a stainless steel crucible and sealed to obtain a sealed stainless steel crucible; the metal element in the metal chloride is the same as the metal M;

[0010] The sealed stainless steel crucible is heated and deoxidized to obtain deoxidized titanium powder or titanium alloy powder in a titanium bag; the heating and deoxidation temperature is higher than the melting point of the metal chloride and the melting point of the metal and lower than the melting point of titanium.

[0011] Preferably, after the heating and deoxidation is completed, the process further comprises opening the stainless steel crucible and the titanium crucible, performing vacuum distillation, and separating the titanium package.

[0012] Preferably, the step of loading the sealed titanium package, metal chloride and rare earth metal into a titanium crucible comprises:

[0013] After a portion of the metal chloride salt is loaded into the titanium crucible, a rare earth metal is laid on top, and then several sealed titanium bags are placed therein, with gaps between the sealed titanium bags. The remaining metal chloride salt is loaded into the titanium crucible to fill the gaps.

[0014] Preferably, the metal element and the metal M in the metal chloride salt include at least one of Ca, Mg, K and Na.

[0015] Preferably, the rare earth metal includes at least one of Y, Ho, La and Ce.

[0016] Preferably, the heating deoxidation time is 40 to 50 hours.

[0017] Preferably, the heating and deoxidation further includes natural cooling.

[0018] Preferably, the vacuum degree of the vacuum distillation is ≤200Pa;

[0019] The distillation temperature of the vacuum distillation is greater than or equal to the melting point of the metal chloride and lower than the melting point of titanium.

[0020] Preferably, the vacuum distillation further includes deoxygenation with an inert gas.

[0021] Preferably, the metallic titanium is sponge titanium.

[0022] The present invention provides a method for thermochemical indirect deoxidation of titanium powder or titanium alloy powder, comprising the following steps: putting titanium powder or titanium alloy powder into a titanium box and sealing it to obtain a sealed titanium bag; putting the sealed titanium bag, metal chloride and rare earth metal into a titanium crucible to obtain a closed titanium crucible; putting the closed titanium crucible, metal M and metal titanium into a stainless steel crucible and sealing it to obtain a closed stainless steel crucible; the metal element in the metal chloride is of the same type as the metal M; heating and deoxidizing the closed stainless steel crucible to obtain deoxidized titanium powder or titanium alloy powder in the titanium bag; the temperature of the heating and deoxidation is higher than the melting point of the metal chloride and the melting point of the metal and lower than the melting point of titanium. The deoxidation mechanism of the present invention is shown in Formulas 1 to 3:

[0023] MClx (l)+R(l)→RCl3(l)+M(l) Formula 1,

[0024] [O]+M(l)→cMO y (s) Formula 2,

[0025] MO y +RCl3(l)→MCl x (l)+ROCl(s) Formula 3,

[0026] The present invention utilizes metal chloride (MCl x ) and rare earth metals (R) during the heating process to generate metal M and RCl3, which increases the deoxidation limit and obtains titanium powder or titanium alloy powder with lower oxygen content. The generated metal M will combine with oxygen in the titanium powder or titanium alloy powder to obtain MO y , while RCl3 will capture MO y Generation of RaOCl and MCl x , lower MO y activity to improve the deoxidation limit; use a sealed titanium bag to separate titanium powder or titanium alloy powder from molten salt, and protect titanium powder or titanium alloy powder from pollution through indirect deoxidation, so that titanium powder or titanium alloy powder is not mixed with any impurities, and it is convenient for later separation without generating industrial waste; titanium and oxygen have a strong affinity, and the molten salt system will remove oxygen from the titanium foil used to prepare the titanium bag, resulting in a concentration difference between the oxygen content of titanium platinum and the oxygen content of titanium or titanium alloy powder. The oxygen in the high-concentration area will migrate to the low-concentration area. With continuous migration, the oxygen content of titanium or titanium alloy powder decreases, and the deoxidation of titanium or titanium alloy powder in a closed environment is achieved. The metal M and metal titanium in the closed stainless steel crucible can prevent the metal M generated in the closed titanium crucible from escaping outward, and the oxygen in the stainless steel crucible from transferring to the closed titanium crucible, which affects the deoxidation limit.

