KR102630465B1 - Manufacturing method for Ti-alloy and Ti-alloy - Google Patents

Abstract

The present invention relates to a method for producing a titanium alloy and a titanium alloy. More specifically, the method for producing a titanium alloy of the present invention can stabilize the alloy metal in its elemental state and do not cause side reactions with the metal even during the subsequent debinding process. The mechanical strength and stability of titanium alloys manufactured by using a binder that is easily de-bound without stress can be improved to an excellent level. In addition, by using a binder with low structural distortion caused by temperature-induced stress and high strength, the shape stability and mechanical strength of the titanium alloy manufactured and the titanium material using the same can be significantly improved.

Description

Manufacturing method for titanium alloy and titanium alloy {Manufacturing method for Ti-alloy and Ti-alloy}

The present invention relates to a method for producing titanium alloy and titanium alloy.

Titanium (Ti) and titanium alloys exhibit low density, high specific strength, biocompatibility, and excellent corrosion resistance, making them ideal materials for biomedical and aerospace applications such as orthopedics or dental implants. It is receiving a lot of attention. The corrosion resistance and biocompatibility of titanium materials are believed to be due to titanium oxide (TiO ₂ ) naturally occurring on the titanium surface.

However, pure titanium has limited application to various artificial biological implants such as hip joints, pins, and screws due to its low wear resistance compared to stainless steel and Co-Cr alloy. In addition, it has been found that fractures in pure titanium cause inflammation and pain in the body.

There have been attempts to manufacture titanium alloys by adding various alloying elements to improve the mechanical properties of titanium. For example, titanium alloy-based Ti-6Al-4V (TAV) showed high strength. However, these titanium alloys release toxic vanadium as wear fragments, and the corrosion resistance, wear resistance, and biocompatibility are lowered compared to pure titanium.

As another titanium alloy, a nickel-titanium based shape corporate alloy incorporating nickel was synthesized. Although it had improved mechanical properties and corrosion resistance compared to nickel, it still showed low biocompatibility due to allergic and carcinogenic effects caused by nickel.

Therefore, it is important to manufacture a titanium alloy that is biocompatible and exhibits an appropriate level of mechanical properties using non-toxic or mildly toxic elements.

Meanwhile, conventional metal processing technologies such as metal casting, CNC machining, and forming result in a waste of a lot of metal during cutting and finishing processes to develop final products, resulting in a waste of processing costs for titanium alloy. In this regard, powder metallurgy, including powder or metal injection molding (PIM/MIM), and 3D printing hold great promise for developing near-net shaped titanium-based materials of desired shapes and sizes in a cost-effective manner. presents.

3D printing processes can vary based on working principles such as metal extrusion, binder jetting, etc., similar to FDM (Fused Deposition Modeling). Therefore, binder selection according to the method adopted for final product development is a very important factor. Basically, a binder should have some unique features for different technologies. For example, in the case of MIM, the binder is a major component (usually a wax) that wets the powder particles and maintains the required fluidity and provides sufficient handling strength (green) to the injection molded sample even after removal of the major component through solvent or thermal bonding. It consists of two components: a secondary component (usually a high molecular weight polymer), also called a backbone component, to provide strength.

Although various thermoplastic polymers have been attempted to be extruded into metal, temperature-induced stresses in thermoplastic polymers (distortions associated with relaxation of the polymer structure) can deteriorate the appearance of 3D printed products with layered structures.

In this regard, various semi-crystalline amorphous polymers such as PMMA, PP, PS, PEEK, etc. have been attempted to overcome the processing problems associated with thermoplastics, but many of these polymers have the limitation of being inherently brittle.

Accordingly, the present inventors have found that by using any one or more binders of polyvinylpyrrolidone (PVP), polyvinylbutyral (PVB), and polyvinyl alcohol (PVA), titanium alloy metal can be stabilized in the elemental state, and the metal The present invention was completed by discovering that it can be easily debound without side reactions and that the shape stability and mechanical strength of the final product can be improved even during processing such as metal powder injection molding, 3D printing, and powder metallurgy. It came down to this.

