JP2022515793A - Manufacturing method of titanium metal powder or titanium alloy powder - Google Patents

Abstract

The present invention relates to a method for producing a high-purity titanium metal powder or titanium alloy powder that can be used in various fields. The present invention comprises a step of partially reducing each of at least one metal oxide and titanium oxide, and mixing the partially reduced metal oxide and titanium oxide to obtain a first mixture. A step of producing, a step of mixing the first mixture and calcium hydride to produce a second mixture, and a step of completely reducing the second mixture to produce a titanium metal or a titanium alloy. A method for producing a titanium metal powder or a titanium alloy powder, including, achieves its purpose. [Selection diagram] Fig. 1

Description

The present invention relates to a method for producing a high-purity titanium metal powder or titanium alloy powder that can be used in various fields. Specifically, the present invention relates to a method for producing titanium metal powder or titanium alloy powder, which can be mass-produced and cost-reduced by utilizing a multi-step reduction step.

Titanium metals and titanium alloys are lightweight, have excellent mechanical properties, have excellent high temperature properties and corrosion resistance, and are suitable for medical, chemical, and aerospace fields where it is difficult to use other traditional iron-based alloys. It has been considered as a material. However, titanium-based materials have a problem that not only the raw materials are expensive but also the manufacturing cost is high.

Despite the excellent properties of titanium, due to the high cost problem, various manufacturing methods have been developed to reduce costs since the 1950s.

As a known method for producing titanium, a sponge titanium is produced using a Kroll process, and an ingot is produced using this by a VAR (Vacuum Arc Remelting) method, and the processed material is extruded or rolled. There is a way to make.

Currently, the Kroll process is most often used in the production of titanium metals, but the final product is in the form of a sponge rather than a powder. In the crawl process, a special electric furnace charges the pure titanium ore into a sponge form. This step, which is carried out in a chlorinator, forms titanium tetrachloride (TiCl ₄ ) in liquid form as the chlorine gas passes through the charge. The titanium tetrachloride formed in this way is purified through a complicated distillation process. After the distillation step, magnesium or sodium is added to the purified titanium tetrachloride and reacted to produce a metallic titanium sponge and magnesium or sodium chloride. Then, the titanium sponge is crushed and crimped. The crushed titanium sponge is melted by a vacuum arc remelting method (VAR). The crawl process has problems that the process is complicated, difficult to handle, and energy efficiency is not good.

Compared to ingot technology, powder metallurgy (PM) technology is attracting attention in that it can provide titanium with complex shapes at low cost without compromising mechanical properties. Using powder metallurgy (PM) technology has great potential in producing titanium at low cost, but the physical properties of titanium products produced in existing powder metallurgy processes are satisfactory. Not often used because it does not have the expected cost savings. Therefore, in order to produce titanium using powder metallurgy technology, not only cost reduction but also a method for improving the physical characteristics of the final product is required.

International Publication Patent WO2014 / 187867 discloses a wide range of methods for producing metal powders, metal alloy powders, intermetal compound powders and / or hydride powders thereof, but in order to reduce the metal powders to metals, hydrogen is used. Calcium hydride powders or granules are used, or calcium hydride is used directly in one or more metal oxides, with or without the presence of another metal, to produce metal alloy powders.

US Pat. No. 6,264,719 discloses a method for producing titanium alumina suspended in a small amount of aluminum oxide as a metal matrix composite powder when a small amount of titanium dioxide is reacted with an aluminum metal powder. There is.

Various methods for producing titanium metal powder or titanium alloy powder have been tried, but a method that can produce titanium metal powder or titanium alloy powder of excellent quality at low cost and can be mass-produced on an industrial scale. Is still required for development.

The present invention provides a titanium metal powder or titanium alloy powder that can produce high quality titanium metal powder or any type of titanium alloy powder at low cost and can be easily expanded and implemented on an industrial scale. It is intended to provide a method of manufacturing.

The above-mentioned problems are a) a step of partially reducing each of at least one metal oxide and a titanium oxide, and b) mixing the partially reduced metal oxide and the titanium oxide. The step of producing the first mixture, c) the step of mixing the first mixture with calcium hydride to produce the second mixture, and d) the step of completely reducing the second mixture to titanium. Achieved by methods of making titanium metal powders or titanium alloy powders, including the steps of making metals or titanium alloys.