[0027] In addition, the ROCl generated after deoxidation can also be converted into RCl3 through treatment to increase the profit. The deoxidized titanium powder or titanium alloy powder obtained by the indirect thermochemical deoxidation method provided by the present invention has an oxygen content of less than 1500ppm. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0029] Figure 1 The present invention provides a schematic flow chart of the indirect thermochemical deoxidation method of titanium powder. DETAILED DESCRIPTION

[0030] The present invention provides a method for thermochemical indirect deoxidation of titanium powder or titanium alloy powder, comprising the following steps:

[0031] Putting titanium powder or titanium alloy powder into a titanium box and sealing it to obtain a sealed titanium package;

[0032] The sealed titanium bag, metal chloride and rare earth metal are placed into a titanium crucible to obtain a sealed titanium crucible;

[0033] The sealed titanium crucible, metal M and metal titanium are placed in a stainless steel crucible and sealed to obtain a sealed stainless steel crucible; the metal element in the metal chloride is the same as the metal M;

[0034] The sealed stainless steel crucible is heated and deoxidized to obtain deoxidized titanium powder or titanium alloy powder in a titanium bag; the heating and deoxidation temperature is higher than the melting point of the metal chloride and the melting point of the metal and lower than the melting point of titanium.

[0035] In the present invention, unless otherwise specified, the raw materials and equipment used are commercially available products well known in the art.

[0036] The invention puts titanium powder or titanium alloy powder into a titanium box and seals it to obtain a sealed titanium bag.

[0037] In the present invention, the oxygen content of the titanium powder or titanium alloy powder is preferably ≥1500 ppm.

[0038] In the present invention, the width of the sealed titanium bag is preferably 4-6 mm, the height is preferably 8-12 mm, and the length is preferably 45-55 mm. In a specific embodiment, the width of the sealed titanium bag is 5 mm, the height is 10 mm, and the length is 50 mm. The present invention controls the width of the sealed titanium bag to 5 mm to avoid too long heating and deoxidation time.

[0039] In the present invention, the titanium box is prepared from a titanium foil, and the thickness of the titanium foil is preferably 0.2 to 0.5 mm. In a specific embodiment, the thickness of the titanium foil can be 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0040] In the present invention, the step of packing the titanium powder or titanium alloy powder into the titanium box preferably includes: filling the titanium box with the titanium powder or titanium alloy powder.

[0041] The sealed titanium bag is obtained, and the sealed titanium bag, metal chloride and rare earth metal are loaded into a titanium crucible to obtain a closed titanium crucible.

[0042] In the present invention, the metal element in the metal chloride salt preferably includes at least one of Ca, Mg, K and Na.

[0043] In the present invention, the metal chloride salt is preferably dried before being loaded into the titanium crucible, and the drying step preferably includes drying the metal chloride salt at 200°C and 50 Pa for 12 hours, and then drying it at 400°C and 50 Pa for 12 hours. The present invention first removes free water at low temperature, and then removes bound water at high temperature to prevent the molten salt from being directly converted into oxides.

[0044] In the present invention, the rare earth metal preferably includes at least one of Y, Ho, La and Ce.

[0045] In the present invention, the step of loading the sealed titanium bag, the metal chloride and the rare earth metal into the titanium crucible preferably includes: after loading part of the metal chloride into the titanium crucible, laying the rare earth metal on top, and then placing a number of sealed titanium bags, with gaps between the sealed titanium bags, and loading the remaining metal chloride into the titanium crucible and filling the gaps. Specifically in the embodiment, after loading 1 / 5 of the mass of the metal chloride into the titanium crucible, laying the rare earth metal on top, and then placing a number of sealed titanium bags, with gaps between the sealed titanium bags, and loading the remaining mass of the metal chloride into the titanium crucible and filling the gaps.

