WO2010050715A2 - Ultra-light metal carbide-metal nanostructured material and method for preparing the same - Google Patents

Abstract

The present invention relates to a method for preparing an ultra-light metal carbide-metal nanostructured material, wherein metal carbide is nanopulverized, mixed with metal binder powder, and then while electrically-generated heat is applied, a pressure forming and sintering process may be performed in a short period. The present invention enables the manufacture of an ultra-light metal carbide-metal nanostructured material that effectively suppresses growth of crystalline particles and also exhibits relatively superior mechanical properties.

Description

Nanostructured metal carbide-metal carbide materials and methods of manufacturing the same

The present invention relates to a method for producing a metal carbide-metal carbide material. More specifically, the present invention relates to a method of manufacturing a nanostructured metal carbide-metal carbide material.

Metal carbide-metal carbide materials are prepared by mixing metal carbide powder as a binder, usually as a composite, and metal powder as a binder, followed by press molding and sintering. At this time, a hot pressing machine, a hot isostatic pressing machine, and the like are used. As the above cemented carbide material, representatively, WC-Co-based, TiC-Co-based, etc. are known, but are widely used in the technical field requiring excellent hardness and fracture toughness at room temperature and high temperature. In the case of the metal carbide-metal cemented carbide material described above, hardness and wear resistance generally increase when the particle size of the metal carbide decreases, while hardness and wear resistance decrease, but fracture toughness increases as the amount of the metal binder increases.

Conventionally known metal carbide-metal carbide materials, in particular WC-Co-based cemented carbide materials, vary depending on the particle size and the amount of metal binder, but typically, the powders of WC and Co are heated by vacuum heating, hot compression molding machines or hot After being introduced into a hydrostatic molding machine, it is manufactured by heating at a high temperature of about 1400 ° C. or more (for 1 hour or more) for a long time (sintering and pressure sintering). However, it is economically unfavorable in that it manufactures over high temperature and long time. In particular, when the metal carbide powder is heated at a high temperature for a long time and sintered under pressure and atmospheric pressure, crystal grains of the metal carbide grow, and thus the size of the metal carbide particles in the cemented carbide material increases, thereby increasing the mechanical properties (hardness characteristics, etc.). Will adversely affect. On the other hand, manufacturing methods such as the method of using a water-soluble salt (Korean Patent No. 374705) or growing a specific surface of a crystal first (Korean Patent Publication No. 1999-69647) are known, but they are not satisfactory in simplicity and the like.

In order to alleviate the problems caused by long time sintering at high temperature, Korean Patent No. 424780 and Journal of Korean Powder Metallurgy Institute, Vol. 8, No. 4, 2001 describes a method for producing WC-Co cemented carbide in a short time using a field-activated pressure-assisted combustion synthesis by milling W, C and Co uniformly. Suggesting. However, the patent is difficult to obtain a cemented carbide material of the nanostructure because the growth of crystal grains due to heat generation occurs in the process of forming a compound of metal and carbon through heating.

In addition, recently, a method of mixing and milling a metal carbide and a metal binder together, followed by sintering within a short time, is known, but due to the presence of a ductile metal binder powder, it is difficult to effectively nanopowder the metal carbide. In fact, the grain size of the cemented carbide material produced in this way is about 400 nm or more.

The method provided according to the embodiment of the present invention is nano-powdered metal carbide to nano-sized particle size, mixed with the metal binder powder, and then press molding and sintering process in a short time while applying the heat generated by the current Do this. As a result, it is possible to manufacture a metal carbide-metal carbide material having a nano structure that effectively suppresses the growth of grains and exhibits relatively excellent mechanical properties.

Method for producing a metal carbide-metal carbide material of nanostructures provided according to one embodiment of the present invention,

a) nanopowdering the metal carbide;

b) mixing the metal binder powder with the nano powder of the metal carbide;

c) press molding and sintering by applying heat generated by a current to the mixed powder; And

d) cooling the press-formed and sintered product;

It includes.