The subjects of the present invention are a) a step of partially reducing any one of at least one metal oxide and a titanium oxide, and b) a metal oxidation in which any one of the above is partially reduced. The step of mixing the product with titanium oxide to produce a first mixture, c) the step of mixing the first mixture with calcium hydride to produce a second mixture, and d) the first. It is achieved by a method for producing a titanium metal powder or a titanium alloy powder, which comprises a step of completely reducing the mixture of 2 to produce a titanium metal or a titanium alloy.

Preferably, there is a step of partially reducing the first mixture between the steps b) and c).

Preferably, the partial reduction of the step a) and the complete reduction of the step d) are carried out by heat treatment at a temperature of 1,000 ° C to 1,500 ° C and a hydrogen atmosphere for 1 to 10 hours.

Further, preferably, the partial reduction in the step a) and the complete reduction in the step d) are performed by heat treatment at a temperature of 1,000 ° C to 1,500 ° C and a hydrogen atmosphere for 1 to 10 hours.

Preferably, the metal oxide is selected from the group consisting of _CaO , _V2O5 , _Cr2O3 , _{Nb2O5 , MoO3 , WO3 , Y2O3} and _ZrO2 .

Also preferably, the stoichiometric ratio of the first mixture to the calcium hydride is 1: 1.1-1.25.

Also preferably, the second mixture further comprises aluminum and vanadium oxide (V ₂ O ₅ ) powder.

Further, preferably, the titanium alloy powder is Ti-6Al-4V powder.

Further, preferably, the titanium metal powder and the titanium alloy powder have an oxygen content of less than 0.3% by weight and a particle size distribution of less than 50 μm.

The present invention can provide a low cost manufacturing method capable of producing excellent quality titanium metal powders and titanium alloy powders that can be used in more application fields. Through the present invention, the use of titanium and its alloy powders can be extended not only to general industrial applications but also to fields requiring excellent quality titanium metal powders such as aerospace, medical or munitions applications.

It is a scanning electron micrograph which shows the shape (Morphology) of the titanium metal powder produced by this invention. It is an X-ray diffraction pattern which shows the material phase of the titanium metal powder produced by this invention. It is a figure which shows the particle size distribution of the titanium metal powder produced by this invention. It is a scanning electron micrograph which shows the shape (Morphology) of the titanium alloy (Ti-6Al-4V) powder produced by this invention. It is a figure which shows the particle size distribution of the titanium alloy (Ti-6Al-4V) powder product produced by this invention.

All technical terms used in the present invention have the following definitions, as long as they are not specifically defined, and are consistent with the meanings generally understood by those skilled in the art in the art. In addition, although preferable methods and samples are described in the present specification, similar or equivalent methods are also included in the scope of the present invention.

The term'about'is 30, 25, 20, 15, 10, 9, 8, for a reference, quantity, level, value, number, frequency, percentage, dimension, size, quantity, weight or length. It means a quantity, level, value, number, frequency, percentage, dimension, size, quantity, weight or length that changes to about 7, 6, 5, 4, 3, 2 or 1%.

As used herein, the term "contains" includes the presented stage or component, or a group of stages or components, but not particularly necessary in the context, but any other stage or component, or stage. Or it must be understood as including the fact that the group of components is not excluded.

The method for producing a titanium metal powder or a titanium alloy powder of any form according to the present invention is characterized by including a multi-step reduction step. Preferably, it comprises two reduction steps. More preferably, it includes the following steps:

a) A step of partially reducing each of at least one metal oxide and a titanium oxide (first reduction step), and
b) The step of mixing the partially reduced metal oxide and the titanium oxide to produce a first mixture (first mixing step), and
c) A step of mixing the first mixture and calcium hydride to produce a second mixture (second mixing step), and
d) It comprises a step of heat-treating the second mixture to completely reduce it to produce a titanium metal or a titanium alloy (second reduction step).

According to one embodiment of the present invention, e) further includes a step of crushing and pulverizing the produced titanium metal or titanium alloy (powdering step).

Hereinafter, each step will be described in detail.

First, each of at least one metal oxide and titanium oxide is partially reduced (first reduction step).

The first reduction step is performed by heat-treating the metal oxide and the titanium oxide of the raw material materials at a temperature of 1,000 ° C. to 1,500 ° C. and a hydrogen atmosphere for 1 to 10 hours, respectively. The heat treatment temperature is preferably 1,100 ° C to 1,300 ° C, more preferably 1,100 ° C to 1,200 ° C. The treatment time is preferably 2 to 4 hours. The hydrogen atmosphere has a hydrogen gas flow of 1.5 l / min or more, preferably 1.5 l / min to 5 l / min, which varies depending on the size of the heat treatment furnace and the amount of the raw material.

