KR101101243B1 - The preparing method of alloy/metal powder dispersed with nano ceramic using the high-speed milling machine and the resultant alloy/metal powder dispersed with nano ceramic - Google Patents

Abstract

The present invention comprises the steps of mixing the Ni- or Fe-based metal powder, and the ceramic powder (step 1); And mixing the powder prepared in step 1 with the steel balls into the rotary container in the contact rotary high-speed milling apparatus, and then rotating the rotating shaft at 800-1200 rpm in a vacuum or argon atmosphere, and the rotating container has a rotating speed and a rotating container radius. The high speed mechanical milling apparatus includes a step (step 2) of about 2000-2900 rpm, which rotates in a direction opposite to the direction of rotation of the rotating shaft, and milling for a short time of 30-70 minutes. The present invention relates to a method for producing nano-ceramic dispersion-reinforced alloy / metal powder in a short time. The present invention by using a ball mill equipment of high rotational speed and high energy, Ni-Cr, Ni-Fe, Ni-Al, Ni-Ti, Ni-Co, Ni-Mo, Ni-Si, Ni-W, Ni-Ta , Ni-Zr, Ni-C, Ni-N-based and Fe-Cr, Fe-Ni, Fe-Al, Fe-Ti, Fe-Co, Fe-Mo, Fe-Si, Fe-W, Fe-Ta, Mechanical alloying of ternary or higher alloying elements, including binary alloys such as Fe-Zr, Fe-C, Fe-N, etc. is possible, and Y ₂ O ₃ , Al ₂ O ₃ , ThO ₂ , SiC, TiC By miniaturizing various ceramic powders such as, TiN, TiCN, NbC, WC, B ₄ C, BN to nano size and uniformly dispersing them in a metal or alloy base, a nano ceramic dispersion reinforced alloy / metal powder can be produced in a short time. It can be usefully used to prepare uniform and fine alloy powder.

Metal Powder, Ceramic Powder, Contact Rotary, Ceramic Dispersion Alloy / Metal Powder

Description

Manufacture method of nano ceramic dispersion reinforced alloy / metal powder using high speed mechanical milling apparatus and nano ceramic dispersion reinforced alloy / metal powder prepared according to the present invention and the resultant alloy / metal powder dispersed with nano ceramic}

The present invention relates to a method for producing a nano-ceramic dispersion-reinforced alloy / metal powder using a high speed mechanical milling apparatus, and to a nano-ceramic dispersion-reinforced alloy / metal powder produced accordingly.

Mechanical alloying ("MA") method was applied in the 1960s to simultaneously obtain the precipitation strengthening effect of Ni-based super heat-resistant alloys for gas turbines and the dispersion strengthening effect of microoxides at high temperatures (JSBenjamin, RDSchelleng). , Metall. Trans., 12A (1981) 1827). The MA method is to produce composite metal powder on a uniform and fine alloy by repeating the process of cold welding and fracture the powder continuously by high energy ball milling the powders of alloying elements. Method of alloying powder metallurgy (C. Suryanarayana, Prog. Mater. Sci., 46 (2001) 1-184). The MA method can be obtained in a fine dispersed phase by mixing elements that are difficult to alloy. Since the alloying and dispersing of elemental components are performed in a solid phase reaction rather than in a liquid phase, the MA method is very uniform and has excellent organizational characteristics compared to quench solidification and dissolution casting techniques. You can expect In addition, since the fine oxide can be uniformly dispersed, the addition of a small amount of oxide can achieve crystallization, dispersion, and solid solution strengthening effect very efficiently.

In the case of metal-metal alloying, researches for improving the mechanical and physical properties of materials using the MA method using ball milling have been actively conducted in various fields.