Patent Document 1. Korean Patent No. 10-2128736

The present invention was created to solve the problems described above, and the purpose of the present invention is to provide a binder that can stabilize the alloy metal in its elemental state and can be easily debound without side reactions with the metal during the subsequent debinding process. The object of the present invention is to provide a method of manufacturing a titanium alloy using the method and a titanium alloy that can improve biocompatibility and stability while maintaining mechanical strength.

One aspect of the present invention includes (i) preparing an alloy metal mixture by mixing titanium, niobium, and tin; (ii) preparing a polymer binder solution by dissolving at least one polymer binder among polyvinylpyrrolidone (PVP), polyvinylbutyral (PVB), and polyvinyl alcohol (PVA) in a solvent; (iii) preparing a mixture by mixing the alloy metal mixture and the polymer binder solution; (iv) drying the mixture; and (v) removing the polymer binder from the mixture.

Another aspect of the present invention provides a titanium alloy manufactured by the above titanium alloy manufacturing method.

Another aspect of the present invention provides a titanium alloy processed product manufactured by processing the titanium alloy by any one or more of metal powder injection (MIM) molding, 3D printing, and powder metallurgy (P/M).

The present invention relates to a method for producing a titanium alloy and a titanium alloy. The method for producing a titanium alloy of the present invention can stabilize the alloy metal in its elemental state, and can be easily removed without causing side reactions with the metal during the subsequent debinding process. The mechanical strength and stability of titanium alloy manufactured using a binding binder can be improved to an excellent level. In addition, by using a binder with high strength and little structural distortion due to temperature-induced stress, the shape stability and mechanical strength of the final product can be improved during processing such as metal powder injection molding, 3D printing, and powder metallurgy.

Figure 1 is a schematic diagram schematically showing the bonding characteristics between polyvinylpyrrolidone and an alloy metal mixture according to an embodiment of the present invention.
Figure 2 is a schematic diagram schematically showing the manufacturing process of the manufacturing example of the present invention.
Figure 3 is a schematic diagram schematically showing the manufacturing process of Example 1 of the present invention.
Figure 4 is a schematic diagram schematically showing the debinding device used to remove the binder in Example 1 of the present invention.
Figure 5 is (a) an optical microscope image of the PVP-alloy metal mixture of Preparation Examples 1-1 to 1-4 of the present invention and the alloy metal mixture of Comparative Preparation Example 1, (b) a photo of the fluidity measurement through tissue paper. Images (c,d) show the results of fluidity measurement.
Figure 6 shows scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) images of the PVP-alloy metal mixture prepared in Example 1 of the present invention.
Figure 7 is a graph showing the actual alloy composition ratio and the expected alloy composition ratio based on EDS analysis results of the PVP-alloy metal mixture prepared in Example 1 of the present invention.
Figure 8 shows thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results of PVP (K 90).
Figure 9 shows a scanning electron microscope (SEM) image after removal of the polymer binder at 600°C in Example 1 of the present invention.
Figure 10 shows a scanning electron microscope (SEM) image of Example 2 of the present invention at 1000°C after removal of the polymer binder.
Figure 11 is a graph showing carbon content according to binder removal temperature.
Figure 12 shows the results of X-ray diffraction analysis (XRD) after 30 days of preparing the PVP-alloy metal mixture of Examples 1 to 2 of the present invention.

Hereinafter, the present invention will be described in more detail with the accompanying drawings and examples.

The present invention includes the steps of (i) mixing titanium, niobium and tin to prepare an alloy metal mixture; (ii) preparing a polymer binder solution by dissolving at least one polymer binder among polyvinylpyrrolidone (PVP), polyvinylbutyral (PVB), and polyvinyl alcohol (PVA) in a solvent; (iii) preparing a mixture by mixing the alloy metal mixture and the polymer binder solution; (iv) drying the mixture; and (v) removing the polymer binder from the mixture.

Hereinafter, each step of the titanium alloy manufacturing method of the present invention will be described in more detail.

(i) mixing titanium, niobium and tin to prepare an alloy metal mixture

First, the metal components of the alloy are mixed to produce an alloy metal mixture.

The alloy metal mixture may include 40 to 83% by weight of titanium, 5 to 20% by weight of niobium, and 2 to 10% by weight of tin.