Step c) is preferably carried out until there is no change in shrinkage length of the product being press-molded and sintered. Specifically, if there is no change in shrinkage length, the current is cut off and the press-molded and sintered product until just before the current interruption. Perform the cooling step. In step d) the press-formed and sintered product is typically cooled to room temperature.

According to the present invention, as the metal carbide, for example, from titanium carbide (TiC), tungsten carbide (WC), silicon carbide (SiC), tantalum carbide (TaC), vanadium carbide (VC), niobium carbide (NbC) and the like 1 or 2 or more can be selected and used.

In step a), the metal carbide can be nanopowdered by milling (particularly ball milling), where "nano powder" is used herein to mean a nano-sized particle size (ie nanostructure), preferably about It can be understood to have an average particle size of 100 nm or less.

In the step b), as the metal binder powder, for example, one or two or more may be selected from iron (Fe), nickel (Ni), cobalt (Co), and the like. Since the hardness decreases as the amount of the metal binder powder increases, but fracture toughness may increase, the amount of the metal binder powder added is preferably based on the total mixed powder (i.e., nano powder and metal binder powder of metal carbide). The amount is adjusted to about 1 to 50% by volume.

According to the present invention, the press forming and sintering process of step c) may be carried out typically within a short time of about 5 minutes, even within about 2 minutes. In this case, the heat generated by the current may be, for example, heat by induction current or heat by pulse current. When using heat by induction current, it is preferable to use an induction current having a frequency of about 1 to 100 Hz. On the other hand, when heat by pulse current is used, a pulse current having a period of preferably about 1 mA to about 1 mA can be used.

Pressing may be carried out preferably at a pressure of about 10 to 1000 MPa, more preferably about 40 to 200 MPa, and the heating rate upon sintering is preferably about 100 to 5000 ° C / min, more preferably Can be adjusted to about 100 to 1000 ° C / min. In addition, the press molding and sintering process may be performed under a pressure (vacuum) condition of about 0.01 to 1 Torr.

On the other hand, for example, a linear variable differential transformer (LVDT) may be used to observe the change in shrinkage length of the press-formed and sintered products.

In the method of manufacturing a nanostructured metal carbide-metal carbide material according to the present invention, first nanopowder the metal carbide to have a nano-sized particle size (i.e., have a nanostructure) and mix it with the metal binder powder. Pressing and sintering can be performed within a short time (for example, within 5 minutes). As a result, it is possible to suppress or limit grain growth of metal carbides as compared with the prior art, and to manufacture metal carbide-metal carbide materials having nanostructures with excellent mechanical properties. The present invention is expected to be commercialized in various technical fields such as cutting tools, wear and impact resistant tools, high temperature and high pressure parts, and mold materials.

1 is a diagram showing a schematic configuration of an induction current heating / pressurizing sintering apparatus that can be used for producing a nanostructured metal carbide-metal carbide material according to a preferred embodiment of the present invention;

2 is a schematic illustration of a die assembly of a pulsed current heating / pressurizing sintering apparatus usable for producing nanostructured metal carbide-metal carbide materials according to a preferred embodiment of the present invention;

3 is a graph showing changes in temperature (□) and shrinkage displacement (■ ▲ ◆) according to heating time during high frequency induction current heating / pressurizing sintering in Example 1;

4 is a scanning electron microscope (SEM) photograph of each of (a) TiC-10 vol.% Fe, (b) TiC-10 vol.% Co, and (c) TiC-10 vol.% Ni, prepared according to Example 1; ego; And

FIG. 5 is a graph showing XRD patterns of (a) TiC-10 vol.% Fe, (b) TiC-10 vol.% Ni, and (c) TiC-10 vol.% Co, prepared according to Example 1. FIG.

The present invention can be achieved by the following description with reference to the accompanying drawings. It is to be understood that the following description describes preferred embodiments of the present invention, and the present invention is not necessarily limited thereto.

In the present invention, the term "nanostructure" is not a concept that is strictly interpreted, but may mean a structure in which the size of the unit structure (ie, grain) is preferably about 100 nm or less. Materials having such nanostructures can be differentiated and exhibit a variety of functions compared to conventional micrometer level materials.