[0046] In the present invention, metal chloride is filled in the interval of the titanium package, which is beneficial to uniform heating during heating and deoxidation, and the metal M obtained during the replacement reaction is evenly distributed around the sealed titanium package, ensuring the deoxidation efficiency.

[0047] In the present invention, the amount of the metal chloride salt is preferably such that: during heating and deoxidation, the metal chloride salt in a molten state can immerse the titanium package. During the heating and deoxidation process, the liquid molten salt completely immerses the titanium package to ensure deoxidation efficiency.

[0048] In the present invention, during the heating deoxidation process, the metal chloride and the rare earth metal undergo a replacement reaction, and the metal chloride participating in the replacement reaction preferably accounts for 10 to 100% of the mass of the total metal chloride. During the heating process, the replacement reaction is shown in Formula 1:

[0049] MCl x (l)+R(l)→RCl3(l)+M(l) Formula 1,

[0050] The molar amount of the metal chloride salt participating in the replacement reaction preferably accounts for 10-100% of the molar amount of the total metal chloride salt. In a specific embodiment, the molar amount of the metal chloride salt participating in the replacement reaction can account for 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% of the molar amount of the total metal chloride salt. x The replacement reaction produces RCl3, which can reduce production costs.

[0051] In the present invention, the RCl3 obtained by substitution and the MCl remaining after the substitution reaction are x The molar ratio of is preferably 2-3:2-3. In a specific embodiment, the RCl3 obtained by substitution and the MCl remaining after the substitution reaction are x The molar ratio of can be 2:3 or 3:2. In a specific embodiment of the present invention, when the rare earth metal R is Ce, the RCl3 obtained by substitution and the MCl remaining after the substitution reaction are x The molar ratio of is preferably 3:2; when the rare earth metal R is Y or Ho, the RCl3 obtained by substitution and the MCl remaining after the substitution reaction x The molar ratio of Y and Ho is preferably 2:3. The deoxidation capacity of Y and Ho is greater than that of Ce. The present invention controls the RCl3 obtained by substitution and the MCl remaining after the substitution reaction. x The molar ratio of 2-H2O to 2-H2O can achieve the lowest economic cost while maximizing the deoxygenation efficiency.

[0052] After obtaining the sealed titanium crucible, the present invention puts the sealed titanium crucible, metal M and metal titanium into a stainless steel crucible and seals the stainless steel crucible to obtain a sealed stainless steel crucible.

[0053] In the present invention, the metal element in the metal chloride is of the same type as the metal M, and the metal M preferably includes at least one of Ca, Mg, K and Na. In the present invention, the mass of the metal M is preferably 8 to 15 g / 500 mL (8 to 15 g of metal M for every 500 mL of the crucible chamber volume). In a specific embodiment, the mass of the metal M can be 8 g / 500 mL, 10 g / 500 mL, 12 g / 500 mL or 15 g / 500 mL. Metal M can suppress the volatilization of the metal in the metal chloride in the closed titanium crucible. Metal M forms metal vapor during the heating and deoxidation process, increasing the vapor partial pressure of the metal M in the stainless steel crucible chamber, thereby suppressing the continued volatilization of the metal M generated in the closed titanium crucible.

[0054] In the present invention, the mass of the metal titanium is preferably 15-25g / 500mL (15-25g of metal titanium for every 500mL of the crucible chamber volume). In a specific embodiment, the mass of the metal titanium can be 15g / 500mL, 18g / 500mL, 20g / 500mL, 22g / 500mL or 25g / 500mL. The metal titanium is preferably sponge titanium. Metal titanium can absorb oxygen in the chamber of the stainless steel crucible to ensure that the oxygen partial pressure inside the chamber is at an extremely low level, prevent the oxygen in the chamber from dissolving in the molten salt system and increasing the oxygen ion activity in the molten salt system, thereby increasing the deoxidation limit. Sponge titanium has a large specific surface area and a fast oxygen absorption rate.