Zirconium belongs to the titanium group (IV B) and can be a promising titanium alloy element with chemical properties similar to titanium. In addition, zirconium, similar to titanium, forms an oxide film on the surface, improving corrosion resistance and being non-toxic. It exhibits two types of crystal structures: bcc (β) at high temperatures and hcp (α) at low temperatures. The alloy metal mixture may further include zirconium, and there is an advantage in that corrosion resistance performance is improved when zirconium is further included. The zirconium content of the alloy metal may be 10 to 40% by weight.

The alloy metal mixture may preferably include 40 to 83% by weight of titanium, 10 to 40% by weight of zirconium, 5 to 20% by weight of niobium, and 2 to 10% by weight of tin, and more preferably 43 to 10% by weight of titanium. It may contain 60% by weight, 23 to 35% by weight of zirconium, 13 to 17% by weight of niobium, and 4.3 to 7% by weight of tin, and most preferably, the alloy metal mixture contains 47 to 55% by weight of titanium, and 25 to 25% by weight of zirconium. It may contain 30% by weight, 14 to 16% by weight of niobium, and 4.5 to 6% by weight of tin.

Titanium (Ti) is known as a material with low density, high specific strength, biocompatibility, and excellent corrosion resistance. If the titanium content in the alloy metal mixture is less than 40% by weight, strength may be reduced, and conversely, if it is more than 83% by weight, wear resistance may be reduced.

If the content of niobium (Nb) in the alloy metal mixture is less than 5% by weight, biocompatibility may be lowered or a brittle ω phase may appear in the final manufactured alloy, and conversely, if it is more than 20% by weight, strength may be reduced.

If the content of tin (Sn) in the alloy metal mixture is less than 2% by weight, the wear resistance and fatigue resistance of the titanium alloy may be reduced, and conversely, if the content of tin (Sn) is more than 10% by weight, the stability of the -β phase may be reduced.

If the zirconium (Zr) content in the alloy metal mixture is less than 10% by weight, corrosion prevention performance may be reduced, and conversely, if it is more than 40% by weight, strength may be reduced.

(ii) preparing a polymer binder solution by dissolving at least one polymer binder among polyvinylpyrrolidone (PVP), polyvinylbutyral (PVB), and polyvinyl alcohol (PVA) in a solvent.

Next, prepare a polymer binder solution.

The solvent may be any one or more of water, ethanol, methanol, propanol, and butanol.

As described above, in methods of manufacturing near-net-shaped alloy materials such as conventional MIM processes or 3D printing, the binders used conventionally do not take into account the different degrees of interaction depending on the alloy components. In addition, some polymer binders were not biocompatible at all (PMMA), and the use of thermoplastic or semi-crystalline amorphous polymers had the problem of deforming the shape of the final product (distortion, defects) or making it brittle due to temperature-induced stress. did.

Accordingly, in the present invention, the alloy metal is stabilized in the elemental state by using any one or more binders of polyvinylpyrrolidone (PVP), polyvinyl butyral (PVB), and polyvinyl alcohol (PVA). In the binder removal process, the shape stability and strength of the manufactured titanium alloy and titanium alloy processed products using the same were significantly improved by easily removing the binder without any side reactions with the metal.

In particular, when the polymer binder is polyvinylpyrrolidone (PVP), it can be easily dissolved in non-toxic solvents such as water and alcohol, and will not cause an inflammatory reaction in the body even if a trace amount remains after the binder removal process. You can. In addition, there is an advantage in that titanium alloy can be stabilized even when it contains zirconium, which is highly reactive with oxygen and moisture, and the possibility of ignition can be significantly reduced.

Figure 1 is a schematic diagram schematically showing the bonding characteristics between polyvinylpyrrolidone and an alloy metal mixture according to an embodiment of the present invention. Referring to FIG. 1, polyvinylpyrrolidone (PVP) is a metal (i.e., nd) through non-covalent interaction between the oxygen (O) non-bonding electrons of polyvinylpyrrolidone and the empty d-orbital (i.e., nd) of the metal. In particular, it promotes the stabilization of highly reactive zirconium (Zr) and is coated on the metal surface. As a result, the bonding and coating of PVP on the metal surface forms an assembly where smaller particles (i.e. Zr, Nb and Sn) are attached to larger particles (i.e. Ti).