For example, Inco, a leading MA material manufacturer, charges raw material powder for the production of MA956, a Fe-based superheat-resistant alloy, and mechanically alloys it for about 30 hours in an Ar atmosphere. For the production of Ni-Cr alloy, mechanical alloying was performed by using SPEX mill for about 14 hours (ANStreletskii, THCourtney, Mater, Sci and Eng.A., 282 (2000)). 213), Ni-Cr-Fe-based alloys have been reported to be characterized by alloying powder after milling at 320 rpm for about 30 hours using an attritor (IHKim, WLLee, SHKo, J. Kor. Powd. Met. Ins., 15 (2008) 23). As such, in the conventional mechanical alloying process, milling techniques such as an attritor, planetary ball mill, and specex mill have been generally used, but these techniques have low milling speeds and thus steel balls. The impact energy of the low is a problem that must be performed for a long time up to several tens of milling for uniform alloying.

In addition, in the nano-composite technology of ceramics, it is difficult to refine the coarse ceramic particles to nano size by the conventional MA method, and expensive nano-ceramic powders (tens of nanometers) are dispersed and milled in metal or alloy bases for a long time. Reinforcing alloy powder is manufactured.

For example, for the production of oxide dispersion-enhanced ferritic steels for nuclear power plant applications, using a Y ₂ O ₃ powder and Fe-Cr mixed powder of about 20 nm in a grinder (attritor) at a speed of 220 rpm for 48 hours Results of alloying have been reported (S. Ukai, S. Mizuta, T. Yoshitake, T. Okuda, M. Fujiwara, S. Hagi, T. Kobayashi, J. Nuclear Materials, 283-287 (2000) 702) It has been reported that mechanical alloying was carried out at 500 rpm for 16 hours using a planetary ball mill (Retsch PM200) to disperse Y ₂ O ₃ powder having a size of 20 nm for Fe-Ni-Cr ternary alloy steels. MP Phaniraj, DI Kim, JH Shim, YW Cho, Acta Materialia, 57 (2009) 1856).

However, most of the conventional ball milling processes have low milling speed and milling energy, and thus, inefficient alloying requires a long time of milling for several tens of hours for uniform alloying, and a temperature of the powder container during the long alloying process is about 100-220 ° C. There is a problem such as a large rise. In addition, in the manufacture of nano ceramic composite materials such as oxide dispersion-reinforced alloys, due to the increased manufacturing cost and the high cost of materials caused by the use of expensive dozens of nano-size powders, There is a problem that is difficult to apply.

Accordingly, the present inventors apply a high milling speed and a high energy milling technology, which not only simultaneously realizes metal-metal alloying and nano-compositing nano ceramics in a shorter time period than conventional milling processes, but also has a very uniform and fine structure. A method for producing a ceramic dispersion hardened alloy / metal powder was developed and the present invention was completed.

An object of the present invention is to provide a method for producing nano-ceramic dispersion-reinforced alloy / metal powder using a high speed mechanical milling apparatus.

In addition, another object of the present invention to provide a uniform nano ceramic dispersion strengthening alloy / metal powder.

In order to achieve the above object, the present invention comprises the steps of mixing the Ni-based or Fe-based metal powder, and the ceramic powder (step 1); And mixing the powder prepared in step 1 with the steel balls in the rotary container in the contact rotary high-speed milling apparatus and rotating the rotating shaft at 800-1200 rpm in a vacuum or argon atmosphere, and rotating the rotating shaft at 2000-2900 rpm. It provides a method for producing nano-ceramic dispersion-reinforced alloy / metal powder in a short time using a high speed mechanical milling device which is rotated in the opposite direction and milling for a short time of 30 to 70 minutes (step 2). .

In addition, the present invention provides a uniform and fine nano-ceramic dispersion-reinforced alloy / metal powder.

The present invention by using a ball mill equipment of high rotational speed and high energy, Ni-Cr, Ni-Fe, Ni-Al, Ni-Ti, Ni-Co, Ni-Mo, Ni-Si, Ni-W, Ni-Ta , Ni-Zr, Ni-C, Ni-N-based and Fe-Cr, Fe-Ni, Fe-Al, Fe-Ti, Fe-Co, Fe-Mo, Fe-Si, Fe-W, Fe-Ta, Mechanical alloying of ternary or higher alloying elements, including binary alloys such as Fe-Zr, Fe-C, Fe-N, etc. is possible, and Y ₂ O ₃ , Al ₂ O ₃ , ThO ₂ , SiC, TiC By miniaturizing various ceramic powders such as, TiN, TiCN, NbC, WC, B ₄ C, BN to nano size and uniformly dispersing them in a metal or alloy base, a nano ceramic dispersion reinforced alloy / metal powder can be produced in a short time. It can be usefully used to prepare uniform and fine alloy powder.