In the first reduction step, a metal oxide or a titanium oxide is placed in a crucible having a semicircular cross section of a stainless steel material and heated in a heat treatment region of a furnace. As the heat treatment furnace, a tube furnace can be used. The heat treatment furnace used in the present invention has two separate heat treatment regions for the first reduction step and the second reduction step. Preferably, any type of heating furnace can be used that operates in a gas atmosphere capable of promoting a reduction reaction that operates at a temperature of 1,500 ° C. The heat treatment furnace must be suitable for work with gases such as hydrogen and argon.

Each heat treatment region can individually form a hydrogen gas flow.

In this stage, the heat treatment reduces the oxygen content of the metal oxide and titanium oxide of the raw material to form an oxide that can be easily reduced in the second reduction step.

The metal oxide is one or more selected from the group consisting of CaO, V ₂ O ₅ , Cr ₂ O ₃ , Nb ₂ O ₅ , MoO ₃ , WO ₃ , Y ₂ O ₃ and ZrO ₂ . CaO is preferred. The titanium oxide is TiO ₂ or TiO, more preferably TiO ₂ .

According to one embodiment of the present invention, when producing titanium alloy powder, the metal oxides are _CaO and _V2O5 , and aluminum or aluminum oxide can be used together with the metal oxide. In this case, the titanium alloy powder is Ti-6Al-4V.

The metal oxide and titanium oxide are preferably in powder form.

According to one embodiment of the present invention, the first reduction step is a1) a first partial reduction step of partially reducing each of calcium oxide and titanium oxide, and a2) the partial reduction. It comprises a second partial reduction step of partially reducing the first mixture of the calcium oxide and the titanium oxide mixed again.

By carrying out the first reduction step in two steps as described above, a mixture of calcium oxide and titanium oxide which is uniformly reduced and mixed can be obtained.

According to another embodiment of the present invention, only one of the metal oxide and the titanium oxide may be partially reduced in the first reduction step.

Next, the partially reduced metal oxide and the titanium oxide are mixed to prepare a first mixture (first mixing step), and the first mixture and calcium hydride are mixed. To produce a second mixture (second mixing step).

In this step, it is preferable to mix the first mixture with calcium hydride at a stoichiometric ratio of 1: 1.1 to 1.25.

The calcium hydrogen can be used in the form of powder or granule, and the particle size is preferably 0.02 to 2 mm. As the calcium hydride used in the present invention, a commercially available product can be used, but preferably, the calcium hydride used in the present invention is a calcium metal fragment (shaving) or a calcium metal granule (granule). ) Is a calcium hydride fragment or granule converted by heating in a hydrogen gas atmosphere at a temperature of 550 to 750 ° C. for 1 to 10 hours.

Next, it is a step (second reduction step) in which the second mixture is heat-treated and completely reduced to produce a titanium metal or a titanium alloy.

The heat treatment is performed at a temperature of 1,000 ° C to 1,500 ° C and a hydrogen atmosphere for 1 to 10 hours. The heat treatment temperature is preferably 1,100 ° C to 1,300 ° C, more preferably 1,100 ° C to 1,200 ° C. The treatment time is preferably 2 to 4 hours. The hydrogen atmosphere has a hydrogen gas flow of 1.5 l / min or more, preferably 1.5 l / min to 5 l / min, which varies depending on the size of the heat treatment furnace and the amount of the raw material. The heat treatment furnace used in the second reduction step is as described in the first reduction step.

At this stage, the partially reduced mixture of metal oxide and titanium oxide reacts with the reducing agent calcium hydride in a hydrogen atmosphere to form a titanium metal or a titanium alloy. The titanium metal or titanium alloy thus formed is recovered.

Finally, e) the powder produced in the recovery step is pulverized through the washing and drying steps. According to one embodiment of the invention, the recovered titanium metal or titanium alloy is in bulk form and can be ground using a high energy ball mill device prior to the cleaning and drying steps.

In the washing and drying steps, the crushed powder can be mixed with water to form a slurry, which can be washed while stirring. A solvent such as acetic acid can be added to the slurry to enhance the cleaning effect.

After washing, in the drying stage, the powder can be dried at a temperature of 80 to 90 ° C. in an open low temperature oven.

The titanium metal or titanium alloy produced in the present invention is in the form of powder, has a particle size distribution of 50 μm or less, preferably 10 to 50 μm, and an oxygen content of less than 0.3% by weight.