In particular, the polymer binder may be polyvinylpyrrolidone with a K value of 15 to 100, preferably 50 to 95. If the K value of polyvinylpyrrolidone is less than the lower limit, fluidity may deteriorate and processability may be reduced. On the other hand, if it exceeds the above upper limit, it takes a long time to dissolve it in the solvent, which may increase the process time.

The K value is a measure of molecular weight and can be obtained from viscosity measurement using Fikentscher's formula. More specifically, it can be measured using a 1% by weight aqueous solution according to the method described in the literature (H. Fikentscher, Cellulose-Chemie, 1932, 13:58-64/71-74).

The polymer binder solution may contain the polymer binder at a concentration of 0.01 to 65 mg/mL, preferably 0.03 to 10 mg/mL. When the concentration of the polymer binder satisfies the above range, the alloy metal components well formed single particles, so metal dust did not occur, and it was confirmed that the composition deviation depending on the location was reduced.

(iii) preparing a mixture by mixing the alloy metal mixture and the polymer binder solution.

Next, the alloy metal mixture and the polymer binder solution are mixed to bind the alloy metal components with the polymer binder to fix the alloy elements.

At this time, the polymer binder is used in an amount of 0.1 to 30 parts by weight, preferably 0.4 to 25 parts by weight, more preferably 5 to 23 parts by weight, and most preferably 10 to 22 parts by weight, based on 100 parts by weight of the metal mixture. The alloy metal mixture may be mixed with the polymer binder solution. If the weight part of the polymer binder relative to 100 parts by weight of the metal mixture is less than the lower limit, the components of the alloy metal mixture may not form a single particle. Conversely, if it exceeds the upper limit, the binder may remain or may be undesirable even after the binding removal process. By-products may be generated.

(iv) drying the mixture

The mixture is then dried to remove the previously used solvent.

The drying may be performed at 30 to 100°C for 1 to 12 hours, preferably at 40 to 90°C for 2 to 8 hours, and more preferably at 50 to 80°C for 4 to 7 hours.

If at least one of the drying temperature and drying time is less than the lower limit, solvent may remain and pores, etc. may occur. Conversely, if it exceeds the upper limit, a cooling process is required again and the overall process time may be excessively long, which is preferable. don't do it

(v) removing the polymer binder from the mixture.

The binder is then removed from the mixture to prepare the alloy.

Step (v) may be performed by dissolving the mixture in a polar solvent. At this time, the polar solvent may be one or more of water or ethanol, but is not limited thereto. In particular, the polymer binder used in the present invention is highly soluble in polar solvents and can be removed by dissolving the mixture in a polar solvent.

Step (v) may be performed by applying heat to the mixture. In the case of conventionally used thermoplastic or semi-crystalline polymer binders, distortion or defects may occur when finally manufactured due to temperature-induced stress, but the polymer binder used in the present invention does not cause distortion or defects even when heat is applied, resulting in final manufacturing. The dimensional stability of the manufactured material can be improved.

More specifically, step (v) may be performed by raising the temperature of the mixture to 500 to 1300 ° C and maintaining it for 0.5 to 10 hours, more preferably by heating the mixture to 800 to 1100 ° C and maintaining it for 0.8 hours. It may be performed by maintaining it for up to 6 hours.

At this time, if any one of the temperature and time is less than the lower limit, the binder is not sufficiently removed and the remaining binder may deteriorate the physical properties of the titanium alloy. Conversely, if it exceeds the upper limit, the physical properties of the titanium alloy produced by a side reaction of titanium This may decrease significantly.

After step (v), the mixture from which the polymer binder has been removed can be washed with a solvent or subjected to an air-blowing process to remove trace amounts of remaining carbon.

Steps (i) to (v) may be performed under an inert atmosphere. Zirconium is highly reactive with oxygen and moisture in the atmosphere, so if steps (i) to (v) above are not performed under an inert atmosphere, there is a possibility of fire. The inert atmosphere may mean an argon atmosphere.

(vi) Processing the titanium alloy obtained in step (v) to obtain a titanium alloy processed product.

