KR101577328B1 - Micro-sized control parts and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a microcontroller component manufacturing method and a microcontroller component manufactured thereby. In one embodiment, the microcontroller component manufacturing method includes: preparing a preform by injecting a feedstock containing raw material powder and an organic binder; Supercritical degreasing the preform; And sintering the supercritical degreased preform; Wherein when the raw material powder contains zirconium oxide (ZrO ₂ ) and yttria (Y ₂ O ₃ ), the solid phase ratio (S / L) of the feedstock is 50% to 59% (S / L) of the feedstock is 60% to 69%, and the organic binder is 60 to 75% by volume of paraffin wax, when the iron (Fe), nickel (Ni) 20 to 30% by volume of polyethylene (PE) and 5 to 15% by volume of stearic acid.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-

The present invention relates to a microcontroller component and a method of manufacturing the same. More particularly, the present invention relates to a microcontrol part for forming a feedstock having a specific solid phase ratio by applying a binder composition having a specific ratio to a raw material powder containing zirconium oxide or a stainless steel component, followed by supercritical degreasing and sintering .

Planetary gears or planetary gears (planetary gears or epicyclic gears), unlike spur gears that rotate at fixed revolutions around a fixed axis, carrier, and rotates as if the planet rotates and revolves around the sun.

2 shows a generally used planetary gear device. 2, the planetary gear set 200 includes a sun gear 10, a planetary gear 20, a ring gear 30, and a carrier 40 for rotatably supporting the planetary gear 20 The planetary gear device 200 can be arranged in a more compact structure than the spur gear because the power input shaft and the output shaft can be arranged concentrically and the power transmission rate per unit volume is very large, It is possible to transmit power more than several times that of the gear device and to reduce the loads and speeds applied to the gears constituting the planetary gear set 200, And can control the motion of the ring gear 30 by controlling the sun gear 10 or the planetary gears 20a, 20b and 20c, Or a shifting operation, and can realize a large reduction ratio that is difficult to implement with a spur gear device, and is thus usefully used in aircraft, machine tools, power tools, vehicle transmissions, and the like. 2. Description of the Related Art [0002] Recently, with the miniaturization of various electronic products, there has been an increasing demand for micro-parts such as micro-gears. Accordingly, researches for developing a planetary gear device 200 composed of micro- It is a losing situation.

However, such a planetary gear set 200 is complicated in structure and relatively expensive as compared with a planetary gear set, and centrifugal force is generated in accordance with idle motion.

On the other hand, zirconium oxide is a colorless powder which is excellent in mechanical strength and corrosion resistance and is a ceramic material mainly used as a cutting material or a refractory material because of its low coefficient of thermal expansion. Republic of Korea Patent Publication KR 1985-0003377 discloses such a zirconium-alumina _{(ZrO 2 -Al 2 O 3)} , zirconia-spinel (ZrO ₂ -MgAl ₂ O ₄₎ or zirconia-mullite (ZrO ₂ -3Al ₂ O ₃ · 2SiO ₂ ), and a method for producing the same.

In recent years, such a micro-sized planetary gear unit is injected using a powder injection molding (PIM) molding method, which can be said to be a powder molding method combining powder metallurgy technology and injection molding technology in the plastic industry have. In such a metal powder injection method, a feedstock having fluidity capable of injection molding by using an organic binder as a carrier and mixing metals or ceramic powders is prepared and used as a raw material for injection molding. Therefore, it is possible to manufacture a sophisticated product by applying injection molding because of its sufficient fluidity by the organic binder, and it is possible to manufacture a high-density sintered body by using a powdery raw material excellent in sintering property, so that it can be applied in various fields Do.

In this metal powder injection step, the feedstock is prepared as described above, injection-molded using an injection molding machine, debinded to remove the binder, and then sintered to produce precision parts. Since the degreasing process is a process for removing an unnecessary organic binder in the sintering process, the sintering process greatly influences the quality and productivity of the sintered product. Therefore, studies for increasing the degreasing efficiency have been actively conducted.

The present degreasing methods include heating degreasing, solvent degreasing, and catalyst degreasing. The double degreasing method has disadvantages in terms of economical efficiency because it requires a degreasing time of several hours to several hundreds of hours at a high temperature. And organic solvents harmful to human body.