[0055] After obtaining the sealed stainless steel crucible, the invention heats and deoxidizes the sealed stainless steel crucible to obtain deoxidized titanium powder or titanium alloy powder in a titanium bag.

[0056] In the present invention, the temperature of the heating deoxidation is preferably higher than the melting point of the metal chloride and the melting point of the metal and lower than the temperature of powder sintering. In a specific embodiment, the temperature of the heating deoxidation can be 700°C, 750°C, 800°C or 850°C; the time of the heating deoxidation is preferably 40 to 50 hours. In a specific embodiment, the time of the heating deoxidation can be 40 hours, 43 hours, 45 hours, 48 ​​hours or 50 hours. The deoxidation temperature is controlled at 700 to 850°C to avoid excessively high temperatures, which may cause sintering of titanium powder or titanium alloy powder, thereby affecting the mechanical properties of titanium powder or titanium alloy powder.

[0057] In the present invention, the deoxidation mechanism is shown in Formulas 2 and 3:

[0058] [O]+M(l)→cMO y (s) Formula 2,

[0059] MO y +RCl3(l)→MCl x (l)+ROCl(s) Formula 3,

[0060] RCl3(l) captures MO y Generate RaOCl(s), which can reduce MO y The activity of RCl3(l) can improve the deoxidation limit, so as to obtain titanium powder or titanium alloy powder with lower oxygen content. y Generating ROCl x and MCl x , ROCl x It will form a precipitate and sink to the bottom of the titanium crucible to avoid the formation of MO y It adheres to the outer surface of the closed titanium package, affecting the diffusion of oxygen in the later stage, resulting in reduced deoxidation efficiency. During the heating deoxidation process, because the deoxidizer has a stronger affinity with oxygen, the molten salt system will remove the oxygen of the titanium platinum used to prepare the titanium package, resulting in a concentration difference between the oxygen content of the titanium platinum and the oxygen content of the titanium or titanium alloy powder. The oxygen in the high-concentration area will migrate to the low-concentration area. With the continuous migration, the oxygen content of the titanium or titanium alloy powder decreases, achieving the deoxidation of the titanium or titanium alloy powder in a closed environment.

[0061] In the present invention, the heating and deoxidation preferably further includes natural cooling. Rapid cooling or water quenching will affect the mechanical properties of titanium powder.

[0062] In the present invention, after the heating deoxidation is completed, it is preferred to further include opening the stainless steel crucible and the titanium crucible, and subjecting the titanium crucible to vacuum distillation to separate the titanium package.

[0063] In the present invention, the vacuum distillation preferably further includes deoxygenation with an inert gas. Specifically, in the embodiment, the inert gas is used to remove oxygen in the vacuum furnace to prevent oxygen from contaminating the titanium powder or titanium alloy powder again. Titanium can still combine with oxygen at extremely low oxygen content, and oxygen in the vacuum furnace is removed to prevent oxygen from contaminating the titanium powder or titanium alloy powder again.

[0064] In the present invention, the vacuum degree of the vacuum distillation is preferably ≤200Pa. In a specific embodiment, the vacuum degree of the vacuum distillation can be 2Pa, 5Pa, 10Pa, 20Pa, 50Pa, 80Pa, 100Pa, 120Pa, 150Pa, 180Pa or 200Pa; the distillation temperature of the vacuum distillation is preferably greater than or equal to the melting point of the metal chloride and lower than the powder sintering temperature. In a specific embodiment, the distillation temperature of the vacuum distillation can be 700°C or 750°C. During the vacuum distillation process, the deoxidation system volatilizes, exposing the titanium bag, and the metal chloride and the titanium bag are separated. Control the distillation temperature, set the separation temperature above the melting point of the molten salt, and prevent the powder in the titanium bag from sintering; Control the vacuum degree to accelerate the volatilization of the metal chloride. The smaller the vacuum degree, the faster the molten salt volatilization rate.