Next, the titanium alloy obtained in step (v) can be processed to obtain a titanium alloy processed product.

At this time, the processing may be one or more of a metal powder injection molding (MIM) molding process, 3D printing, and powder metallurgy (P/M).

The titanium alloy manufacturing method of the present invention uses a polymer binder with low brittleness and little change in structure depending on temperature, and the final product is manufactured even during processing such as metal powder injection molding, 3D printing, and powder metallurgy. Shape stability and mechanical strength can be improved.

In particular, although not explicitly described in the following examples and comparative examples, in the titanium alloy manufacturing method of the present invention, titanium alloy was manufactured by varying the following conditions.

As a result, the mechanical strength, biocompatibility, and dimensional stability of the titanium alloy manufactured only when all of the following conditions were satisfied were uniformly excellent.

However, when any of the following conditions were not satisfied, it was confirmed that mechanical strength and biocompatibility were not uniformly excellent or dimensional stability was reduced, leading to a significant decrease in durability and processability.

The alloy metal mixture includes 47 to 55% by weight of titanium, 25 to 30% by weight of zirconium, 14 to 16% by weight of niobium, and 4.5 to 6% by weight of tin,

The solvent is ethanol,

The polymer binder is polyvinylpyrrolidone (PVP) with a K value of 50 to 95,

The polymer binder solution contains the polymer binder at a concentration of 0.03 to 10 mg/mL,

Step (iii) is mixing the alloy metal mixture and the polymer binder solution so that the polymer binder is 10 to 22 parts by weight based on 100 parts by weight of the metal mixture,

The drying is carried out at 50 to 80 ° C. for 4 to 7 hours,

Step (v) is performed by raising the temperature of the mixture to 800 to 1100 ° C and maintaining it for 0.8 to 6 hours,

Steps (i) to (v) may be performed under an inert atmosphere.

Additionally, the present invention provides a titanium alloy manufactured by the above titanium alloy manufacturing method.

In addition, the present invention provides a titanium alloy processed product manufactured by processing the titanium alloy by any one or more of metal powder injection (MIM) molding, 3D printing, and powder metallurgy (P/M).

The titanium alloy manufactured by the titanium alloy manufacturing method has very little dust and exhibits excellent mechanical properties, so it can be applied to industrial materials and parts. It also shows excellent biocompatibility, including titanium, and can be applied to medical materials and parts.

Hereinafter, preferred embodiments are presented to aid understanding of the present invention. However, the following examples are merely illustrative of the present invention, and it is clear to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the attached patent claims.

Example

ingredient

Titanium (Ti), niobium (Nb), and tin (Sn) powders with a purity of more than 99% were purchased from Thermo Fisher Scientific in Korea, and the average sizes of the titanium, niobium, and tin powders were ~149 μm (100 mesh) and 1~149 μm (100 mesh), respectively. 5 μm and ~44 μm. Zirconium (Zr) with a size of ~149 μm (100 mesh) was purchased from Sigma Aldrich, South Korea.

The Zr powder was prepared by ball milling (ball size-10 mm, ball-to-powder ratio (BPR) 5:1, milling speed 120 rpm) in a glove box for 100 hours to reduce the size to 1-15 μm.

Polyvinylpyrrolidone (PVP, Sokalan K 17 and K 90 P) was purchased from BASF, Korea, and ethanol was purchased from Daejung, Korea.

Production Example 1-1. Ti-8Nb-2Sn

Figure 2 is a schematic diagram schematically showing the manufacturing process of the manufacturing example of the present invention. The manufacturing process of Preparation Example 1-1 will be described below with reference to Figure 2.

Alloy metal mixture manufacturing

82.23% by weight of titanium, 13.62% by weight of niobium, and 4.15% by weight of tin (Ti:Nb:Sn=90:8:2 atomic ratio) were placed in a glove box and mixed by ball milling without balls at 100 rpm for 4 hours in air. An alloy metal mixture was prepared by doing so.

PVP-alloy metal mixture manufacturing

After preparing a PVP solution in which polyvinylpyrrolidone (PVP, K 90) was dissolved in ethanol to a concentration of 60 mg/mL, the alloy was added to 0.25 parts by weight of polyvinylpyrrolidone based on 100 parts by weight of the alloy rapid mixture. The metal mixture was added to the PVP solution and stirred for 15 minutes to prepare the mixture. The mixture was then dried at 60°C for 6 hours and then pulverized (using a motor and pestle).

