TWI759081B - Machinable ceramic composite and method for preparing the same - Google Patents

Abstract

A machinable ceramic composite and a method for manufacturing the same are disclosed, and specifically, the machinable ceramic composite may consist of sialon (SiAlON), boron nitride (BN), zirconia (ZrO₂ ), and yttria (Y₂ O₃ ), wherein 2 wt% to 20 wt% of the sialon, 25 wt% to 48 wt% of the boron nitride, 45 wt% to 55 wt% of the zirconia, and 2 wt% to 10 wt% of yttria are contained.

Description

Machinable ceramic composites and methods of making the same

The present invention relates to a machinable ceramic composite and a method of making the same, and more particularly, to a ceramic composite containing sialon having a coefficient of thermal expansion similar to silicon and having improved mechanical properties and micromachinability and its manufacturing method.

Generally, ceramics exhibit good mechanical and insulating properties as well as good high temperature properties. Because of these properties, ceramics have attracted attention as materials used as components of devices in semiconductor manufacturing equipment, but most ceramics are difficult to process.

The machinability of brittle inorganic materials can be improved by dispersing cleavable ceramic components, such as mica or boron nitride, in a ceramic or glass matrix. Ceramics of this type are often referred to as machinable ceramics.

Machinable ceramics can only be used as components of semiconductor inspection devices if they have sufficient insulating properties, good mechanical properties, and ultra-precision machining properties.

Use probe cards to test electrical properties of semiconductor devices. The machinable ceramic can be used as a guide for the probe card, which is the main component that holds the fine probes. Thermal shrinkage and expansion should be optimized according to temperature. In particular, under high temperature conditions, there should not be a difference in thermal expansion coefficient between the machinable ceramic and the silicon that is the substrate of the semiconductor device, so that the electrode pads and the detection probes of the semiconductor device are precisely aligned with each other, which The detection process can be carried out smoothly.

On the other hand, the existing mica series have high thermal expansion coefficient and low strength, so their use is limited. Also, boron nitride composite ceramics are difficult to sinter, which makes it difficult to manufacture a uniform sintered body.

In addition, the known related art ceramic composites of boron nitride and silicon nitride have excellent mechanical properties and micromachinability, but cannot ensure the machinability of ultrafine pores having a diameter of 35 μm or less.

Here, there are few materials that have a thermal expansion coefficient similar to that of silicon and have the high strength and excellent machinability required for high-precision micromachining, and it is impossible to machine with machinable ceramics known in the related art Ultrafine pores with a diameter of 35 μm or less.

The present invention aims to overcome these problems and other disadvantages. One aspect of the present invention provides a high strength machinable ceramic composite with improved toughness and a method of making the same.

Another aspect of the present invention is to provide a ceramic composite containing sialon having a thermal expansion coefficient similar to silicon and having improved mechanical properties and micromachinability, and a method of making the same.

However, these technical problems are only exemplary, and the scope of the present invention is not limited thereto.

To achieve these and other advantages, and in accordance with the purposes of this specification, as embodied and broadly described herein, there is provided a machinable ceramic composite composed of sialon (SiAlON), boron nitride (BN), Composed of zirconium oxide (ZrO ₂ ) and yttrium oxide (Y ₂ O ₃ ), wherein based on the machinable ceramics, the amount of sialon can be 2 wt % to 20 wt %, and the amount of boron nitride can be 25 wt % % to 48 wt%, the amount of the zirconia may be 45 to 55 wt%, and the amount of the yttrium oxide may be 2 to 10 wt%.

According to an embodiment of the present invention, the Sialon can be represented by the following chemical formula (1), and the Sialon can be composed of silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ ), and aluminum nitride (AlN) , [Chemical formula 1] Si _6-z Al _z O _z N _8-z (0<z≤4.2).

According to an embodiment of the present invention, the average particle size of the sialon may be 1 μm.

According to one embodiment of the present invention, the machinable ceramic composite may have a thermal expansion coefficient of 2.0×10 ⁻⁶ /°C to 5.6×10 ⁻⁶ /°C in the temperature range of -40°C to 400°C, and 200 MPa Flexural strength up to 360 MPa.