Nanostructured metal carbide-metal carbide materials according to embodiments of the invention are prepared as follows:

First, the metal carbide is nanopowdered to have a nano-sized particle size.

Examples of the metal carbide include titanium carbide (TiC), tungsten carbide (WC), silicon carbide (SiC), tantalum carbide (TaC), vanadium carbide (VC), niobium carbide (NbC), and the like. You can select more than two. The metal carbide is preferably in powder form, the particle size of which may vary depending on the type of metal carbide, but is typically about 1 to 50 ㎛ level is appropriate.

By nano-powdering the metal carbide as described above, it is possible to facilitate the formation of the metal carbide-metal carbide material having a nano structure and to increase the sintering speed. In this case, the nanopowder preferably has a particle size of about 100 nm or less, in particular about 60 nm or less.

According to an embodiment of the present invention, in order to nanopowder the metal carbide, various grinding methods can be applied, preferably milling, in particular ball milling. Unlike the other milling methods, the ball milling method can apply sufficiently large energy and is suitable for nanopowdering metal carbides.

Examples of such ball milling methods include vibrating ball milling, attrition ball milling, high energy ball milling, and the like, and high energy ball milling is particularly preferable. At this time, stainless balls, zirconia balls, alumina balls, carbide balls, etc. may be used, but it is preferable to use a carbide ball that can minimize the mixing of impurities in the milling process. The size of the ball used for ball milling is preferably in the range of about 1 to 20 mm, and the weight ratio (ball / powder) of the ball to the powder (powder) is preferably in the range of about 1: 1 to 30: 1. Further, the milling speed is preferably about 100 to 500 rpm, more preferably about 200 to 250 rpm, and the milling temperature is appropriate at room temperature. The above-described milling conditions are understood by way of example, and the present invention is not necessarily limited thereto.

According to the present invention, the metal carbide is nanopowdered, and then metal binder powder is added and mixed thereto.

As described above, examples of the metal binder component include cobalt, iron, nickel, and the like, and one or two or more may be selected and used therefrom. In this case, when the size of the metal binder powder is too small, the tendency to oxidize increases, whereas when too large, the metal binder powder may not be suitable for uniform mixing with the metal carbide. Thus, metal binder powders, preferably in the range of about 0.5 to 50 μm, can be used. The metal binder powder may be added in an amount corresponding to about 1 to 50% by volume, based on the total mixed powder (ie, nanopowder of metal carbide and metal binder powder).

The method of mixing the metal carbide nanopowder and the metal binder powder can be carried out using a method known in the art without particular limitation, and it is preferable to mix as uniformly as possible. For this purpose, for example, a universal milling machine or the like can be used.

When the mixing of the metal carbide nanopowder and the metal binder powder is completed, pressure forming and sintering are performed, and heat generated by current (external current) is used. Specifically, heat and pressure generated by, for example, induced current or pulse current are applied, and through this press forming and sintering process, metal carbide-metal carbide (composite) of nano structure is applied. The material is formed.

A pressure of preferably about 10 to 1000 MPa, more preferably about 40 to 200 MPa may be applied for pressure molding, but in some cases, atmospheric pressure is also possible. If the pressure is too low, it may be difficult to densify the specimen sufficiently, while if the pressure is too high, the production cost of the device for the production of cemented carbide material is expensive, which may also cause a problem of economical deterioration. It is preferable to pressurize.

As described above, in the pressurized state, the mixed powder of the metal carbide nanopowder and the metal binder powder is sintered, and during the sintering process, the metal binder component becomes a liquid phase or a molten phase, the rearrangement of the carbide, and the easy atomization Diffusion, etc. will occur. Due to the metal binder component, the densification temperature of the metal carbide-metal composite is considerably lower than the densification temperature of the corresponding metal carbide.

According to an embodiment of the present invention, the sintering process can be carried out under atmospheric or vacuum conditions, but when it is carried out under vacuum conditions, a sintered body of good quality can be obtained due to oxidation inhibition, but it takes a long time and a manufacturing apparatus. Since it is expensive, it is preferable to adjust a degree of vacuum suitably according to the material used. Typically, the vacuum conditions are suitable in the range of about 0.01 to 1 Torr, and may be preferable since the oxidation of the metal can be effectively suppressed, especially when set to a vacuum level of about 0.04 Torr.