[0065] In the present invention, the sealed titanium bag separated after the vacuum distillation is opened to obtain deoxidized titanium powder or titanium alloy powder.

[0066] The method provided by the present invention adopts an indirect deoxidation method to protect titanium powder or titanium alloy powder from molten salt contamination, and the post-processing is simple and the finished product can be easily separated. The oxygen content of the deoxidized titanium powder or titanium alloy powder is less than 1500ppm.

[0067] The schematic flow chart of the indirect thermochemical deoxidation method of titanium powder or titanium alloy powder provided by the present invention is as follows: Figure 1 shown.

[0068] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with specific embodiments below. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Any modification, equivalent replacement, improvement, etc. made to the implementation methods of the present invention based on the technical essence and general principles of the present invention without creative work should be within the scope of protection of the present invention.

[0069] Example 1

[0070] MgCl2 was dried at 200℃ and 50Pa for 12h, and then dried at 400℃ and 50Pa for 12h. After cooling to room temperature, it was taken out and bottled and placed in a glove box for later use. Metal cerium was cut into 5mm small pieces, vacuum-packed, and placed in a glove box for later use.

[0071] A titanium bag with a height of 4 mm, a width of 10 mm, and a length of 50 mm was filled with TC4 powder (oxygen content 4570 ppm, particle size <100 μm), sealed, and stored in a glove box for later use. The thickness of the titanium platinum sheet used to make the titanium bag was 0.3 mm.

[0072] Spread 1 / 5 of the mass of dried MgCl2 on the bottom of the titanium crucible, spread 145.70g of metal cerium on the dried MgCl2, put 8 titanium bags on the metal cerium, leave a space between each titanium bag, put the remaining dried MgCl2 into the titanium crucible, fill the reserved space, the total mass of dried MgCl2 added is 214.2g, and the molar ratio of the remaining MgCl2 after replacement to the replaced CeCl3 is 2:3. Cover the titanium cap of the titanium crucible and put it into a stainless steel crucible. Put 10g of metal Mg and 20g of sponge titanium on the outside of the titanium crucible in the stainless steel crucible, and weld the stainless steel crucible to seal.

[0073] Place a stainless steel crucible in a resistance furnace, heat it to 800°C and keep it for 48 hours. After natural cooling, open the stainless steel crucible and place it in a vacuum furnace that has previously used argon to remove oxygen from the furnace chamber. Perform vacuum distillation at 750°C at a vacuum degree of 10Pa until the molten salt is completely evaporated. After natural cooling, take out the titanium bag, take out the TC4 powder from the titanium bag, and vacuum package it for storage.

[0074] During the deoxidation process, metal cerium undergoes a substitution reaction with MgCl2 to generate the deoxidizer Mg. The reaction equation is as follows:

[0075] 2Ce(s)+3MgCl2(l)=2CeCl3(l)+3Mg(l) Formula 4;

[0076] The deoxygenation mechanism is as follows:

[0077] [O] 在TC4 +Mg(l)=MgO(s) Formula 5;

[0078] MgO(s)+CeCl3(l)=MgCl2(l)+CeOCl(s) Formula 6.

[0079] The oxygen content in the final TC4 powder was analyzed, and the results are shown in Table 1.

[0080] Table 1 Comparison of oxygen content in TC4 powder before and after deoxidation in Example 1

[0081]

[0082] As can be seen from Table 1, the deoxidation effect in Example 1 is better, the titanium alloy powder obtained reaches the expected target, and the oxygen content is below 1500 ppm.

[0083] Example 2

[0084] Place NaCl at 200℃ and 50Pa and dry for 12h, then place at 400℃ and 50Pa and dry for 12h, cool to room temperature, take out, bottle and place in a glove box for later use. Cut metal yttrium into 5mm small pieces, vacuum package and place in a glove box for later use.