The present invention comprises the steps of mixing the Ni- or Fe-based metal powder, and the ceramic powder (step 1); And

After the mixed powder prepared in step 1 is put together with the steel balls in the rotating rotary mill in the contact rotary high speed milling apparatus, the rotating shaft rotates at 800-1200 rpm in a vacuum or argon atmosphere, and the rotating container rotates at 2000-2900 rpm. It is rotated in the opposite direction to provide a method for producing nano-ceramic dispersion-reinforced alloy / metal powder in a short time using a high speed mechanical milling device comprising the step (step 2) of milling for a short time of 30-70 minutes.

Hereinafter, the present invention will be described in detail step by step.

Step 1 according to the present invention is a step of mixing Ni-based or Fe-based metal powder, and ceramic powder.

The Ni-based metal powder of step 1 may use an alloy of two or more bases with a metal capable of alloying with Ni, and the metal capable of alloying with Ni may be Cr, Fe, Al, Ti, Co, Mo, Si, W, Ta, Zr, C, N and the like can be used.

In addition, the Fe-based metal powder of the step 1 may be used an alloy of two or more based on the metal alloying with Fe, the metal alloying with Fe is Cr, Ni, Al, Ti, Co, Mo, Si, W, Ta, Zr, C, N and the like can be used.

Further, the ceramic powder of step 1 may be Y ₂ O ₃ , Al ₂ O ₃ , ThO ₂ , SiC, TiC, TiN, TiCN, NbC, WC, B ₄ C and BN.

In addition, the size of the Ni constituting the Ni-based metal of the step 1, the metal mixed with the Ni, and the ceramic powder mixed with them are preferably 1-100 μm, 1-100 μm and 1-200 μm, respectively. Do. If the size of the Ni-based metal and the metal powder mixed with the Ni is less than 1 μm, the cost of the raw material increases, and there is a problem that a uniform alloying powder cannot be produced. In this case, there is a problem that the alloying process time is long. Furthermore, when the size of the ceramic powder is less than 1 μm, the raw material cost increases, and there is a problem that a uniform alloying powder cannot be prepared, and when the size of the ceramic powder exceeds 200 μm, the process time for nano- and uniform dispersion becomes longer. there is a problem.

In addition, the size of Fe constituting the Fe-based metal of the step 1, the metal mixed with the Fe, and the ceramic powder mixed with them are preferably 1-100 ㎛, 1-100 ㎛ and 1-200 ㎛ Do. If the size of the metal powder mixed with Fe and Fe constituting the Fe-based metal is less than 1 μm, the raw material cost increases, there is a problem that can not produce a uniform alloying powder, exceeding 100 μm In this case, there is a problem that the alloying process time is long. In addition, when the size of the ceramic powder is less than 1 ㎛ increase in raw material cost, there is a problem that can not produce a uniform alloying powder, if it exceeds 200 ㎛ is a long process time for nano- and uniform dispersion there is a problem.

Next, step 2 according to the present invention is a step of milling in a vacuum or argon atmosphere after the mixture powder prepared in step 1 is added to the rotary container in the contact rotary high-speed milling apparatus with steel balls.

The milling can be performed using the contact rotary high speed milling apparatus shown in FIG. In the milling apparatus, when the shaft 6 rotates, the powder container 4 rotates at a high speed in a direction opposite to the guide wall surface 3 of the chamber 5 and the rotation shaft. At this time, inside the container 4, the steel balls and powders are located on the wall of the container due to the centrifugal force caused by the rotation of the rotating shaft, and the steel balls are optimal in the rotational direction of the container 4 by the friction force between the wall of the container and the steel ball. After moving to the hitting point (point (c) P of FIG. 1), the powders can be hit easily and accurately by hitting the opposite container wall, and uniform and fine alloy powders can be produced by their repeated collision and hitting. have. In addition, the rotating container of step 2 is preferably a heat treatment special steel (SKD11) in order to minimize the influence of impurities during milling, but is not limited thereto.