The term'powder'used in the present invention refers to particles having a particle size of less than 1 mm.

'X50' used in the present invention indicates the particle size distribution of the final powder, and indicates an intermediate diameter or an intermediate value of the particle size distribution. Preferably, X50 indicates a particle size distribution of 50 μm or less, or 40 μm or less, more preferably 20 μm or less.

Hereinafter, the present invention will be described in detail through examples, but these examples do not limit the scope of rights of the present invention.

The starting materials used in the examples of the present invention are shown in Table 1 below.

The apparatus used for analyzing the titanium metal powder and the titanium alloy powder finally produced in the present invention is shown in Table 2 below.

Example 1: Production of Titanium Metal Powder 50 g of CaO powder having a purity of 99.5% and 50 g of TiO ₂ powder having a purity of 99% are placed in a SUS310S crucible, respectively, and a hydrogen gas atmosphere of 2 to 3 L / min is placed in a heat-treated region of a tubular tube furnace. Underneath, it was partially reduced at 1100 ° C. for 2 hours. A second mixture was prepared by completely mixing 100 g of the first mixture of partially reduced CaO and TiO ₂ and 130 g of calcium hydride powder (particle size 0.02 to 2 mm). The stoichiometric ratio of calcium hydride to the first mixture is 1.1-1.25x. The second mixture was then placed in a SUS310S crucible and completely reduced at 1100 ° C. for 2 hours in a heat treated area of a tubular tube furnace under a hydrogen gas atmosphere of 2-3 L / min. The obtained bulk substance was placed in a ball mill device and pulverized, mixed with water and acetic acid, washed with stirring, and completely dried at 90 ° C. The physical characteristics of the metal powder were measured using the apparatus shown in Table 2. A scanning electron micrograph of the produced powder is shown in FIG. Further, in order to confirm the substance of the produced powder, the X-ray diffraction pattern was measured and shown in FIG. 2, and the particle size distribution of the powder was measured and shown in FIGS. 3 and 3. Looking at FIG. 2, it can be confirmed that the produced powder is a titanium (Ti) metal. Further, by looking at FIGS. 3 and 3, it can be confirmed that the particle size distribution range of the produced powder is 10 to 50 μm. Further, as a result of confirming the residual oxygen amount of the produced powder, it was 0.19 wt%. The residual oxygen content of the titanium metal powder produced by the present invention is significantly lower than that of the titanium metal powder produced by a known method.

Example 2: Production of Titanium Alloy (Ti-6Al-4V) Powder A mixture of 50 g of CaO powder having a purity of 99.5% and TiO ₂ powder having a purity of 99% was placed in a SUS310S pit, and a heat treatment region of a tubular tube furnace was placed. The mixture was partially reduced at 1100 ° C. for 2 hours under a hydrogen gas atmosphere of 2 to 3 L / min. A first mixture of partially reduced CaO and TiO ₂ , 7.13 g of 99.6% pure V ₂ O ₅ powder and 6 g of 99.5% pure aluminum metal powder, and calcium hydride powder (particle size). 207 g (0.02 to 2 mm) was completely mixed to prepare a second mixture. The stoichiometric ratio of calcium hydride to the first mixture is 1.1-1.25x. The second mixture was then placed in a SUS310S crucible and completely reduced at 1100 ° C. for 2 hours in a heat treated area of a tubular tube furnace under a hydrogen gas atmosphere of 2-3 L / min. The obtained bulk substance was placed in a ball mill device and pulverized, mixed with water and acetic acid, washed with stirring, and completely dried at 90 ° C. The physical characteristics of the metal powder were measured using the apparatus shown in Table 2. A scanning electron micrograph of the produced powder is shown in FIG. In addition, the particle size distribution of the produced powder was measured and shown in FIGS. 5 and 4. Further, by looking at FIGS. 5 and 4, it can be confirmed that the particle size distribution range of the produced powder is 10 to 50 μm. Further, as a result of confirming the residual oxygen amount of the produced powder, it was 0.28 wt%. The residual oxygen content of the titanium alloy powder produced by the present invention is significantly lower than that of the titanium alloy powder produced by a known method.