In addition, the above-described metal powder injection molding method has a problem that the degreasing process is prolonged when the micro-assembly is manufactured, and deformation, cracking, and mechanical properties are deteriorated in the degreasing and sintering process.

It is an object of the present invention to provide a method of manufacturing a microcontroller component for use in a control component application.

Another object of the present invention is to provide a microcontrol part manufacturing method which is superior in mechanical strength, hardness, heat resistance and corrosion resistance to cast parts, and has excellent moldability.

It is still another object of the present invention to provide a method of manufacturing a microcontrol part capable of preventing defects such as deformation and cracks during a degreasing process.

Another object of the present invention is to provide a method of manufacturing a microcontroller part advantageous in terms of process time and energy.

It is still another object of the present invention to provide a microcontroller component manufactured by the microcontroller component manufacturing method.

One aspect of the present invention relates to a method of manufacturing a microcontroller component. In one embodiment, the microcontroller component manufacturing method includes: preparing a preform by injecting a feedstock containing raw material powder and an organic binder; Supercritical degreasing the preform; And sintering the supercritical degreased preform; Wherein the raw material powder comprises zirconium oxide (ZrO ₂ ) and yttria (Y ₂ O ₃ ), the solid phase ratio (S / L) of the feedstock is 50% to 59% Is characterized by containing 60 to 75% by volume of paraffin wax, 20 to 30% by volume of polyethylene (PE) and 5 to 15% by volume of stearic acid.

In another embodiment of the present invention, the microcontroller component manufacturing method includes the steps of: preparing a preform by injecting a feedstock containing raw material powder and an organic binder; Supercritical degreasing the preform; And sintering the supercritical degreased preform; (S / L) of the feedstock is 60% to 69%, and the organic binder is a mixture of iron (Fe), nickel (Ni) and chromium (Cr) 60 to 75% by volume of paraffin wax, 20 to 30% by volume of polyethylene (PE) and 5 to 15% by volume of stearic acid.

In one embodiment, the raw material powder is selected from the group consisting of Fe, Cr, Ni, Nb, Si, Mn, Cob, Cu and Molybdenum Mo).

In another embodiment, the raw material powder comprises at least one material selected from the group consisting of Fe, Cr, Ni, Mn, Mo, P, S, .

In one embodiment, the average particle size of the raw material powder is 0.1 탆 to 10 탆, and the surface area is 3 m 2 / g to 10 m 2 / g.

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In one embodiment, the injection is performed at a cylinder temperature of 100 ° C to 150 ° C, an injection pressure of 180 to 250 bar, and an injection speed of 20 to 40 mm / sec.

In one embodiment, the preform has a gear shape having a diameter of 300 to 1.5 mm.

In one embodiment, the supercritical degreasing is performed using a supercritical fluid, and the supercritical fluid comprises supercritical carbon dioxide.

Another aspect of the invention relates to a microcontroller component manufactured by the microcontroller component manufacturing method. In one embodiment, the microcontroller component is manufactured by the manufacturing method and is a sun gear or a planet gear for a planetary gear set.

The microcontroller component manufacturing method of the present invention is superior in terms of mechanical strength, hardness, heat resistance and corrosion resistance, and can prevent defects such as deformation and cracks during the degreasing process and is advantageous in view of process time and energy, It may be suitable for use as a micro gear included in a gear device.

Figure 1 shows a schematic flow diagram of the present invention.
2 shows a generally used planetary gear device.
Figure 3 shows a preform produced according to one embodiment of the present invention.
FIG. 4A is an enlarged photograph of a preform according to one embodiment of the present invention, and FIGS. 4B and 4C are enlarged photographs of a preform according to a comparative example of the present invention.
FIG. 5A is an electron micrograph of a microcontrol part according to one embodiment of the present invention, and FIG. 5B is an electron micrograph of a microcontrol part according to a comparative example of the present invention.