According to a preferred aspect of the present invention, the heat generated by the current in the sintering process may be used, and heat generated by the induced current or the pulsed current may be used.

In the case of using an induction current, Joule heat generated by the induction current is applied by applying a high frequency induction current to an outer coil, for example, a conductive metal coil such as a copper coil, which surrounds the outer surface of the mixed powder without contacting the outer surface thereof. The mixed powder is indirectly heated through. The frequency of the high frequency induction current applied to the external coil is typically in the range of about 1 to 100 Hz. In the case of using high frequency induction heating, the frequency range of the induced current can be appropriately adjusted according to the size of the sintered object or the specimen because the penetration depth of the high frequency current depends on the frequency. For example, when the sintered object is large, it is preferable to lower the frequency because the penetration depth of the induced current must be increased.

On the other hand, in the case of using a pulse current, a pulse current is applied to the die member in which the mixed powder is accommodated, and heat required for sintering is supplied by Joule heat generated thereby. The period of the pulse current is preferably in the range of about 1 mA to 1 mA, since the shorter the pulse period, the easier the trapped gas is released and the easier the sintering is.

On the other hand, the heating rate in the sintering process is preferably set to about 100 to 5000 ℃ / min, more preferably about 100 to 1000 ℃ / min. If the heating rate is too low, the grain growth may occur as the time required for sintering increases, while in the case where the heating rate is too high, there may be a problem that thermal stress occurs in the sintering object. Therefore, the above-described heating rate range is preferable. The sintering temperature may vary depending on the type of metal carbide and metal binder used, for example, the sintering temperature may be set such that the metal binder may exist in a liquid phase or a molten phase.

As the press molding and sintering proceed while heating the mixed powder by the induction current heating / pressurizing sintering method or the pulse current heating / pressurizing sintering method as described above, the resulting sintered object (or cemented carbide material) shrinks while being densified by the pressure continuously applied. Is reduced, and when this densification process is completed so that the shrinkage length no longer changes substantially, it is possible to block the induced current or the pulse current and to depressurize.

From the time when the pressure and the induction current or the pulse current is applied to the mixed powder as described above, the induction current or the pulse current is increased as the sintered object (that is, the cemented carbide material) reaches a densified state, that is, the state in which the shrinkage length no longer changes. The time to shut off and remove the pressure applied to the sintering object may typically take a short time, within about 5 minutes, even within about 2 minutes. As such, in the embodiment according to the present invention, the metal carbide-metal carbide material having a dense nanostructure can be produced in a short time without pore formation in the metal carbide.

As a subsequent step, a cooling step for the press-molded and sintered products is carried out until just before the interruption of the current, so that conventional methods known in the art, for example, air-cooled cooling methods and the like can be used. At this time, it is preferably cooled to room temperature, the cooling rate is not particularly limited, it is suitable if it is about 100 to 500 ℃ / min.

According to the above-described process, a metal carbide-metal carbide material or composite material of the final nanostructure can be obtained. Since a separate post-treatment process is not required, it can be easily produced by a single process. In particular, the grain size of the cemented carbide material prepared according to the present invention is preferably in the range of about 10 to 100 nm, more preferably in the range of about 10 to 40 nm. The mechanical properties of can be improved at the same time.

As described above, the nanostructured metal carbide-metal carbide material can preferably be produced using an induction current heating / pressurizing sintering apparatus, or a pulse current heating / pressurizing sintering apparatus. Preferably, the apparatus which has a structure mentioned later can be used.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a schematic configuration of an induction current heating / pressurizing sintering apparatus that can be used for producing a nanostructured metal carbide-metal carbide material according to a preferred embodiment of the present invention.

According to the drawing, the induction current heating / pressurizing sintering apparatus 100 includes a die member 110, a pressing member 120, and an induction current generating member 130.