Furthermore, the weight ratio of the ball and the powder in the rotating container of step 2 is preferably 10-20: 1. If the weight ratio of the ball is less than 10, there is a problem in that the number of balls pulverizing the powder is not uniform and finely manufactured. If the ball is more than 20, the friction ratio with the ball is high, so that the inside of the rotating container is high. There is a problem that the temperature rises and the milling effect is lowered, thereby reducing the recovery of the powder.

In the milling of the step 2, the rotating shaft rotates at 800-1200 rpm, and the rotating container is determined by the rotating speed of the rotating shaft and the rotating container radius, and is rotated in the range of 2000-2900 rpm, for 30-70 minutes. It is preferable to carry out. If the speed of the rotating shaft is less than 800 rpm, there is a problem in that the process time for alloying the powder and nano-forming the ceramic powder becomes long, and in the case of exceeding 1200 rpm, the balance, stability and durability of the equipment are deteriorated. There is. In addition, when the milling time is less than 30 minutes, not completely solid solution and alloying between the metal powder does not form the alloy powder, it is difficult to nano-dispersion of the ceramic, the production of uniform nano ceramic dispersion reinforced alloy / metal powder If there is a difficult problem and exceeds 70 minutes, since the final nano-ceramic dispersion-reinforced alloy / metal powder is already manufactured, it is preferably 70 minutes or less in terms of energy efficiency to shorten the process time.

The present invention also provides a nano-ceramic dispersion-reinforced alloy / metal powder having a uniform and fine structure produced by the above-described manufacturing method.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are merely to illustrate the invention, the content of the present invention is not limited by the following examples.

Example 1 Preparation of Ni-Cr-Y ₂ O ₃ Nano Ceramic Dispersion-Reinforced Alloy Powder

Step 1: Mixing Ni and Cr Metal Powder and Ceramic Powder

Ni-Cr-Y ₂ O _{3 has} a composition ratio of Ni-Cr-Y ₂ O ₃ containing 99% pure Ni and Cr metal powders having a size of about 50 μm and 99.999% pure Y ₂ O ₃ ceramic powders having a size of about 70 μm. : 2 wt% was added and mixed uniformly with a three-dimensional mixer.

Step 2: milling the mixed powder prepared in step 1 into a rotating container

In order to minimize the influence of impurities during milling, the mixed powder prepared in step 1 was used as a heat treatment special steel (SKD11), and the inside of the rotating container was vacuum or argon atmosphere to prevent oxidation and excessive pressure welding during the milling process. Was prepared. Milling was carried out with a high speed milling apparatus (Pyeongmyeong Science, P-100) of Figure 1, the weight ratio of the ball and powder in the rotating vessel was set to 15: 1. After uniformly mixed Ni-Cr-Y ₂ O ₃ powder was added to the rotating container together with steel balls, the speed of the rotating container was milled at about 2600 rpm for 40 minutes. Cooling water was sprayed to minimize the increase in the internal temperature of the rotating vessel to prepare Ni-Cr-Y ₂ O ₃ nano ceramic dispersion reinforced alloy powder.

Example 2 Preparation of Fe-Cr-Y ₂ O ₃ Nano Ceramic Dispersion-Reinforced Alloy Powder

Metal powder is Fe and Cr, Y ₂ O ₃ is used as the ceramic powder, and the composition of Fe-Cr-Y ₂ O ₃ is about 84: 14: 2% by weight, except that the same method as in Example 1 Fe-Cr-Y ₂ O ₃ nano ceramic dispersion reinforced alloy powder was prepared.

Comparative Example 1 Ni-Cr alloy prepared by a conventional method

As a conventional manufacturing method reported by ANStreletskii et al. (ANStreletskii, THCourtney, Mater, Sci and Eng. A., 282 (2000) 213), 80 Ni-20 Cr for the preparation of Ni-Cr alloys. The Ni-Cr alloy was manufactured by mechanical alloying for about 14 hours using a SPEX mill at a ratio of.

