KR101271451B1 - Apparatus for making compound powders and method using the same - Google Patents

Abstract

An object of the present invention is to provide an apparatus capable of producing a compound powder and a method for producing an iron-boron compound powder having high hardness and excellent self-solubility and adhesion using such an apparatus. According to an aspect of the invention, the step of reacting the iron powder and the boron feed material charged in the retort with each other while rotating and heating the retort surrounded by the furnace body having a heating; Separating and removing the furnace body from the outer circumferential surface of the retort; And cooling the retort while rotating it. A method for preparing an iron-boron compound powder is provided.

Description

Apparatus for making compound powders and method using the same}

The present invention relates to a device capable of producing a compound powder and a method for producing an iron-boron compound powder using the same, and more particularly, to iron-boron compound (boronizing) to produce an iron-boron compound powder It is about a device and a method that can be.

In general, the wear resistant composite can be prepared by distributing a ceramic powder having high hardness and high wear resistance as a reinforced phase on a base made of metal. Various conventional high hardness, such as from tungsten carbide (WC), titanium carbide (TiC), titanium boride (TiB ₂₎ as the ceramic powder, the powder is also have been used. However, these powders are expensive, and when the composite is formed by gravity or centrifugal casting, the difference in specific gravity with the base metal is large, so that it is difficult to uniformly disperse uniformly, and the adhesive strength is low, resulting in a poor bonding strength with the base metal.

The iron-boron binary compound has FeB or Fe ₂ B depending on the content of boron, specifically, when the boron content is 8.83% by weight, forms a Fe ₂ B compound having a melting temperature of 1389 ° C, and is 16.23% by weight. The FeB compound which shows the high melting point of 1650 degreeC is formed. On the other hand, when the content of boron is 3.8% by weight, it shows a low melting temperature of 1177 ° C. Fe ₂ B shows specific gravity of 7.3g / cm 3 and hardness value of HK 1800 ~ 2000, FeB shows specific gravity of Hg 1900 ~ 2100 with specific gravity of 7.0 g / cm 3, excellent fluxing and adhesive force. Furthermore, the iron-boron compound has a specific gravity of about 7.5 g / cm 3, which does not show a significant difference from the iron-based metal, and is thus suitable for preparing a metal composite using gravity or centrifugal casting based on the iron-based metal material.

An object of the present invention is to provide an apparatus capable of producing a compound powder and a method for producing an iron-boron compound powder having high hardness and excellent self-solubility and adhesion using such an apparatus. However, these problems are exemplary and do not limit the scope of the present invention.

According to an aspect of the invention, the step of reacting the iron powder and the boron feed material charged in the retort with each other while rotating and heating the retort surrounded by the furnace body having a heating; Separating and removing the furnace body from the outer circumferential surface of the retort; And cooling the retort while rotating it. A method for preparing an iron-boron compound powder is provided.

The iron powder may include pure iron powder.

The iron powder may have a diameter in the range of 10 to 1000 μm.

The retort may be heated in the temperature range of 850 ℃ to 1050 ℃.

The boron supply material may include boron powder, boron compound powder and ferroboron powder.

The boron compound powder may include boron carbide (B ₄ C) powder or boron oxide (B ₂ O ₃ ) powder.

Meanwhile, the iron powder and the boron feed material may be reacted after further loading the activator powder into the retort, and the activator powder may be Na ₃ AlF ₆ , KBF ₄ , AlF ₃ , NaCl, NaF, CaF _2, and NH _4. It may include any one or more of Cl.

At this time, the boron feed material in the mixed powder of the iron powder, the boron feed material and the activator powder is in the range of 5 to 50% by weight and the activator powder may be in the range of 0.5 to 10% by weight.

Meanwhile, the average diameter of the boron feed material in powder form may have a smaller value than the average diameter of the iron powder.

On the other hand, the boron supply material may be boron gas or boron compound gas.

The boron gas or the boron compound gas may be mixed with a carrier gas and supplied as a mixed gas, wherein the boron compound gas is B ₂ H ₆ , BF ₃ , BCl ₃ , BI ₃ , BBr ₃ , (CH ₃ ) ₃ B And (C ₂ H ₅ ) ₃ B It may include any one.

The boron gas or boron compound gas may be in the range of 2 to 40% by volume in the mixed gas.

According to another aspect of the invention, a rotatable retort; And a furnace body including a frame surrounding the retort and a heating unit disposed to heat the retort in the frame.