To achieve these and other advantages, and in accordance with the purposes of this specification, as embodied and broadly described herein, there is provided a method of making a machinable ceramic composite, which method may include preparing a sialon powder, by mixing Sialon powder, boron nitride (BN), zirconia (ZrO ₂ ) and yttrium oxide (Y ₂ O ₃ ) are used to form the first mixed powder, a slurry containing the first mixed powder is prepared, and the prepared slurry is granulated For granular powder, debinding the granular powder, and performing the first sintering by hot pressing the debonded granular powder.

According to an embodiment of the present invention, preparing the sialon powder may include forming a second mixed powder by mixing silicon nitride, aluminum oxide and aluminum nitride, forming a molded body by molding the second mixed powder, and aligning the mold The body undergoes a second sintering, and the sintered molded body is ground.

According to an embodiment of the present invention, the second mixed powder may contain 56.20 wt % to 96.61 wt % of silicon nitride, 2.42 wt % to 31.24 wt % of alumina, and 0.97 wt % to 12.56 wt % of aluminum nitride.

According to an embodiment of the present invention, the first mixed powder may contain 2 wt % to 20 wt % of sialon powder, 25 wt % to 48 wt % of boron nitride, 45 wt % to 55 wt % of zirconia, and 2 wt% to 10 wt% of yttrium oxide.

According to one embodiment of the present invention as described above, there is the effect of providing a high strength machinable ceramic composite with improved toughness and a method of making the same.

In addition, there is an effect of providing a ceramic composite containing sialon having a thermal expansion coefficient similar to silicon and having improved mechanical properties and micromachinability, and a method of making the same.

There is also the effect of providing a machinable ceramic composite capable of machining ultrafine pores with a diameter of 33 μm, a depth of 300 μm and a positional tolerance within ±5 μm by using carbide tools.

However, these technical problems are only exemplary, and the scope of the present invention is not limited thereto.

Hereinafter, the present invention will be described in detail with reference to specific examples of the present invention and the accompanying drawings. These specific examples are merely illustrative to describe the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these specific examples.

Also, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and in case of conflict, the definitions disclosed in this specification shall prevail.

In order to clearly describe the invention presented in the drawings, parts that are irrelevant to the description are omitted, and like reference numerals are assigned to like parts throughout the specification. Furthermore, when a component "comprises" a certain component, it means that other components may be further included, rather than excluded, unless otherwise specified. Furthermore, the term "unit" described in the specification means a unit or block that receives a specific function.

In each step, an identification code (first, second, etc.) is used for convenience of explanation. Unless the context clearly defines a specific order otherwise, the steps may be performed in a different order than specified.

That is, the steps may be performed in the same order as specified, may be performed substantially concurrently, or the steps may be performed in the reverse order.

Hereinafter, in order to enable those skilled in the art to easily implement the present invention, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

According to an embodiment of the present invention, a machinable ceramic composite may be composed of sialon (SiAlON), boron nitride (BN), zirconia (ZrO ₂ ) and yttrium oxide (Y ₂ O ₃ ), preferably 2 To 20 wt% sialon, 25 to 48 wt% boron nitride, 45 to 55 wt% zirconia and 2 to 10 wt% yttria.

In addition, Sialon is represented by the following Chemical Formula 1, and may be composed of silicon nitride, aluminum oxide, and aluminum nitride. That is, Sialon may contain 56.20 to 96.61 wt % of silicon nitride, 2.42 to 31.24 wt % of aluminum oxide, and 0.97 to 12.56 wt % of aluminum nitride. [Chemical formula 1] Si _6-z Al _z O _z N _8-z (0<z≤4.2)

Specifically, the Z value of Formula 1 may more preferably be in the range of 0.2 to 2.6.

In addition, the machinable ceramic composite may have a thermal expansion coefficient of 2.0×10 ⁻⁶ /°C to 5.6×10 ⁻⁶ /°C and a flexural strength of 200 MPa to 360 MPa in a temperature range of -40°C to 400°C.

Hereinafter, the machinable ceramic composite and the method for making the machinable ceramic composite will be described in detail.

FIG. 1 is a flow chart illustrating a method ( S100 ) for manufacturing a machinable ceramic composite according to an embodiment of the present invention.

1 , the method ( S100 ) for manufacturing a machinable ceramic composite may include: a sialon powder preparation step ( S110 ), a first mixed powder forming step ( S120 ), a slurry preparation step ( S130 ), a The granulation step ( S140 ), the debonding step ( S150 ) and the first sintering step ( S160 ).