[0085] A titanium bag with a height of 4 mm, a width of 10 mm, and a length of 50 mm was filled with Ti powder (oxygen content 3950 ppm, particle size <100 μm), sealed, and stored in a glove box for later use. The thickness of the titanium platinum sheet used to make the titanium bag was 0.3 mm.

[0086] Spread 1 / 5 of the mass of dried NaCl on the bottom of the titanium crucible, spread 66.68g of metal yttrium on the NaCl, put 8 titanium bags on the metal yttrium, reserve a gap between each titanium bag, put the remaining dried NaCl into the titanium crucible, fill the reserved gap, the total mass of dried NaCl added is 131.63g, and the molar ratio of the remaining NaCl after replacement to the YCl3 obtained by replacement is 3:2. Cover the titanium cap of the titanium crucible and put it into a stainless steel crucible. Put 10g of metal Na and 20g of sponge titanium on the outside of the titanium crucible in the stainless steel crucible, and weld the stainless steel crucible to seal.

[0087] Place a stainless steel crucible in a resistance furnace, heat it to 800°C and keep it for 48 hours. After natural cooling, open the stainless steel crucible and place it in a vacuum furnace that has previously used argon to remove oxygen from the furnace chamber. Perform vacuum distillation at 750°C at a vacuum degree of 10Pa until the molten salt is completely evaporated. After natural cooling, take out the titanium bag, take out the Ti powder from the titanium bag, and vacuum package it for storage.

[0088] During the deoxidation process, metal yttrium undergoes a replacement reaction with NaCl to generate the deoxidizer Na. The reaction equation is as follows:

[0089] Y(s)+3NaCl(l)=YCl3(l)+3Na(l) Formula 7;

[0090] The deoxygenation mechanism is as follows:

[0091] [O] 在Ti +2Na(l)=Na2O(s) Formula 8;

[0092] Na2O(s)+YCl3(l)=2NaCl(l)+YOCl(s) Formula 9.

[0093] The oxygen content in the Ti powder finally obtained was analyzed, and the results are shown in Table 2.

[0094] Table 2 Comparison of oxygen content in Ti powder before and after deoxidation in Example 2

[0095]

[0096]

[0097] As can be seen from Table 2, the deoxidation effect in Example 2 is better, the titanium powder obtained reaches the expected target, and the oxygen content is below 1500 ppm.

[0098] Example 3

[0099] Place MgCl2 at 200℃ and 50Pa and dry it for 12h, then place it at 400℃ and 50Pa and dry it for 12h, cool it to room temperature, take it out and bottle it, and place it in a glove box for later use. Cut the metal holmium into 5mm small pieces, vacuum seal it, and place it in a glove box for later use.

[0100] A titanium bag with a height of 4 mm, a width of 10 mm, and a length of 50 mm was filled with Ti-6Al-6V-2Sn powder (oxygen content 5210 ppm, particle size <100 μm), sealed, and stored in a glove box for later use. The thickness of the titanium platinum sheet used to make the titanium bag was 0.3 mm.

[0101] Place 1 / 5 of the mass of dried MgCl2 on the bottom of the titanium crucible, place 123.70g of metal holmium on the MgCl2, and place 8 titanium bags on the metal holmium, leaving a space between each titanium bag. Place the remaining dried MgCl2 in the titanium crucible to fill the reserved space. The total mass of dried MgCl2 added is 214.2g, and the molar ratio of the remaining MgCl2 after replacement to the replaced HoCl3 is 3:2. Cover the titanium cap of the titanium crucible and put it into a stainless steel crucible. Place 10g of metal Mg and 20g of sponge titanium on the outside of the titanium crucible in the stainless steel crucible, and weld the stainless steel crucible to seal.