The furnace body may include a plurality of partial furnaces which may be separately moved, and specifically, the partial furnaces may include a first subframe disposed to surround a portion of an outer circumferential surface of the retort and a first subframe disposed inside the first subframe. A first partial furnace including a heating unit; And a second sub-frame including a second sub frame disposed to surround the remaining portion of the outer surface of the retort and a second heating unit disposed inside the second sub frame.

According to the iron-boron compound powder manufacturing method and apparatus according to the embodiments of the present invention it is possible to produce an iron-boron compound powder having high hardness and excellent self-use and adhesion. Of course, the scope of the present invention is not limited by these effects.

1 to 3 are cross-sectional views schematically showing a compound powder manufacturing apparatus according to an embodiment of the present invention.
Figures 4a to 4c is a cross-sectional view of the iron-boron compound powder particles produced by the method for producing a compound powder according to an embodiment of the present invention.
5 is a cross-sectional structure of the iron-boron compound powder prepared by the experimental example of the present invention.
Figure 6 shows the X-ray diffraction analysis of the iron-boron compound powder prepared by the experimental example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Also, for convenience of explanation, the components may be exaggerated or reduced in size.

In the following embodiments, the x-axis, the y-axis, and the z-axis are not limited to three axes on the orthogonal coordinate system, and can be interpreted in a broad sense including the three axes. For example, the x-axis, y-axis, and z-axis may be orthogonal to each other, but may refer to different directions that are not orthogonal to each other.

1 is a cross-sectional view perpendicular to the x direction of the compound powder manufacturing apparatus 100 according to an embodiment of the present invention is shown. Referring to FIG. 1, the apparatus 100 for preparing a compound powder includes a retort 10 and a furnace body 20 which surrounds the retort 10 so as to be heated.

The retort 10 may have a hollow cylindrical pipe shape extending in the y direction. The retort 10 accommodates the mixed powder 40 in which two or more kinds of powders are mixed to prepare the compound powder in the interior space, and prevents the oxidation and sintering of the mixed powder 40 accommodated therein. It also has a function of uniformly mixing the powder mixed in the mixture powder 40. To this end, the retort 10 may rotate as shown by the arrow of FIG. 1 based on the center line extending in the y-axis direction. At the end of the retort 10 is provided a door 30 for charging the mixed powder 40.

The furnace body 20 includes a frame 21 surrounding the retort 10 and a heating unit 22 arranged to heat the retort 10 in the frame 21. The heating unit 22 may be in any form as long as it is a heating source capable of generating heat input to the outer circumferential surface of the retort 10 such as an electric resistor, a high frequency induction heater, a halogen lamp, and the like.

The furnace body 20 may each have a plurality of partial furnace bodies which can be moved separately. 2 is a cross-sectional view perpendicular to the extending direction (ie, y-direction of FIG. 1) of the retort 10 of the compound powder manufacturing apparatus 100 having a plurality of partial furnaces.

As an example, as shown in FIG. 2, the furnace body 20 may be composed of two partial furnaces, the first partial furnace 20a and the second partial furnace 20b. In this case, the first partial furnace 20a includes a first subframe 21a disposed to surround a part of the outer circumferential surface of the retort 10 and a first heating unit 22a disposed inside the first subframe 21a. The second partial furnace 20b includes a second subframe 21b disposed to surround the remaining portion of the outer circumferential surface of the retort 10 and a second heating unit 22b disposed inside the second subframe 21b. do.

At this time, as shown in Figure 2, the first partial furnace 20a is disposed on the upper side of the retort 10 and the second partial furnace 20b is disposed on the lower side of the retort 10, the present invention The present invention is not limited thereto, and the first partial furnace body and the second partial furnace body may be disposed on the left side and the right side of the retort 10, respectively.

As described above, each of the partial furnaces 20a and 20b constituting the furnace body 20 may be combined on the outer circumferential surface of the retort 10 to heat the retort 10 and, on the contrary, separately to cool the retort 10. Can be moved to be removed from the outer circumferential surface of the retort 10. 3 illustrates a case in which the furnace body 20 is removed from the retort 10.

The retort 10 may further include a member 50 for rotating the mixed powder 40 along the inner surface of the retort 10 during rotation.

In the case of the compound powder manufacturing apparatus 100, the desired compound powder may be prepared by inducing a reaction between materials constituting the mixed powder 40 by heating the mixed powder 40 charged in the retort 10. have.