FIG. 2 is a graph showing changes in lattice constant of Ni (interval, length, height between atoms in a crystal of molecules of the same shape and structure) through X-ray diffraction. 2, it can be seen that as the mechanical alloying (MA) process time increases, Cr is dissolved in Ni, and the lattice constant gradually increases, and the lattice constant is constant after about 600 minutes, indicating that the alloying is completed. Can be.

Experimental Example 1 Analysis of Crystal Structure of Ni-Cr-Y ₂ O ₃ Nano Ceramics Dispersion-Reinforced Alloy Powder

X-ray diffraction apparatus (XRD, Rigaku, D / MAX-2500) for the crystal structure analysis and lattice constant of Ni-Cr-Y ₂ O ₃ nano ceramic dispersion-reinforced alloy powders manufactured using high-speed mechanical milling equipment And the results are shown in FIGS. 3 and 4.

As shown in FIG. 3, as the milling time increases, peak broadening occurs due to grain refinement and internal non-uniform deformation, and the 2θ value of the Ni peak tends to decrease gradually, and the atomic radius is larger than Ni. It can be seen that the phenomenon occurs when Cr is dissolved. In addition, the Cr peak remained until about 10 minutes of milling time, but after 40 minutes (Example 1), the Cr peak disappeared, indicating that Cr was completely dissolved in Ni and alloyed.

In addition, as shown in Figure 4, it can be seen that the lattice constant of Ni gradually increases as Cr is dissolved in the Ni base as the milling time increases, and since the lattice constant becomes constant after 40 minutes of milling, the alloying is completed. Can be.

Experimental Example 2 Microstructure Analysis of Ni-Cr-Y ₂ O ₃ Nano Ceramic Dispersion-Reinforced Alloy Powder

Energy spectroscopy (EDS) using a transmission electron microscope (TEM, JEOL, JEM-2100F) to analyze the microstructure of Ni-Cr-Y ₂ O ₃ nano ceramic dispersion-reinforced alloy powders prepared using a high-speed mechanical milling apparatus And limited field diffraction pattern (SADP) analysis, and the results are shown in FIGS. 5 and 6.

As shown in FIG. 5, in the alloy powder subjected to the milling time for 10 minutes, Ni and Cr were formed in a layered structure, and very fine Y ₂ O ₃ particles were also observed. In addition, in Example 1 in which the milling time was performed for 40 minutes, fine structures were observed, and the alloying was completed because Cr and Y ₂ O ₃ were uniformly dispersed throughout.

In addition, as shown in Figure 6, in the alloy powder after performing the milling time for 10 minutes it can be seen that the grain size is made finer in the form of a ring (ring), Ni and Cr are present together, so that sufficient solution It can be seen that it was not lost. On the other hand, in Example 1, which performed 40 minutes of milling time, it was confirmed that the alloy powder was composed of a finer structure, forming a complete ring shape, and since Cr disappeared and only Ni appeared, it was found that Cr was completely dissolved in Ni. have.

Experimental Example 3 Microstructure Analysis of Fe-Cr-Y ₂ O ₃ Nano Ceramics Dispersion-Reinforced Alloy Powder

In order to analyze the microstructure of the Fe-Cr-Y ₂ O ₃ nano-ceramic dispersion-reinforced alloy powder prepared by using a high-speed mechanical milling apparatus, energy spectroscopic analysis (EDS mapping) using a transmission electron microscope (TEM) was performed. The results are shown in FIG.

As shown in Figure 7, in the alloy powder was performed for 10 minutes milling time Fe and Cr and Y ₂ O ₃ was formed in a layered structure and showed a non-uniform dispersion state, but in the alloy powder was performed for 30 minutes milling time Fe Cr and Y ₂ O ₃ appear uniformly dispersed throughout the matrix, indicating that alloying was completed in a short time.