[0102] Place a stainless steel crucible in a resistance furnace, heat it to 800°C and keep it for 48 hours. After natural cooling, open the stainless steel crucible and place it in a vacuum furnace that has previously used argon to remove oxygen from the furnace chamber. Perform vacuum distillation at 750°C at a vacuum degree of 10Pa until the molten salt is completely evaporated. After natural cooling, take out the titanium bag, take out the Ti-6Al-6V-2Sn powder from the titanium bag, and vacuum package it for storage.

[0103] During the deoxidation process, metal holmium undergoes a replacement reaction with MgCl2 to generate the deoxidizer Mg. The reaction equation is as follows:

[0104] 2Ho(s)+3MgCl2(l)=2HoCl3(l)+3Mg(l) Formula 10;

[0105] The deoxygenation mechanism is as follows:

[0106] [O] 在Ti-6Al-6V-2Sn+Mg(l)=MgO(s) Formula 11;

[0107] MgO(s)+HoCl3(l)=MgCl2(l)+HoOCl(s) Equation 12.

[0108] The oxygen content in the Ti-6Al-6V-2Sn powder finally obtained was analyzed, and the results are shown in Table 2.

[0109] Table 3 Comparison of oxygen content in Ti-6Al-6V-2Sn powder before and after deoxidation in Example 3

[0110]

[0111]

[0112] It can be seen from Table 3 that the deoxidation effect in Example 3 is better, and the titanium alloy powder obtained reaches the expected target, and the oxygen content is below 1500 ppm.

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for thermochemical indirect deoxidation of titanium powder or titanium alloy powder, characterized in that: The following steps are involved: Putting titanium powder or titanium alloy powder into a titanium box and sealing it to obtain a sealed titanium package; The sealed titanium bag, metal chloride and rare earth metal are placed into a titanium crucible to obtain a sealed titanium crucible; The sealed titanium crucible, metal M and metal titanium are placed in a stainless steel crucible and sealed to obtain a sealed stainless steel crucible; the metal element in the metal chloride is the same as the metal M; The sealed stainless steel crucible is heated and deoxidized to obtain deoxidized titanium powder or titanium alloy powder in a titanium bag; the heating and deoxidation temperature is higher than the melting point of the metal chloride and the melting point of the metal M and lower than the melting point of titanium.

2. The thermochemical indirect deoxidation method according to claim 1, characterized in that: After the heating and deoxidation is completed, the process further includes opening the stainless steel crucible and the titanium crucible, performing vacuum distillation, and separating the titanium package.

3. The thermochemical indirect deoxidation method according to claim 1, characterized in that: The step of placing the sealed titanium bag, metal chloride and rare earth metal into a titanium crucible comprises: After a portion of the metal chloride salt is loaded into the titanium crucible, a rare earth metal is laid on top, and then several sealed titanium bags are placed therein, with gaps between the sealed titanium bags. The remaining metal chloride salt is loaded into the titanium crucible to fill the gaps.

4. The thermochemical indirect deoxidation method according to claim 1, characterized in that: The metal element and the metal M in the metal chloride salt include at least one of Ca, Mg, K and Na.

5. The thermochemical indirect deoxidation method according to claim 1, characterized in that: The rare earth metal includes at least one of Y, Ho, La and Ce.

6. The thermochemical indirect deoxidation method according to claim 1, characterized in that: The heating deoxidation time is 40 to 50 hours.

7. The thermochemical indirect deoxidation method according to claim 1, characterized in that: The heating and deoxidation further includes natural cooling.

8. The thermochemical indirect deoxidation method according to claim 2, characterized in that: The vacuum degree of the vacuum distillation is ≤200Pa; The distillation temperature of the vacuum distillation is greater than or equal to the melting point of the metal chloride and lower than the melting point of titanium.

9. The thermochemical indirect deoxidation method according to claim 8, characterized in that: The vacuum distillation also includes deoxygenation with an inert gas.

10. The thermochemical indirect deoxidation method according to claim 1, characterized in that: The metallic titanium is sponge titanium.

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