The Sialon powder preparation step ( S110 ) is characterized in that Sialon, which is the main material of the machinable ceramic composite, is prepared in powder form, and is composed of silicon nitride, aluminum oxide, and aluminum nitride. A detailed manufacturing method will be described in detail with reference to FIG. 2 . FIG. 2 is a flow chart illustrating a method for manufacturing sialon powder according to an embodiment of the present invention.

2 , the Sialon powder preparation step ( S110 ) may include a second mixed powder forming step ( S112 ), a molded body forming step ( S113 ), a second sintering step ( S114 ), and a grinding step ( S115 ).

First, the second mixed powder forming step ( S112 ) may be a step of mixing silicon nitride, aluminum oxide, and aluminum nitride. Here, the second mixed powder may contain 56.20 to 96.61 wt % of silicon nitride, 2.42 to 31.24 wt % of alumina, and 0.97 to 12.56 wt % of aluminum nitride.

At this time, silicon nitride, aluminum oxide, and aluminum nitride may be in powder form. The average particle sizes of the silicon nitride powder, the aluminum oxide powder and the aluminum nitride are preferably 0.8 μm, 0.5 μm and 1 μm, respectively.

Afterwards, silicon nitride, aluminum oxide and aluminum nitride may preferably be weighed according to the above composition, mixed in dry mixing for 2 hours or more using a high-speed mixer, and then the resultant is sieved.

The molded body forming step ( S113 ) may be a step of molding the second mixed powder. In detail, the second mixed powder can be preferably molded by pressing at a pressure of 200 kgf/cm ² using a mold.

For example, to form a molded body, a graphite mold can be filled with powder and pressed. At this time, the graphite mold may be configured as a cemented carbide mold, and the second mixed powder prepared in the second mixed powder forming step may be filled into the cemented carbide mold, and then pressed in a uniaxial pressing manner. However, the present invention may not be limited to the pressing method.

The second sintering step ( S114 ) may be a step of sintering the molded body. Specifically, the molded body may be sintered in a nitrogen or argon atmosphere at a sintering temperature in the range of 1700° C. to 1900° C. for a sintering time of 30 minutes to 2 hours.

The grinding step ( S115 ) may be a step of grinding the sintered molded body, that is, a step of grinding the completely prepared Sialon molded body into a Sialon powder.

At this time, the sintered molded body can preferably be ground so that the average particle size is within 1 μm. The present invention is not limited to the grinding method. In addition, the sialon powder prepared by the above-mentioned preparation method can preferably be represented by the following formula (1). [Chemical formula 1] Si _6-z Al _z O _z N _8-z (0<z≤4.2)

Specifically, the Z value of Formula 1 may more preferably be in the range of 0.2 to 2.6.

The first mixed powder forming step ( S120 ) may be configured to form a first mixed powder containing the Sialon powder prepared by the Sialon powder manufacturing step ( S110 ).

Specifically, the first mixed powder may contain sialon powder, boron nitride, zirconium oxide, and yttrium oxide.

The amount of the sialon powder may be 2 wt % to 20 wt %, and the average particle size of the sialon powder may preferably be 1.0 μm. At this point, Sialon powder can be included in the machinable ceramic composite to increase strength and toughness. When the content of the sialon powder is less than 2 wt %, the strength may be low. This can cause the hole walls to crack during machining of the pores. In addition, when the content of the sialon powder exceeds 20 wt %, the fine hole machining may not be performed.

In addition, Sialon powder has high fracture toughness compared to silicon nitride, and Sialon powder can improve the machinability of fine pores compared to related art machinable ceramic composites containing silicon nitride. That is, the thermal expansion coefficient and Young's modulus of the machinable ceramic composite can be adjusted by adjusting the composition of the Sialon powder, and thus, the performance of the machinable ceramic composite can be maximized.

The amount of boron nitride may be 25 wt % to 48 wt %, and the average particle size of boron nitride may preferably be 1.0 μm. At this time, boron nitride may be included in the machinable ceramic composite to adjust the thermal expansion coefficient. When the content of boron nitride is less than 25 wt%, the thermal expansion coefficient of the composite may be higher than the target value, and when the content of boron nitride exceeds 48 wt%, the thermal expansion coefficient of the composite may be lower than the target value.

The amount of zirconia may be 45 wt % to 55 wt %, and the average particle size of the zirconia may preferably be 0.3 μm. At this time, zirconia may be contained in the machinable ceramic composite to adjust precision machinability and thermal expansion coefficient. When the content of zirconia is less than 45 wt%, the thermal expansion coefficient of the composite may be lower than the target, and when the content of zirconia exceeds 55 wt%, precision machining cannot be performed.