Example 3: Production of Titanium Alloy (Ti-6Al-4V) Powder 150 g of a mixture of CaO powder with a purity of 99.5% and TiO ₂ powder with a purity of 99% is placed in a SUS310S crucible and used in the heat treatment area of a tubular tube furnace. Partial reduction was carried out at 1100 ° C. for 2 hours under a hydrogen gas atmosphere of 2 to 3 L / min. A first mixture of partially reduced CaO and TiO ₂ , 7.13 g of 99.6% pure V ₂ O ₅ powder and 7.1 g of 99.5% pure aluminum oxide powder and calcium hydride powder ( A second mixture was prepared by thoroughly mixing 207 g (particle size 0.02 to 2 mm). The stoichiometric ratio of calcium hydride to the first mixture is 1.1-1.25x. The second mixture was then placed in a SUS310S crucible and completely reduced at 1100 ° C. for 2 hours in a heat treated area of a tubular tube furnace under a hydrogen gas atmosphere of 2-3 L / min. The obtained bulk material was placed in a ball mill device and pulverized, mixed with water and acetic acid, washed with stirring, and completely dried at 90 ° C. to obtain a titanium alloy (Ti-6Al-4V) powder. Obtained.

Although the specific parts of the present invention have been described in detail above, such a specific description is merely a desirable embodiment for a person having ordinary knowledge in the art, and the scope of the present invention is limited to this. It is clear that it is not limited. Therefore, it can be said that the substantial scope of the present invention is defined by the attached claims and their equivalents.

Claims (13)

a) Partial reduction of each of at least one metal oxide and titanium oxide, and
b) The step of mixing the partially reduced metal oxide and the titanium oxide to produce a first mixture, and
c) The step of mixing the first mixture and calcium hydride to produce a second mixture, and
d) A method for producing a titanium metal powder or a titanium alloy powder, comprising a step of completely reducing the second mixture to produce a titanium metal or a titanium alloy. a) Partial reduction of any one of at least one metal oxide and titanium oxide, and
b) A step of mixing a metal oxide obtained by partially reducing any one of the above and a titanium oxide to produce a first mixture, and
c) The step of mixing the first mixture and calcium hydride to produce a second mixture, and
d) A method for producing a titanium metal powder or a titanium alloy powder, comprising a step of completely reducing the second mixture to produce a titanium metal or a titanium alloy. The method for producing a titanium metal powder or a titanium alloy powder according to claim 1 or 2, which comprises a step of partially reducing the first mixture between the step b) and the step c). The partial reduction in the step a) and the complete reduction in the step d) are characterized by being heat-treated at a temperature of 1,000 ° C. to 1,500 ° C. and a hydrogen atmosphere for 1 to 10 hours. The method for producing a titanium metal powder or a titanium alloy powder according to claim 1 or 2. The partial reduction in the step a) and the complete reduction in the step d) are characterized by being heat-treated at a temperature of 1,000 ° C. to 1,500 ° C. and a hydrogen atmosphere for 1 to 10 hours. The method for producing a titanium metal powder or a titanium alloy powder according to claim 3. e) The method for producing a titanium metal powder or a titanium alloy powder according to claim 1 or 2, further comprising a step of crushing and pulverizing the produced titanium metal or titanium alloy. The metal oxide is claimed to be selected from the group consisting of CaO, V ₂ O ₅ , Cr ₂ O ₃ , Nb ₂ O ₅ , MoO ₃ , WO ₃ , Y ₂ O ₃ and ZrO ₂ . Item 2. The method for producing a titanium metal powder or a titanium alloy powder according to Item 1 or 2. The metal oxide is claimed to be selected from the group consisting of CaO, V ₂ O ₅ , Cr ₂ O ₃ , Nb ₂ O ₅ , MoO ₃ , WO ₃ , Y ₂ O ₃ and ZrO ₂ . Item 3. The method for producing a titanium metal powder or a titanium alloy powder according to Item 3. The titanium metal powder or titanium alloy powder according to claim 1 or 2, wherein the stoichiometric ratio of the first mixture to the calcium hydride is 1: 1.1 to 1.25. Manufacturing method. The method for producing a titanium metal powder or a titanium alloy powder according to claim 1 or 2, wherein the second mixture further contains aluminum and vanadium oxide (V ₂ O ₅ ) powder. The method for producing a titanium metal powder or a titanium alloy powder according to claim 10, wherein the titanium alloy is Ti-6Al-4V. The titanium metal powder or titanium alloy according to claim 1 or 2, wherein the titanium metal and the titanium alloy have an oxygen content of less than 0.3% by weight and a particle size distribution of less than 50 μm. How to make powder. A titanium metal powder or titanium alloy powder produced by the method according to claim 1 or 2, having an oxygen content of less than 0.3% by weight and a particle size distribution of less than 50 μm.

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