1 is a schematic drawing of a high speed milling apparatus used in the present invention ((a): side view, (b): top view and (c): impact mechanism of steel balls inside powder container);

2 is a graph showing a change in lattice constant with milling time of a Ni—Cr based alloy prepared by a conventional manufacturing method;

3 is an X-ray spectroscopic analysis (XRD) result of Ni-Cr-Y ₂ O ₃ nano ceramic dispersion-reinforced alloy powder with milling time;

Figure 4 is a graph showing the lattice constant change of Ni-Cr-Y ₂ O ₃ nano ceramic dispersion-reinforced alloy powder with milling time;

5 is an energy spectroscopic analysis (EDS mapping) result using a transmission electron microscope (TEM) showing the microstructure of Ni-Cr-Y ₂ O ₃ nano ceramic dispersion-reinforced alloy powder with milling time;

FIG. 6 is a result of limiting field diffraction pattern (SADP) using a transmission electron microscope (TEM) showing the microstructure of Ni-Cr-Y ₂ O ₃ nano ceramic dispersion-reinforced alloy powder with milling time; FIG. And

7 is an energy spectroscopic analysis (EDS mapping) result using a transmission electron microscope (TEM) showing the microstructure of the Fe-Cr-Y ₂ O ₃ nano-ceramic dispersion-reinforced alloy powder with milling time.

<Description of the symbols for the main parts of the drawings>

1: cooling water inlet 2: cover

3: rotating guide wall 4: container

5: chamber 6: rotating shaft

7: cooling water outlet 8: pulley

9: rotator 10: container holder

11: Container pocket

Claims (9)

In the method for producing nano-ceramic dispersion-reinforced alloy / metal powder in a short time using a high speed mechanical milling device, Mixing Ni- or Fe-based metal powder and ceramic powder (step 1); After the mixed powder prepared in Step 1 is introduced into the rotary container in the contact rotary high speed milling apparatus together with steel balls, the rotating shaft rotates at 800-1200 rpm in a vacuum or argon atmosphere, and the rotating container rotates at 2000-2900 rpm. Rotating in the opposite direction to milling for a short time of 30 to 70 minutes (step 2), Ni constituting the Ni-based metal of the step 1, the metal mixed with the Ni, and the ceramic powder mixed with these are 1-100 ㎛, 1-100 ㎛ and 1-200 ㎛, respectively Fe constituting the Fe-based metal of the step 1, the metal mixed with the Fe, and the size of the ceramic powder mixed with these are 1-100 ㎛, 1-100 ㎛ and 1-200 ㎛, respectively In the step 2, the weight ratio of the steel ball and the mixed powder in the rotating container is 10-20: 1 method for producing a nano ceramic dispersion strengthening alloy / metal powder. According to claim 1, wherein the Ni-based metal powder of step 1 is a method for producing a nano-ceramic dispersion-reinforced alloy / metal powder, characterized in that the alloy of two or more based on the alloying alloy with Ni. The method of claim 1, wherein the Fe-based metal powder of step 1 is a nano-ceramic dispersion-reinforced alloy / metal powder manufacturing method, characterized in that the alloy of the binary system of Fe and the metal or more capable of alloying. The method of claim 1, wherein the ceramic powder of step 1 is selected from the group consisting of Y ₂ O ₃ , Al ₂ O ₃ , ThO ₂ , SiC, TiC, TiN, TiCN, NbC, WC, B ₄ C and BN Method for producing a nano-ceramic dispersion-reinforced alloy / metal powder, characterized in that one. delete delete delete The method of claim 1, wherein the milling of the step 2, the powder container is rotated in contact with the guide wall in the chamber when the rotating shaft is rotated, the ball in the powder container is moved along the wall surface inside the container and hit the opposite wall powder particles A method of producing a nano-ceramic dispersion-reinforced alloy / metal powder, characterized in that the powder is crushed to give a strong impact to the alloy and finely pulverized. The nano ceramic dispersion strengthening alloy / metal powder manufactured using the method of manufacturing the nano ceramic dispersion strengthening alloy / metal powder of any one of Claims 1-4.

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