The amount of yttrium oxide may be 2 wt % to 10 wt %, and the average particle size of yttrium oxide may preferably be 1.0 μm. At this point, yttrium oxide may be included in the machinable ceramic composite so that the composite is densified as a sintering aid. When the content of yttrium oxide is less than 2 wt %, the densification of the composite may be insufficient, and when the content of yttrium oxide exceeds 10 wt %, precision machining cannot be performed due to excess residual liquid.

The slurry preparation step ( S130 ) may be a step of preparing a slurry containing the first mixed powder, in detail, a step of additionally mixing a solvent and a binder with the second mixed powder. Preferably, the slurry can be prepared by placing the powder, solvent and binder together with alumina balls in a ball mill, followed by wet mixing for 24 hours.

In this case, the solvent may preferably contain at least one selected from the group consisting of ethanol, methanol, isopropanol, distilled water, and acetone. In addition, polyvinyl butyraldehyde (PVB)-based adhesive may be preferably used as the adhesive.

The granulation step ( S140 ) may be a step of granulating the slurry to prepare granular powder. In detail, spherical granular powder can be prepared by spray drying the slurry. At this time, the granular powder prepared by spray drying is preferably sieved, and sieving may preferably be performed with 100 meshes.

The debinding step ( S150 ) may be a step of debinding the granular powder. In detail, the binder added during the preparation of the granular powder can be removed through a debinding process. In this case, the debonding temperature may preferably be in the range of 600°C to 700°C, and the debonding time may preferably be 2 hours to 3 hours. Additionally, the debonding step can be performed in a debonding furnace in a nitrogen or argon atmosphere or in a debonding furnace in a vacuum atmosphere.

The first sintering step ( S160 ) may be a step of sintering the debonded granular powder by hot pressing. Specifically, preferably, the debonded granular powder may be filled in a graphite mold and sintered by pressing under a pressure of 25 MPa. During sintering, the sintering temperature may preferably be in the range of 1700°C to 1900°C, and the sintering time may preferably be 30 minutes to 2 hours.

Hereinafter, the present invention will be described in detail through examples and experimental examples. However, the following examples and experimental examples are only illustrative, and the present invention is not limited by the following examples and experimental examples.

Examples and Comparative Examples

<Preparation Example 1> Preparation of Sialon powder

To prepare sialon powder, raw material powder was prepared by dry mixing commercially available silicon nitride powder (containing 1.0 wt% oxygen and 0.2 wt% or less impurity metal elements, with an average particle size of 0.8 μm), which was passed through a high-speed mixer. Alumina (99% purity, 0.5 μm average particle size) and aluminum nitride (99% purity, 1.0 μm average particle size) were mixed by dry mixing for 2 hours, and the resulting mixture was sieved.

After that, the mixed Sialon raw material powder was put into a mold and pressed under a pressure of 200 kgf/cm ² , and then synthesized at a temperature of 1800° C. for 2 hours in a nitrogen atmosphere. The synthesized raw material was ground into a powder having a diameter of 1 μm using a planetary mill.

<Preparation Examples 2 to 4>

Sialon powder was prepared in the same manner as in Preparation Example 1, except that the compositions of the silicon nitride powder, the alumina powder, and the aluminum nitride powder were different.

The detailed composition is shown in Table 1 below.

[Table 1] Z value Silicon Nitride (wt%) Aluminum Nitride (wt%) Aluminium oxide (wt%) Preparation Example 1 0.2 96.61 0.97 2.42 Preparation Example 2 1.0 83.07 4.85 12.08 Preparation Example 3 1.8 69.60 8.72 21.68 Preparation Example 4 2.6 56.20 12.56 31.24

<Example 1> Production of a machinable ceramic composite

The 20 wt % sialon powder prepared in Preparation Example 1 and 25 wt % of commercially available boron nitride powder (h-BN, 99% pure, average particle size of 1.0 μm), 50 wt % oxidized Zirconium powder (average particle size: 0.3 μm) and 5 wt% yttrium oxide powder (purity: 99.9%, average particle size: 1.0 μm) were mixed. Thereafter, in order to make the mixed powder into a slurry, 1 wt% polyvinyl butyraldehyde (PVB) binder and ethanol were added, and mixed through a wet ball milling process.