As an example, the iron-boron compound powder may be manufactured using the compound powder manufacturing apparatus 100. That is, the iron powder and the boron supply material may be reacted with each other in the retort 10 as the mixed powder 40 to convert the iron powder into the iron-boron compound powder by boronizing the iron powder. In this case, the iron-boron compound may be FeB, Fe ₂ B or a mixture thereof.

In this case, the boron supply material may have a powder form as a material capable of supplying boron reacting with the iron powder. Therefore, the iron powder and the boron feed material powder is mixed with each other and charged in the retort 10 of the compound powder manufacturing apparatus 100. Of course, it is also possible to mount the iron powder and the boron feed material powder to the retort 10 separately.

As the iron powder, since the content of other alloying elements including carbon is low, iron powder commonly referred to in the art as pure iron may be used. This is because when iron contains other alloying elements, the diffusion rate of boron is lowered, thereby suppressing the formation of the iron-boron compound, making it difficult to form a uniform compound throughout the entire surface from the surface of the powder particles to the center. Such iron powder may be used by decarburizing a shot ball that is made of carbon steel and then used.

Meanwhile, the boron supply material may include any one or more of, for example, boron powder, boron compound powder, and ferroboron powder. In this case, the boron compound may include, for example, boron carbide (B ₄ C) or boron oxide (B ₂ O ₃ ).

At this time, the average diameter of the boron feed material powder may have a smaller value than the average diameter of the iron powder. This is to facilitate separation of the iron-boron compound powder produced after the boronation treatment and the remaining boron feed material powder. For example, the boron feed material powder may have a diameter in the range of 5 to 950 μm, and the iron powder may have a diameter in the range of 10 to 1000 μm.

If the diameter of the iron powder exceeds 1000㎛, it may be difficult to form a uniform compound from the surface of the iron powder from the surface of the iron powder to the inner center, if less than 10㎛ it will not be easy to separate from the remaining boron feed material powder Can be.

On the other hand, in the retort 10, as the mixed powder 40, in addition to the above-described iron powder and boron feed material may be further charged with an activator powder and then the iron powder and the boron feed material can be reacted. Such an activator may lower the reaction temperature of the iron powder and the boron feed material to further activate the reaction between iron and boron. Such activator may include any one or more of Na ₃ AlF ₆ , KBF ₄ , AlF ₃ , NaCl, NaF, CaF ₂ and NH ₄ Cl.

When the iron powder and the boron feed material and activator in powder form as a raw material are mixed with each other, the boron feed material may be in the range of 5 to 50% by weight, and the activator may be in the range of 0.5 to 10% by weight.

Next, the retort 10 is heated by using the heating unit 22 of the furnace body 20 while rotating the retort 10. At this time, when the furnace body 20 is not coupled to the outer circumferential surface of the retort 10, first, the furnace bodies 20 are moved to the outer circumferential surface of the retort 10 and coupled to each other, and then the retort is operated by operating the heating unit of the furnace body 20. (10) is heated.

When the furnace body 20 is composed of the first partial furnace body 20a on the upper side and the second partial furnace body 20b on the lower side as shown in FIG. 2, the respective partial furnace bodies 20a and 20b are moved to retort 10. ) To the outer circumferential surface.

Meanwhile, as the retort 10 is rotated as shown in FIG. 1 during heating, the powders in the mixed powder 40 are uniformly mixed with each other, and the heat transferred through the heating unit 22 is evenly transmitted in the mixed powder 40. The effect can be obtained.

As the retort 10 is heated as described above, the iron powder is boronated while the reaction between the iron powder and the boron feed material powder occurs in the mixed powder 40 charged in the retort 10. At this time, boron supplied from the boron supply material diffuses from the surface of the iron powder to the inside by the second law of diffusion.

In the case where the concentration of boron diffused into the iron powder is low, boron forms a diffusion layer in which solid solution is dissolved in iron, but as the concentration of boron increases, FeB or Fe ₂ B is formed as an iron-boron compound by the reaction between iron and boron. can do.

Therefore, the iron powder is changed into three regions of FeB (41), Fe ₂ B (42) and boron solid layer 43 in accordance with the concentration of boron as it enters from the surface during the boronization process as shown in FIG. FIG. 4A), or may be changed to two regions of the Fe ₂ B 42, the boron solid-solution layer 43 (FIG. 4B), or may be changed to include only the compound layer 44 which is all FeB or Fe ₂ B (FIG. 4A). 4c).