The die member 110 is for accommodating a mixed powder (a mixture of a nano powder of a metal carbide and a metal binder powder), and preferably may be made of graphite material. In addition, a through hole is formed in the die member 110, and the mixed powder is accommodated in a central portion of the inner space of the through hole. At this time, the vacuum degree of the space inside the through hole filled with the mixed powder is preferably maintained in the range of about 0.01 to 1 Torr.

The pressing member 120 serves to apply pressure transmitted from an external pressure generating device to the mixed powder located inside the through hole, and are respectively inserted into the upper and lower portions of the through hole to apply uniaxial pressure. do. As such, the sintered object may be densified due to the pressure applied from the pressing member 120. In addition, in order to measure the change in shrinkage length of the sintered object corresponding to the index of the degree of densification, a linear displacement differential transformer (LVDT) may be attached to the movable portion where the through hole and the pressing member 120 are connected. At this time, it is preferable to apply a pressure of about 10 to 1000 MPa through the pressing member 120.

On the other hand, the induction current generating member 130 is configured to be spaced apart around the die member 110, and serves to generate an induction current. The induction current generating member 130 is made of a high frequency current coil, and indirect heat is applied to the die member 110 and the sintering object (mixed powder) by the induction current generated from the applied current, thereby sintering under pressure. Lose. At this time, it is preferable to flow an induction current having a frequency in the range of about 1 to 100 kHz to an external (induction) coil, and the heating rate by the induction current is preferably about 100 to 5000 ° C / min.

FIG. 2 is a schematic illustration of a die assembly of a pulsed current heating / pressurizing sintering apparatus usable for producing nanostructured metal carbide-metal carbide materials according to a preferred embodiment of the present invention.

In general, the pulse current heating / pressurizing sintering apparatus includes a water-cooled vacuum chamber, a die assembly, a pulse current supply member, a pressing member, a vacuum member, a cooling member, and various control and measurement members. The water-cooled vacuum chamber is a container (for example, stainless steel) for controlling the atmosphere of the press molding and sintering process, and may be provided with a double container having a viewing window for internal monitoring and a door for mounting the die assembly. It is configured to flow the coolant therein.

Referring to the drawings, the die assembly 200 of the pulse current heating / pressure sintering apparatus is, for example, a vertical punch 210, a cylindrical die 220 and a vertical pressure block of insulating material such as alumina (high purity graphite material) 230). At this time, the mixed powder is filled in the inner space formed by the upper and lower punches 210 and the cylindrical die 220, the vacuum of the inner space can be maintained at about 0.01 to 1 Torr, even at atmospheric pressure depending on the material used It is possible. The pulse current supply member 300 supplies a pulse current to the sintered object by the operation of the control switch 310, the pressing device (not shown) is the upper and lower punch of the die assembly 200 through the pressing block 230 ( A uniaxial pressure is applied to 210, and a linear displacement differential transformer LVDT is attached to the movable portion of the hydraulic cylinder to measure the change in length of the sintered object.

The pressure applied through the upper and lower punches 210 may be determined experimentally to the extent that the sintered object can be sufficiently densified, preferably in the range of about 10 to 1000 MPa. The pulse current is applied and maintained until the densification of the mixed powder is made during sintering after press molding, where the pulse period is suitably in the range of about 1 ms to 1 ms. In addition, the heating rate by the pulse current is preferably adjusted to about 100 to 5000 ℃ / min. In addition, conventional rotary pumps and cooling water pumps may be used as the vacuum member and the cooling member, respectively, and the control and measurement member controls process factors such as pressure and current, and measures various data during the process.

The following examples are provided to aid the understanding of the present invention and are not intended to limit the present invention to the following examples.

Example 1

15 g of titanium carbide raw powder (purity 99.5%, Alfa) having a particle size of 1.3 µm was ball milled using a Pulverisette 5 planetary mill to obtain a nanopowder having a particle size of about 25 nm (250 rpm; 10 hours). WC balls 5 mm in diameter; weight ratio of balls / powder 30; room temperature). Iron (<2 μm, 99.9% purity, Alfa), nickel (<2 μm, 99.8% purity, Sigma-Aldrich) and cobalt (<3 μm, 99.7% purity, Sigma equivalent to 10 vol.% Of the nanopowder -Aldrich) were each added and each of them was mixed uniformly for 24 hours using a universal milling machine. Each of the three mixed powders was filled in a graphite die (outer diameter 45 mm; inner diameter 20 mm; height 40 mm) of the die member 110 shown in FIG. 1, and then subjected to a uniaxial pressure of 80 MPa and a vacuum of 0.04 Torr. Created the atmosphere.