One aspect of the present invention relates to a method of manufacturing a microcontroller component. Figure 1 shows a schematic flow diagram of the present invention. Referring to FIG. 1, in one embodiment of the present invention, the micro control component manufacturing method includes: a feedstock manufacturing step; A preform forming step; Supercritical degreasing step; And a sintering step. More specifically, the microcontroller component manufacturing method includes: forming a preform by injecting a feedstock containing a raw material powder and an organic binder; Supercritical degreasing the shaped preform; And sintering the supercritical degreased preform; Step < / RTI >

Hereinafter, the partial micro-control component manufacturing method will be described in detail step by step.

Feedstock manufacturing stage

The above step is a step of kneading the raw material powder and the organic binder to prepare feedstock. The feedstock is a mixture of a raw material powder and an organic binder. The feedstock raw material powder and an organic binder are kneaded to uniformly apply an organic binder to the raw material powder.

In the present invention, the raw material powder may be a conventional material used in the field of metals or ceramics. For example, the raw material powder may contain zirconium oxide (ZrO ₂ ) and yttria (Y ₂ O ₃ ) or may include iron (Fe), nickel (Ni) and chromium (Cr). When the raw material powder as described above is included, the thermal expansion coefficient of the present invention is small and the physical properties such as heat resistance, abrasion resistance, impact resistance and hardness can be excellent.

In one embodiment, the raw material powder may include zirconium oxide (ZrO ₂ ), hafnium oxide (HfO ₂ ), yttrium oxide (Y ₂ O ₃ ), sodium oxide (Na ₂ O), and calcium oxide (CaO) . More specifically, the raw material powder may contain 90 to 95% by weight of zirconium oxide (ZrO ₂ ), 0.1 to 5% by weight of hafnium oxide (HfO ₂ ), 3 to 8% by weight of yttrium oxide (Y ₂ O ₃ ) Na ₂ O) 0.001 ~ 0.5% by weight and may contain calcium (CaO) 0.001 ~ 0.5% by weight of oxide. When included in the above composition range, the thermal expansion coefficient of the present invention is small, and the physical properties such as heat resistance, abrasion resistance, impact resistance and hardness can be excellent.

In one embodiment, the zirconium oxide and yttrium oxide may be included in a weight ratio of 1: 0.02 to 0.2. Within the above range, the thermal expansion coefficient of the present invention is low, and the physical properties such as heat resistance, abrasion resistance, impact resistance and hardness can be excellent.

In another embodiment of the present invention, the raw material powder may include iron (Fe), chromium (Cr), and nickel (Ni). In an embodiment, the raw material powders are selected from the group consisting of Fe, Cr, Ni, Nb, Si, Mn, Cob, Cu, ). More specifically, the raw material powder includes 45 to 75 wt% of iron (Fe), 10 to 30 wt% of chromium (Cr), 8 to 25 wt% of nickel (Ni), 0.5 to 5 wt% of niobium (Nb) 0.1 to 5 wt% of silicon (Si), 0.1 to 3 wt% of manganese (Mn), 0.01 to 0.5 wt% of cobalt (Co), 0.01 to 0.5 wt% of copper and 0.01 to 0.5 wt% of molybdenum (Mo) . When the raw material powder of the above composition is included, physical properties such as thermal expansion coefficient, heat resistance, abrasion resistance, impact resistance and hardness can be excellent.

The average particle size of the raw material powder may be 0.1 탆 to 10 탆. Preferably 0.5 [mu] m to 5 [mu] m. In one embodiment of the present invention, the surface area of the raw material powder may be 3 m 2 / g to 10 m 2 / g. And preferably from 4 m < 2 > / g to 8 m < 2 > / g. When feedstock prepared using the raw powder of the above range is used, excellent fluidity is provided at the time of molding and excellent moldability and high sinterability due to high specific surface area promotes densification during sintering, resulting in high sintering It is possible to manufacture a final product having a high density.

In one embodiment, the organic binder may comprise from 50 to 79% by volume of paraffin wax, from 20 to 40% by volume of polyethylene (PE) and from 1 to 20% by volume of stearic acid. It is possible to produce a preform having an excellent mechanical strength and an excellent degreasing effect in a subsequent process.

The paraffin wax may be included for the purpose of increasing the fluidity of the organic binder. As the paraffin wax, a conventional one can be used. For example, those having a main component of a straight chain paraffinic hydrocarbon CH ₃ (CH ₂ ) _n CH ₃ and having 16 to 40 carbon atoms, and preferably 20 to 30 carbon atoms can be used.