The thickness x of this compound layer depends on the treatment temperature and time according to the second law of diffusion (Equation 1). Where x is the compound layer thickness, t is the treatment time and D is the diffusion coefficient.

x = (Dt) ^1/2 (Equation 1)

As described above, in the case where the iron powder contains other alloying elements, the diffusion rate of boron is lowered to suppress the formation of FeB or Fe ₂ B, so that it may be difficult to have a uniform compound from the surface of the powder to the center. It may also be difficult to change the entire iron powder into a homogeneous compound even when the diameter of the has a too large value. Therefore, in this regard, it may be preferable to use pure iron powder whose iron maximum diameter does not exceed 1000 μm.

The treatment temperature can be maintained at least 850 ℃ for the iron boron, and below the lowest melting temperature of the iron-boron alloy below 1177 ℃ to prevent the formation of a liquid iron-boron compound layer during the boronization process Temperature, for example, 1050 ° C or less.

The treatment time can be carried out in the range of 30 to 600 minutes. If it is less than 30 minutes, sufficient boration treatment of the iron powder may not be performed, and a treatment exceeding 600 minutes may be an unnecessary process since the boration treatment has already reached the saturation stage.

Next, the furnace body 20 is separated and removed from the outer circumferential surface of the retort 10 when it is determined that boronization of the iron powder is completed in the retort 10. Due to the removal of the furnace body 20, the heating part 22 used for heating the retort 10 is removed, and thus the retort 10 may naturally enter the cooling stage. At this time, as the retort 10 is continuously rotated, the powder in the retort 10 may be uniformly cooled.

After the retort 10 is sufficiently cooled, the mixed powder containing the iron-boron compound powder is taken out from the retort 10.

The mixed powder is mixed with the iron-boron compound powder formed by the reaction of the iron powder and the boron feed material powder, and other remaining raw powder and activator powder. Therefore, the step of separating the mixed powder taken out to the iron-boron compound powder and other powder may be further performed. The separation method may be, for example, using a sieve to separate the iron-boron compound powder and other powder from the mixed powder.

As another embodiment for preparing the iron-boron compound powder, a method of using the boron feed gas as the boron feed material instead of the solid powder form may be performed. The boron supply gas is a gas for supplying boron reacting with the iron powder, and may include boron gas or boron compound gas. In this case, the boron compound gas may include any one of B ₂ H ₆ , BF ₃ , BCl ₃ , BI ₃ , BBr ₃ , (CH ₃ ) ₃ B, and (C ₂ H ₅ ) ₃ B.

According to the present embodiment, the iron powder is charged as the raw material 40 in the retort 10. Next, the retort 10 is heated through the furnace body 20 to supply boron supply gas into the retort 10 while maintaining a predetermined temperature range, for example, 850 ° C to 1050 ° C. At this time, the retort 10 may be rotated for a uniform reaction between the iron powder and the boron feeder.

The boron supply gas may be supplied into the retort 10 through a gas pipe (not shown) connected from the gas reservoir (not shown) to the inside of the retort 10. In this case, the boron supply gas may be mixed with the carrier gas and supplied as a mixed gas, and the boron supply gas may have a range of 2 to 40% by volume in the mixed gas.

After stopping the supply of boron gas at the time when it is determined that the reaction between the iron powder and the boron supply gas in the retort 10 is completed, the furnace body 20 is separated from the retort 10 to cool the retort 10. . It can also be cooled while rotating the retort 10 for uniform cooling.

After the cooling is completed, the iron-boron compound powder produced by the reaction of the iron powder from the retort 10 is taken out. In this case, in the case of the present embodiment, since the boron supply material was supplied in the form of a gas, unlike the embodiment described above, the step of separating the iron-boron compound powder and other residual powder may not be further performed.

Hereinafter, experimental examples are provided to facilitate understanding of the present invention. It should be understood, however, that the following examples are for the purpose of promoting understanding of the present invention and are not intended to limit the scope of the present invention.

[Experimental Example 1]

An average particle size of 80-100 # iron powder was prepared by mixing boron carbide (B ₄ C) powder having an average particle size of 120 # or less as a boron feed material and Na ₃ AlF ₆ powder as an activator. At this time, the boron carbide powder in the mixed powder accounted for 10% by weight, Na ₃ AlF ₆ powder accounted for 1% by weight.

The mixed powder thus prepared was charged into the retort 10 of the compound powder production apparatus 100 as shown in FIG. 1, and then the retort 10 was heated to 950 ° C. for 3 hours to boronize the iron powder. During heating, the retort 10 was rotated at 50 rpm.