A high frequency induction current heating / pressurization sintering was started by applying a current of 14.4 mA to the external coil, that is, the induction current generating member 130 shown in FIG. At this time, the heating rate by Joule heat generated by the induction current heating was to be 500 ℃ / min. At this time, the temperature of the graphite die surface was measured by an optical thermometer (pyrometer).

The change in shrinkage length of the specimen during press molding and sintering was observed with a linear displacement differential transformer (LVDT) to remove the induced current and pressure at the point of stabilization without any change in length, and then cooled to room temperature, respectively. -10 vol.% Fe, TiC-10 vol.% Ni, and TiC-10 vol.% Co cemented carbide were obtained.

Example 2

Instead of the induction current heating / pressurizing sintering apparatus, the pulse current heating / pressurizing sintering apparatus shown in FIG. 2 was used. In addition, a metal carbide-metal cemented carbide material having a nanostructure was prepared by a method similar to Example 1 as follows.

The mixed powder obtained in Example 1 was packed into a cylindrical die (outer diameter of 45 mm; inner diameter of 20 mm; height of 40 mm) of graphite material and mounted in a vacuum state of about 0.4 Torr. Thereafter, a uniaxial pressure of 80 MPa was applied to the mixed powder to prepare a molded body. A constant pulse (periodic: 10 mA) of current was applied to the graphite die and the specimen by continuously applying a pressure of 80 MPa to the molded body, and the specimen was heated at a heating rate of 1000 ° C./min by Joule heat. At this time, the change in shrinkage length of the specimen during press molding and sintering was observed with a linear displacement differential transformer (LVDT) to remove the pulse current and the pressure at the point of stabilization without change in length. The specimen was then cooled to room temperature.

Experiment result

In Example 1, the nanopowder of TiC and the metal (Fe, Ni, and Co) binder powder were mixed, and then the temperature and shrinkage length change during the high frequency induction current heating / pressurizing sintering was measured. Shown in 4 is a scanning electron microscope (SEM) photograph of the sintered body, and FIG. 5 is a graph showing an X-ray diffraction (XRD) pattern of a sintered body of TiC-10 vol.% Metal (Fe, Ni and Co, respectively). to be.

3 illustrates a change in temperature (□) and shrinkage displacement (■ ▲ ◆) according to heating time during high frequency induction current heating / pressurizing sintering. From the figure, a dense nanostructured titanium carbide having almost no pores at relatively low temperature of 1150 ° C. (TiC alone densification temperature is about 1350 ° C.) in a short time within 2 minutes using a high frequency induction current heating / pressurizing sintering method. It can be confirmed that a metal (Fe, Ni and Co) sintered body was obtained.

In Figure 4, (a) is TiC-10vol.% Fe, (b) is TiC-10vol.% Co, and (c) is a SEM photograph of each TiC-10vol.% Ni. From the figure, it can be seen that a dense titanium carbide-metal phase was obtained after sintering at 1150 ° C., which means that the heating / pressurizing sintering was completed at a heating temperature with little change in shrinkage length.

In FIG. 5, (a) shows TiC-10vol.% Fe, (b) shows TiC-10vol.% Ni, and (c) shows TiC-10vol.% Co. Only TiC peaks were observed in the figure, and Fe, Ni and Co can be confirmed by X-ray mapping.

The grain size was determined by Suryanarayana and Grant Norton's formula using X-ray diffraction half value breadth, which was about 80 nm, 44 nm, and 61 nm, respectively, indicating that grain growth was effectively suppressed during the sintering process. do.

Further, in the prior art in which the metal carbide and the metal binder are pressed together and then sintered together, the grain size of the final cemented carbide material is about 400 nm or more, whereas the metal carbide is first nano-powdered and then mixed with the metal binder to press sinter it. In the examples, cemented carbide materials having significantly lower grain sizes (ie nanostructured) of up to 100 nm were obtained.