The paraffin wax may be contained in an amount of 50 to 79% by volume based on the total volume of the organic binder. And preferably 55 to 79% by volume. And more preferably 60 to 75% by volume. When it is included in the above-mentioned range, it is excellent in fluidity so that degreasing is easily performed in the degreasing process, and the mechanical strength of the sintered final product can be excellent.

The polyethylene (PE) may be included for the purpose of maintaining the shape of the raw material powder. As the above-mentioned polyethylene, a usual one can be used. For example, low density polyethylene, medium density polyethylene, high density polyethylene, or a mixture thereof may be used, but the present invention is not limited thereto. In one embodiment, low density polyethylene (LDPE) having a weight average molecular weight of 30,000 to 300,000 g / mol and a density of 0.910 to 0.923 g / cm3 may be used. In another embodiment, medium density polyethylene (MDPE) having a weight average molecular weight of 30,000 to 300,000 g / mol and a density of 0.923 to 0.941 g / cm3 may be used. In another embodiment, high density polyethylene (HDPE) having a weight average molecular weight of 30,000 to 500,000 g / mol and a density of 0.941 to 0.965 g / cm3 may be used. When polyethylene having the above-mentioned conditions is used, the feedstock has excellent flowability and easy degreasing can be achieved.

The polyethylene may be contained in an amount of 20 to 40% by volume based on the total volume of the organic binder. Preferably 20 to 35% by volume. And more preferably 20 to 30% by volume. When it is included in the above range, the interval between the raw material powders decreases, and the mechanical strength can be excellent in the sintering step.

The stearic acid may be included for the purpose of enhancing the fluidity of the paraffin wax and improving the tackiness of the raw material powder and the components of the organic binder. The stearic acid used in the present invention may be any conventional one.

The stearic acid may be contained in an amount of 1 to 20% by volume based on the total volume of the organic binder. Preferably 1 to 15% by volume. And more preferably 5 to 15% by volume. When the content is within the above range, the raw material powder and the organic binder component are excellent in adhesiveness and can be easily degreased. In the sintering step, the mechanical strength of the final product is excellent and the shrinkage rate is minimized to prevent shape deformation.

The feedstock may be formed using conventional equipment. For example, a double planetary mixer, a twin screw mixer, a twin cam kneader, a kneader extruder, or the like can be used. Type kneader may be used.

In one embodiment, the raw material powder and the organic binder may be added to a kneader and kneaded at 100 ° C to 150 ° C for 1 hour to 6 hours to form a feedstock. The feedstock prepared as described above may be uniformly granulated to have a size of about 5 mm in diameter using an extruder or the like, or may be granulated using a crusher after being solidified into a mass.

At this time, it is important that the feedstock adjusts the solid ratio (S / L), which is the volume ratio of the raw material powder.

In one embodiment of the present invention, when the feedstock includes zirconium oxide and yttrium oxide, the solid phase ratio of the feedstock may be 50% to 59%. And preferably 52% to 59%. And more preferably 52% to 57%. It is possible to greatly reduce the incidence of defects due to the excellent compatibility with the raw material powder in the above composition range and to improve the viscosity and the fluidity of the feedstock so that the shaping can be easily performed and the shape deformation can be prevented, . When the solid phase ratio of the feedstock is less than 50%, an interval between the raw material powders increases, and an extra organic binder separates the raw powder particles during injection molding, thereby partially forming a non-uniform preform, When the solid phase ratio of the feedstock exceeds 59%, the viscosity is excessively increased and the fluidity is lowered, so that the injection property may be rapidly lowered.

In another embodiment of the present invention, when the raw material powder contains iron (Fe), nickel (Ni) and chromium (Cr), the solid phase ratio of the feedstock may be 60% to 69%. And preferably 62% to 69%. And more preferably 62% to 67%. It is possible to greatly reduce the incidence of defects due to the excellent compatibility with the raw material powder in the above composition range and to improve the viscosity and the fluidity of the feedstock so that the shaping can be easily performed and the shape deformation can be prevented, . When the solid phase ratio of the feedstock is less than 60%, the spacing between the raw material powders increases, so that extra organic binder separates the raw powder particles during injection molding, thereby partially forming a non-uniform preform, When the solid phase ratio of the feedstock exceeds 69%, the viscosity increases excessively and the fluidity is lowered, so that the injection property may be drastically lowered.