Manufacturing Example 1-2

It was prepared in the same manner as Preparation Example 1-1, but the alloy metal mixture was added to the PVP solution so that 0.5 parts by weight of polyvinylpyrrolidone was added to 100 parts by weight of the rapid alloy mixture.

Manufacturing Example 1-3

It was prepared in the same manner as Preparation Example 1-1, except that the alloy metal mixture was added to the PVP solution so that 0.75 parts by weight of polyvinylpyrrolidone was added to 100 parts by weight of the rapid alloy mixture.

Manufacturing Example 1-4

It was prepared in the same manner as in Preparation Example 1-2, except that polyvinylpyrrolidone (PVP, K 17) was used instead of polyvinylpyrrolidone (PVP, K 90).

Comparative Manufacturing Example 1

An alloy metal mixture was prepared and used in the same manner as in Example 1.

Example 1. Ti-20Zr-11Nb-3Sn

Figure 3 is a schematic diagram schematically showing the manufacturing process of Example 1 of the present invention. The manufacturing process of Example 1 will be described below with reference to Figure 3.

alloy metal mixture

50.89% by weight of titanium, 28.04% by weight of zirconium, 15.81% by weight of niobium, and 5.26% by weight of tin (Ti:Zr:Nb:Sn=66:20:11:3 atomic ratio) were placed in a glove box, and the ball was placed under an inert atmosphere. An alloy metal mixture was prepared by mixing through tumbling and ball milling at 100 rpm for 4 hours.

PVP-alloy metal mixture

A PVP solution (0.06 mg/mL) was prepared by mixing 12 mg of polyvinylpyrrolidone (PVP, K 90) in 200 mL of ethanol and then degassed for 2 hours under an argon gas atmosphere. Next, 60 mg (100 parts by weight) of the rapid alloy mixture and the PVP solution (20 parts by weight of PVP) were mixed under an inert atmosphere and stirred for 3 hours to prepare a mixture. The mixture was then dried at 60°C for 6 hours under an inert (argon) atmosphere and then pulverized (using a motor and pestle).

Debinding

Figure 4 is a schematic diagram schematically showing the debinding device used to remove the binder in Example 1 of the present invention.

The dried mixture was heated to 600°C at a temperature increase rate of 0.5°C/min under an inert atmosphere (Ar) gas using the debinding device shown in FIG. 4 and maintained for 1 hour to perform thermal debinding.

Example 2

The same procedure as in Example 1 was performed, except that the alloy metal mixture was heated to 1000°C at a rate of 0.5°C/min under an inert atmosphere (Ar) gas and then maintained for 1 hour to perform thermal debinding.

Experimental Example 1. Liquidity measurement results

To confirm the binding efficacy of the binder to the metal powder particles, a fluidity test was performed on the alloy metal mixtures of Preparation Examples 1-1 to 1-4 and Comparative Preparation Example 1 using tissue paper and a flow meter JIS-Z-2502. This was performed and the results are shown in Figure 5.

Figure 5 is (a) an optical microscope image of the PVP-alloy metal mixture of Preparation Examples 1-1 to 1-4 of the present invention and the alloy metal mixture of Comparative Preparation Example 1, (b) a photo of the fluidity measurement through tissue paper. Images (c,d) show the results of fluidity measurement.

Referring to FIG. 5(a), it can be seen that the particle size increased more when the binder was added than when the binder was not added, and the particle size increased as the concentration increased.

Referring to FIG. 5(b), it can be seen that the metal dust remaining on the surface of the tissue paper decreases when the binder is added.

Referring to FIG. 5(c), it can be seen that compared to Comparative Preparation Example 1 in which the binder was not added, Preparation Examples 1-1 to 1-3 in which the binder was added could flow freely without significant change in flow rate.

Referring to FIG. 5(d), the flow rate increases in Preparation Example 1-4 compared to Preparation Example 1-2. As the molecular weight of the polymer binder (PVP) used decreases, the flow rate increases and fluidity decreases. You can see that it happens.