Evaluation of Mechanical Properties

For each of the three cemented carbide materials (TiC-10vol.% Fe, TiC-10vol.% Co, and TiC-10vol.% Ni) obtained in Example 1, the hardness and fracture toughness were as follows. Was measured.

Hardness: Measured by Vickers hardness tester.

Fracture Toughness: Cracks were propagated at the indented edges when held at 30 kgf for 15 seconds using a Vickers hardness tester. The crack length was measured, and fracture toughness was measured using an Antis equation represented by Equation 1 below.

[Equation 1]

K _IC = 0.016 ( E / H ) ^1/2 ( P / C ) ^3/2

Where E is the Young's modulus, H is the hardness, P is the load, and C is the length of the crack.

The measurement results of hardness and fracture toughness are shown in Table 1 below.

Table 1 Hardness (㎏ / ㎜ ² ) Fracture Toughness (MPa.m ^1/2 ) TiC-10vol.% Co 1780 8.3 TiC-10vol.% Ni 1822 8.6 TiC-10vol.% Fe 1905 8.5

From the table, it was confirmed that the metal carbide-metal carbide material prepared according to the method according to the invention exhibits particularly improved hardness properties.

In addition, Example 2 using the pulse current heating / pressurizing sintering apparatus also obtained similar results as described above.

The method for producing a metal carbide-metal carbide material having a nanostructure according to the present invention described above is not limited to the above-described embodiment, and the present invention belongs without departing from the gist of the present invention as claimed in the following claims. It will be appreciated that anyone with ordinary knowledge in the art can include various changes and implementations.

Claims (18)

a) nanopowdering the metal carbide; b) mixing the metal binder powder with the nano powder of the metal carbide; c) press molding and sintering by applying heat generated by a current to the mixed powder; And d) cooling the press-formed and sintered product; Wherein the step c) is carried out until the contraction length of the product being press-molded and sintered no longer changes. The metal carbide of claim 1, wherein the metal carbide is selected from the group consisting of titanium carbide (TiC), tungsten carbide (WC), silicon carbide (SiC), tantalum carbide (TaC), vanadium carbide (VC), and niobium carbide (NbC). 1 or 2 or more and the metal binder is selected from the group consisting of iron (Fe), nickel (Ni) and cobalt (Co), characterized in that the metal carbide-metal carbide material of the nanostructure. How to manufacture. The method of claim 1, wherein the nanopowder of metal carbide obtained from step a) has a particle size of 100 nm or less. The method of claim 1, wherein step a) is performed by ball milling. The method of claim 1, wherein step c) is performed within 5 minutes. The method according to claim 1, wherein the heat generated by the current is heat generated by an induced current. The method of claim 6, wherein the induction current is an induction current having a frequency of 1 to 100 Hz. The method of claim 1, wherein the heat generated by the current is a heat generated by a pulse current. 9. The method of claim 8, wherein the pulse current is a pulse current having a period of 1 mA to 1 mA. The method according to claim 1, wherein the heating rate of step c) is 100 to 5000 ° C / min. The method of claim 1, wherein the press forming of step c) is performed at a pressure of 10 to 1000 MPa. The method of claim 1, wherein step c) is performed under vacuum conditions of 0.01 to 1 Torr. The method of claim 1, wherein the shrinkage length change of the press-formed and sintered product is measured by a linear displacement differential transformer (LVDT). The method of claim 1, wherein the mixed amount of the metal binder powder is in the range of 1 to 50% by volume based on the mixed powder. The method of claim 1, wherein the step d) is to cool the press-molded and sintered product to room temperature. The method of claim 1, wherein the particle size of the metal binder powder is in the range of 0.5 to 50 μm. 5. The method of claim 4, wherein the ball mill is vibratory ball milling, attrition ball milling or high energy ball milling. A nanostructured metal carbide-metal carbide material according to any one of claims 1 to 17, characterized in that the grain size ranges from 10 to 100 nm.

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