Preform production step

The above step is a step of producing the preform by injecting the prepared feedstock.

In one embodiment, the injection may be performed by charging the feedstock into an injection molding machine, followed by injection at a mold temperature of 30 to 60 ° C and a cylinder temperature of 100 to 150 ° C to form a preform having a desired shape. Preferably at a mold temperature of 40 ° C to 50 ° C and a cylinder temperature of 110 ° C to 135 ° C to produce a preform having a desired shape. At this time, the injection pressure can be set to 180 to 250 bar and the injection speed can be set to 20 to 40 mm / sec. Preferably, the injection pressure is 200 bar to 230 bar and the injection speed is 20 to 30 mm / sec. The preform can be easily formed under the above conditions.

Figure 3 shows a preform 100 made according to one embodiment of the invention, and Figure 4a is a photograph of a preform made according to one embodiment of the present invention. 3 and 4A, the preform 100 may have a circular gear shape having protrusions and protrusions along the outer circumferential surface thereof. In this case, the diameter R of the preform 100 is defined as the longest distance of the gear-shaped preform.

In one embodiment, the diameter R of the preform 100 may be 300 [mu] m to 1.5 mm. Preferably from 350 [mu] m to 1 mm. Within the above range, the thermal expansion coefficient of the present invention is small, and the physical properties such as heat resistance, abrasion resistance, impact resistance and hardness can be excellent.

Supercritical degreasing step

This step is a step of supercritical degreasing the prepared preform 100. In the present invention, the organic binder component contained in the formed preform 100 can be removed through supercritical degreasing.

The paraffin wax and stearic acid among the organic binder components can be easily removed without cracking between the particles of the feedstock upon degreasing using the supercritical fluid as described above, The degreasing process can be performed in a short time.

The supercritical degreasing is performed using a supercritical fluid. The fluid used for supercritical degreasing may comprise supercritical carbon dioxide. When the fluid is used, the degreasing speed of the organic binder is excellent, and deformation of the preform 100 can be prevented.

In one embodiment, the supercritical degreasing may remove organic binder components contained in the preform 100 at a temperature of 50 ° C to 100 ° C and a pressure of 100 to 500 bar. Rapid degreasing can be achieved while preventing deformation of the preform 100 under the above conditions.

In one embodiment, the supercritical degreasing may degrease 50 to 90% by weight based on the total weight of the organic binder. Deg.] C, preferably 65 to 90% by weight. More preferably, 70 to 90% by weight of the composition can be degreased. The shape of the preform 100 may be maintained in the above range while being defatted, thereby preventing deformation of the preform 100 in the sintering step.

Sintering step

The above step is a step of sintering the supercritical degreased preform 100 to form a formed body. In one embodiment, the sintering may be performed by stepwise heating. In one embodiment, the sintering is performed at a temperature raising rate of 3 to 5 ° C / min and then a temperature is maintained for 1 to 3 hours after the temperature is raised to 500 ° C to 700 ° C. The sintering is performed at a temperature raising rate of 3 to 5 ° C / , The temperature is maintained for 1 to 3 hours, and then the temperature is raised to 1300 ° C to 1500 ° C at a temperature rising rate of 2 to 4 ° C / min, and then the temperature is maintained for 1 to 4 hours. The organic binder component can be removed while preventing the deformation of the degreased preform 100 when sintering at the stepwise elevated temperature as described above, and the high density of 93 to 99%, preferably 95 to 99% And the molded article to be formed has a low thermal expansion property, so that mechanical strength, heat resistance, and corrosion resistance can be excellent.

In the present invention, the sintering can be carried out in the air, but can also be carried out under vacuum conditions. In one embodiment it may be a 10 ^-1 ~ 10 ^-3 torr. Sintering can be carried out in a vacuum controlled to a range of 10 ^-1 to 10 ^-2 torr. The sintering can be easily performed while maintaining the shape of the degreased molded body under the above conditions.