After the boronation was completed, the furnace body 20 was separated from the outer circumferential surface of the retort 10 and cooled while rotating the retort 10 as shown in FIG. 3. After the cooling was completed, the mixed powder was taken out from the retort 10 and sieved to separate the boronated iron-boron compound powder and the remaining boron carbide powder.

5 shows the results of observing the cross-sectional structure of the iron-boron compound powder prepared by the present experimental example. Referring to Figure 5, it can be seen that the powder is all composed of an iron-boron compound. 6 shows the X-ray diffraction analysis of the powder. Referring to this, it can be seen that Fe ₂ B was formed as an iron-boron compound.

The hardness of the powder was measured with a Vickers hardness tester (load 20g), and showed a high hardness value of HV 1650.

While the present invention has been described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: compound powder manufacturing apparatus 10: retort
20: old body 20a: first partial body
20b: second partial body 21: frame
22: heating part 22a: first heating part
22b: second heating unit 30: door
40: mixed powder 41: FeB compound layer
42: Fe ₂ B compound layer 43: boron solid layer
44: FeB or Fe ₂ B compound layer

Claims (18)

Preparing an iron-boron compound powder having a boron treatment thereon by rotating and heating a retort surrounded by a furnace equipped with a heating unit while mixing the iron powder and the boron feed material powder charged in the retort with each other. ;
Separating and removing the furnace body from the outer circumferential surface of the retort;
Cooling the retort while rotating;
Extracting the mixed powder comprising the iron-boron compound powder and the remaining boron feed material powder from the retort; And
And separating the mixed powder into the iron-boron compound powder and other powder.
The average diameter of the boron feed material powder has a smaller value than the average diameter of the iron powder,
Method for preparing iron-boron compound powder. The method of claim 1, wherein the iron powder comprises pure iron powder. The method of claim 1, wherein the iron powder has a diameter in the range of 10 to 1000 μm. The method of claim 1, wherein the retort is heated at a temperature range of 850 ° C to 1050 ° C. The method of claim 1, wherein the boron feed material comprises boron powder, boron compound powder and ferroboron powder. The method of claim 5, wherein the boron compound powder comprises boron carbide (B ₄ C) powder or boron oxide (B ₂ O ₃ ) powder. The method of claim 5, wherein the iron powder and the boron feed material are reacted after further loading an activator powder into the retort. The method of claim 7, wherein the activator powder comprises any one or more of Na ₃ AlF ₆ , KBF ₄ , AlF ₃ , NaCl, NaF, CaF _2, and NH ₄ Cl. According to claim 7, wherein the boron feed material in the mixed powder of the iron powder, the boron feed material and the activator powder is in the range of 5 to 50% by weight and the activator powder is in the range of 0.5 to 10% by weight, Method for preparing iron-boron compound powder. delete delete delete delete delete A retort which is rotatable and has an internal space for accommodating the mixed powder;
A first partial furnace including a first subframe disposed to surround an upper surface of an outer circumferential surface of the retort, and a first heating unit disposed inside the first subframe; And
And a second subframe including a second subframe disposed to surround a lower surface of an outer circumferential surface of the retort, and a second heating unit disposed inside the second subframe.
The first heating unit and the second heating unit is arranged to surround the outer peripheral surface of the retort,
The first partial furnace and the second partial furnace body is disposed in the vertical symmetry,
The retort is a compound powder manufacturing apparatus formed with a member protruding from the inner surface of the retort to the inner space in order to rotate the mixed powder along the inner surface of the retort during rotation. The apparatus of claim 15, wherein each of the first partial furnace and the second partial furnace can be moved separately. delete The method of claim 1,
Preparing an iron-boron compound powder in which the iron powder is borated;
A first sub-frame including a first subframe disposed to surround an upper surface of an outer circumferential surface of the retort, and a first heating unit disposed inside the first subframe to surround an upper surface of an outer circumferential surface of the retort; A second subframe disposed to surround the lower surface of the outer circumferential surface of the retort, and a second heating unit disposed inside the second subframe and disposed to surround the lower surface of the outer circumferential surface of the retort, the upper and lower parts of the first partial furnace Heating the retort containing the iron powder and the boron feed material powder by a second partial furnace disposed symmetrically; And
A member protruding from the inner surface of the retort to the inner space that can accommodate the iron powder and the boron feed material powder so that the iron powder and the boron feed material powder rotates along the inner surface of the retort when the retort rotates. Rotating the retort is further formed; comprising, iron-boron compound manufacturing method.

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