Experimental Example 2. Morphological analysis

To investigate the binding efficacy of PVP, the morphology of the binder-added alloy metal mixture was examined by digital optical microscopy (DIM-03, Alfa Mirage Co., Ltd., Japan) and scanning electron microscopy (SEM) (Thermo Fisher Scientific, Apero 2S). ) was confirmed using and is shown in Figure 6.

Figure 6 shows scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) images of the PVP-alloy metal mixture prepared in Example 1 of the present invention. Referring to the EDS analysis results and color mapping image of FIG. 6, the formation of a single particle containing all alloy elements can be confirmed. Titanium, zirconium, niobium, and tin belong to different groups and periods of the periodic table, so single particle alloy metals containing them can be expected to exhibit changes in properties. In addition, since the PVP-metal interaction varies depending on the type of metal and the density of the metal is also different, different alloy metals bound through PVP can form various phases. In addition, some parts of the alloy (Figure 6(b)) had slight differences in composition, and some parts (Figure 6(c)) had the same composition, and there were slight differences in composition depending on the part of the alloy. This phenomenon is due to the difference in the density of various metals and the degree of interaction between PVP, and the small size of alloy metals covers relatively large size metals (e.g. titanium), obscuring these larger metals during EDS analysis. This may be the result. In addition, the EDS analysis image showed that the C-spectrum existed continuously, confirming that the alloy metal surface was well coated with the PVP binder.

The alloy metal composition ratio of the PVP bonded alloy obtained through SEM images and EDS analysis results and the alloy metal composition ratio expected when manufacturing the alloy are shown in Figure 7.

Figure 7 is a graph showing the actual alloy composition ratio and the expected alloy composition ratio based on EDS analysis results of the PVP-alloy metal mixture prepared in Example 1 of the present invention. Referring to FIG. 7, it can be seen that compared to the expected alloy metal composition ratio, niobium and tin were maintained at similar levels, but the content of zirconium increased and the content of titanium decreased.

Experimental Example 3. Thermal property analysis

In order to consider the debinding temperature, the thermal properties of the binder (PVP, K 90) used in the above example were measured using DSC (differential scanning calorimetry, DSC Q20, TA Instruments) and thermogravimetric analysis (TGA) ((Q500, TA Instruments Co., Ltd) and shown in Figure 8.

Figure 8 shows thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results of PVP (K 90). Referring to FIG. 8, it can be seen that PVP decomposes before heat treatment at 500°C.

Figure 9 shows a scanning electron microscope (SEM) image after removal of the polymer binder at 600°C in Example 1 of the present invention.

One of the essential properties of a binder is that the binder easily debinds before the temperature at which the metal reacts with the binder. The starting temperatures for oxidation and nitridation of titanium are reported to be ~680 ℃ and ~850 ℃, respectively. PVP binder contains oxygen and nitrogen, so when oxidation or nitridation of titanium occurs, impurities in the alloy accumulate and the properties of the alloy deteriorate. can deteriorate.

In Figure 9(b), it can be seen that zirconium and niobium, along with trace amounts of residual binder, exist in the form of plant roots, which is probably due to simultaneous inter- or intra-diffusion. . According to previous reports, it is known that inter- or intra-diffusion occurs at a high temperature of about 600°C, but the alloy metal mixture of Example 1 contains a large amount of polymer binder present at the interface of the two alloy elements. It was found that the spread was hindered by this. The diffusion process is a step before alloy formation, and since the self- and inter-diffusion processes are different depending on the type of metal, the composition of the final alloy element produced may change compared to the expected composition.

Referring to the EDS analysis of Figures 9(b-c), it can be seen that the concentrations of metals, especially titanium and zirconium, are different compared to the expected alloy composition ratio. On the other hand, c-content appeared to be decreased. More specifically, a continuous carbonaceous layer (c-chain) as shown in FIG. 6 was not observed, and rather, it can be seen that carbon exists in a particle-like form. Referring to FIG. 8, it was expected that the polymer would decompose before 500°C, but c-content existed due to the formation of carbon particles and strong interaction between the carbon particles and the metal. In this case, the catalytic effect of the transition metal may have contributed to the formation of functional c-particles that exhibit strong interaction with the metal.