Another aspect of the invention relates to a microcontroller component manufactured by the microcontroller component manufacturing method. The microcontrolled component manufacturing method is superior in mechanical strength, hardness, heat resistance and corrosion resistance to casting products, and can prevent defects such as deformation and cracks during the degreasing process, and can be advantageous in view of process time and energy.

5A is an electron micrograph of a microcontrol part according to one embodiment of the present invention. Referring to FIG. 5A, the micro-fabrication component may have a circular gear shape having protrusions and protrusions along the outer circumferential surface thereof. In one embodiment, the diameter of the microcontroller may be between 300 μm and 1.5 mm. Preferably from 350 [mu] m to 1 mm. In this range, the coefficient of thermal expansion is small and the physical properties such as heat resistance, abrasion resistance, impact resistance and hardness can be excellent.

The manufactured microcontroller may be suitable for use in micro gears included in the planetary gear set. In one embodiment, the microcontroller component may be a sun gear or a planet gear.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example 1

Manufacture of feedstock and preform

93 wt% of zirconium oxide (ZrO ₂ ), 1.65 wt% of hafnium oxide (HfO ₂ ), 5.33 wt% of yttrium oxide (Y ₂ O ₃ ), 0.01 wt% of sodium oxide (Na ₂ O) %, A raw material powder having a spherical shape and an average particle size of 0.88 μm and a surface area of 5.88 m 2 / g was used, and an organic material containing 70 vol% of paraffin wax, 20 vol% of low density polyethylene and 10 vol% of stearic acid The binder was added to a 1 L capacity kneader and kneaded at 130 캜 to prepare feedstock.

The prepared feedstock was crushed in the form of granules using a crusher, charged into an injection molding machine, and powder injection molded at an injection speed of 25 mm / sec at a mold temperature of 45 ° C, a cylinder temperature of 125 ° C and an injection pressure of 210 bar, A gear-shaped preform having a diameter was prepared. At this time, the solid phase ratio (S / L) of the feedstock was adjusted to 56%.

Degreasing

The prepared preform was put into a supercritical degreasing apparatus and carbon dioxide was used as a supercritical fluid to remove the organic binder component. At this time, the supercritical degreasing condition was performed by contacting the preform at a temperature of 60 to 75 ° C. and a pressure of 120 to 300 bar for 3 hours.

Sintering

The degreased preform was put in a sintering furnace and heated to 600 ° C at a heating rate of 5 ° C / min under atmospheric pressure. The temperature was maintained for 1 hour. After the temperature was elevated to 1000 ° C at a heating rate of 5 ° C / The temperature was maintained, and the temperature was raised to 1400 ° C at a rate of 4 ° C / min. After the temperature was maintained for 3 hours, sintering was performed to produce a microcontroller component.

Example 2

(Fe) 51.19 wt%, chromium (Cr) 25 wt%, nickel (Ni) 20.45 wt%, niobium Nb 1.34 wt%, silicon (Si) 0.99 wt%, manganese (Mn) 0.84 wt% 0.08 wt.% Of copper, 0.07 wt.% Of copper, 0.04 wt.% Of molybdenum and having a shape close to a sphere and having an average particle size of 0.88 μm and a surface area of 5.88 m 2 / g, An organic binder containing 70% by volume of paraffin wax, 20% by volume of low density polyethylene and 10% by volume of stearic acid was fed into a 1 L capacity kneader and kneaded at 130 캜 to prepare feedstock.

The prepared feedstock was crushed in the form of granules using a crusher, charged into an injection molding machine, and powder injection molded at an injection speed of 25 mm / sec at a mold temperature of 45 ° C, a cylinder temperature of 125 ° C and an injection pressure of 210 bar, A gear-shaped preform having a diameter was prepared. At this time, microcontrol parts were prepared by degreasing and sintering in the same manner as in Example 1, except that the solid phase ratio (S / L) of the feedstock was adjusted to 65%.

Comparative Example 1

A microcontroller component was prepared in the same manner as in Example 1, except that the solid phase ratio of the feedstock was adjusted to 43%.

Comparative Example 2

A microcontroller component was prepared in the same manner as in Example 1, except that the solid phase ratio of the feedstock was adjusted to 61%.

Comparative Example 3

The preform was charged into an oven using a jig made of ceramic and 90 deg. C of nitrogen gas was flowed at a rate of 90 deg. C per minute, followed by thermal degreasing at a temperature of 650 deg. C for 30 minutes to remove the binder component. Microcontroller parts were manufactured.

Comparative Example 4

A microcontroller component was prepared in the same manner as in Example 2, except that the solid phase ratio of the feedstock was adjusted to 72%.

Test Example

(1) X-ray analysis: The microcontrol parts manufactured in Examples 1 to 2 and Comparative Examples 1 to 4 were analyzed by X-ray to determine the presence or absence of defects and the results are shown in Table 1 below.

(2) Moldability and surface defects: The moldability at the time of manufacturing the microcontroller parts manufactured in Examples 1 to 2 and Comparative Examples 1 to 4 and the surface defects of the finally produced microcontroller parts were visually observed and evaluated The results are shown in Table 1 below.

Evaluation items X-ray inspection Formability Surface defect Example 1 Good Good none Example 2 Good Good none Comparative Example 1 NG Bad Wrinkles and cracks Comparative Example 2 NG Bad Wrinkles and cracks Comparative Example 3 NG Bad crack Comparative Example 4 NG Bad Wrinkles and cracks

FIG. 4A is an enlarged photograph of the preform produced in Example 1 of the present invention, FIG. 4B is an enlarged photograph of the preform produced in Comparative Example 1, and FIG. 4C is a photograph of the preform .

Referring to FIGS. 4A to 4C and the results of Table 1, the preforms of Examples 1 and 2 having the solid phase ratio of the feedstock according to the present invention exhibited good moldability without surface defects. However, In the case of Comparative Example 1, Comparative Example 2 and Comparative Example 4 in which the solid phase ratio of the feedstock was out of the range of the raw powder of the feedstock, serious surface defects such as part of the preform were not formed.

FIG. 5A is an electron micrograph of the microcontrol part of Example 1, and FIG. 5B is an electron micrograph of the microcontrol part of Comparative Example 3. FIG.

Referring to FIGS. 5A, 5B, and Table 1, the microcontroller according to Example 1 had no surface defect, while the microcontroller according to Comparative Example 3 had a serious surface defect such as cracks Could know.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

10: sun gear 20a, 20b, 20c: planetary gear
30: ring gear 40: carrier
100: preform 200: planetary gear device
R: preform diameter

Claims (10)

Injecting a feedstock containing a raw material powder and an organic binder to prepare a preform;
Supercritical degreasing the preform; And
Sintering the supercritical degreased preform; ≪ / RTI >
The raw material powder of zirconium (ZrO ₂₎ 90 ~ 95% by weight, hafnium (HfO ₂₎ 0.1 ~ 5% by weight, yttrium oxide _{(Y 2 O 3) 3 ~} 8 wt%, sodium (Na ₂ O) 0.001 oxide To 0.5% by weight and calcium oxide (CaO) in an amount of 0.001 to 0.5% by weight,
The solid phase ratio (S / L) of the feedstock is 50% to 59%
Wherein the organic binder comprises 60 to 75% by volume of paraffin wax, 20 to 30% by volume of polyethylene (PE) and 5 to 15% by volume of stearic acid.
delete delete delete 2. The method according to claim 1, wherein the raw material powder has an average particle size of 0.1 to 10 m and a surface area of 3 to 10 m < 2 > / g.
delete The method of claim 1, wherein the injection is performed at a cylinder temperature of 100 ° C to 150 ° C, an injection pressure of 180 to 250 bar, and an injection speed of 20 to 40 mm / sec.
The method of claim 1, wherein the preform has a gear shape with a diameter of 300 to 1.5 mm.
2. The method of claim 1, wherein the supercritical degreasing is performed using a supercritical fluid,
Wherein the supercritical fluid comprises supercritical carbon dioxide.
A process for producing a polyurethane foam, which is produced by the production method of claim 1,
Wherein the micro-control component is a sun gear or a planet gear for a planetary gear set.

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