Figure 10 shows a scanning electron microscope (SEM) image after removal of the polymer binder at 1000°C in Example 2 of the present invention. Referring to FIG. 10, the composition ratio of the alloy debound at 1000°C was different compared to the alloy debound at 600°C and the PVP-alloy metal mixture, and the carbon content was further reduced. This is because the diffusion characteristics and phase behavior of the alloy components are different. Neck formation indicates that as the temperature increases further, the alloy components will sinter to form the final titanium alloy. The exact carbon content according to binder removal temperature is shown in Figure 11.

Experimental Example 4. XRD analysis

To confirm the stability of the metal powder in the elemental state after PVP bonding and the changes after debonding, X-ray diffraction (XRD) analysis was performed using an X-ray diffractometer (XRD, Bruker D2 Fraser) at a CuKα radiation source.

Figure 12 shows the results of X-ray diffraction analysis (XRD) after 30 days of preparing the PVP-alloy metal mixture of Examples 1 to 2 of the present invention.

Referring to FIG. 12, the alloy components containing highly reactive titanium and zirconium are bound by PVP and the elemental state is stable even after 30 days, confirming that PVP stabilizes the alloy metal in the elemental state. .

Claims (15)

(i) mixing titanium, niobium, tin and zirconium to prepare an alloy metal mixture;
(ii) preparing a polymer binder solution by dissolving polyvinylpyrrolidone (PVP), a polymer binder, in a solvent;
(iii) preparing a mixture by mixing the alloy metal mixture and the polymer binder solution;
(iv) drying the mixture; and
(v) removing the polymer binder from the mixture,
The polymer binder is polyvinylpyrrolidone with a K value of 15 to 100,
A method of producing a titanium alloy, characterized in that the drying is performed at 30 to 100 ° C. for 1 to 12 hours. The method of producing a titanium alloy according to claim 1, wherein the alloy metal mixture includes 40 to 83% by weight of titanium, 5 to 20% by weight of niobium, and 2 to 10% by weight of tin. The method of producing a titanium alloy according to claim 2, wherein the alloy metal mixture further contains 10 to 40% by weight of zirconium. The method of claim 1, wherein the alloy metal mixture includes 47 to 55% by weight of titanium, 25 to 30% by weight of zirconium, 14 to 16% by weight of niobium, and 4.5 to 6% by weight of tin. . The method of claim 1, wherein the solvent is one or more of water, ethanol, methanol, propanol, and butanol. delete The method of claim 1, wherein the polymer binder solution contains 0.01 to 65 mg/mL of the polymer binder. The method of claim 1, wherein in step (iii), the polymer binder is mixed in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the metal mixture. delete The method of claim 1, wherein step (v) is performed by dissolving the mixture in a polar solvent. The method of claim 1, wherein step (v) is performed by heating the mixture to a temperature of 500 to 1300° C. and maintaining it for 0.5 to 10 hours. The method of claim 1, wherein steps (i) to (v) are performed under an inert atmosphere. According to paragraph 1,
The alloy metal mixture includes 47 to 55% by weight of titanium, 25 to 30% by weight of zirconium, 14 to 16% by weight of niobium, and 4.5 to 6% by weight of tin,
The solvent is ethanol,
The polymer binder is polyvinylpyrrolidone (PVP) with a K value of 50 to 95,
The polymer binder solution contains the polymer binder at a concentration of 0.03 to 10 mg/mL,
Step (iii) is mixing the alloy metal mixture and the polymer binder solution so that the polymer binder is 10 to 22 parts by weight based on 100 parts by weight of the metal mixture,
The drying is carried out at 50 to 80 ° C. for 4 to 7 hours,
Step (v) is performed by raising the temperature of the mixture to 800 to 1100 ° C and maintaining it for 0.8 to 6 hours,
A method for producing a titanium alloy, characterized in that steps (i) to (v) are performed under an inert atmosphere. A titanium alloy prepared according to any one of claims 1 to 5, 7 to 8, and 10 to 13. A titanium alloy processed product manufactured by processing the titanium alloy of claim 14 by any one or more of metal powder injection (MIM) molding, 3D printing, and powder metallurgy (P/M).