At this time, in the ball milling process, the problem of compositional non-uniformity is minimized by using a polyethylene tank. In addition, the ball milling process was performed for 24 hours by using alumina balls. Thereafter, a spheroidization operation is performed to dry the mixed raw materials into granular powder. The granulation step was performed by using a spray dryer, and the granulated spherical powder was sieved using a 100-mesh sieve.

After that, debinding was performed at 700° C. for 3 hours under a nitrogen atmosphere to remove the organic binder contained in the prepared powder.

After debonding, firing is performed by hot pressing sintering. The debonded granular powder was filled into a graphite mold, pressed in one direction under a pressure of 25MPa in a nitrogen atmosphere, and kept at 1800°C for 2 hours, thereby obtaining a ceramic of 160 mm × 160 mm × 10 mm Sintered body.

<Examples 2 to 24>

A machinable ceramic composite was prepared in the same manner as in Example 1, except that the compositions of Sialon powder, boron nitride powder, zirconia powder, and yttrium oxide powder were different.

Table 2 below shows the detailed composition and Z value of the Sialon powder in each of Examples 1 to 24.

<Comparative Example 1>

25 wt % of commercially available boron nitride powder, 50 wt % of zirconia powder, and 5 wt % of yttrium oxide from Example 1 were mixed with 20 wt % of commercially available silicon nitride powder to make machinable ceramics Complex. A machinable ceramic composite was prepared and evaluated by the same method as Example 1 except that no sialon powder was included and the composition ratios of these materials were different.

<Comparative Example 2>

30 wt% of commercially available boron nitride powder, 55 wt% of zirconia powder, and 5 wt% of yttrium oxide from Example 1 were mixed with 10 wt% of commercially available silicon nitride powder to make a machinable ceramic Complex. A machinable ceramic composite was prepared and evaluated by the same method as Example 1 except that no sialon powder was included and the composition ratios of these materials were different.

<Comparative Example 3>

36 wt% of commercially available boron nitride powder, 54 wt% of zirconia powder and 5 wt% of yttrium oxide from Example 1 were mixed with 5 wt% of commercially available silicon nitride powder to make machinable ceramics Complex. A machinable ceramic composite was prepared and evaluated by the same method as Example 1 except that no sialon powder was included and the composition ratios of these materials were different.

<Comparative Example 4>

By combining the 20 wt% sialon powder (average particle size of 1 μm, Z value 0.2) prepared in Example 1 through preparation as the main raw material, and 20 wt% of commercially available boron nitride in Example 1 The powder, 55 wt% zirconia, and 5 wt% yttria were mixed to prepare and evaluate a machinable ceramic composite using the same conditions and procedures as in Example 1. The detailed composition is shown in Table 2 below.

<Comparative Example 5>

By combining the 5 wt % sialon powder (average particle size of 1 μm, Z value 0.2) prepared in Example 1 and 20 wt % of commercially available boron nitride in Example 1 as the main raw materials The powder, 70 wt% zirconia, and 5 wt% yttria were mixed to prepare and evaluate a machinable ceramic composite using the same conditions and procedures as in Example 1. The detailed composition is shown in Table 2 below.

[Table 2] z value Main component (wt%) Sialon Boron Nitride Zirconia Yttrium oxide Silicon Nitride Example 1 0.2 20 25 50 5 - Example 2 0.2 10 30 55 5 - Example 3 0.2 5 36 54 5 - Example 4 0.2 5 42 48 5 - Example 5 0.2 2 48 45 5 - Example 6 0.2 5 35 50 10 - Example 7 0.2 5 35 58 2 - Example 8 1.0 20 25 50 5 - Example 9 1.0 10 30 55 5 - Example 10 1.0 5 36 54 5 - Example 11 1.0 5 42 48 5 - Example 12 1.0 2 48 45 5 - Example 13 1.8 20 25 50 5 - Example 14 1.8 10 30 55 5 - Example 15 1.8 5 36 54 5 - Example 16 1.8 5 42 48 5 - Example 17 1.8 2 48 45 5 - Example 18 2.6 20 25 50 5 - Example 19 2.6 10 30 55 5 - Example 20 2.6 5 36 54 5 - Example 21 2.6 5 42 48 5 - Example 22 2.6 2 48 45 5 - Example 23 2.6 5 35 50 10 - Example 24 2.6 5 35 58 2 - Comparative Example 1 0 - 25 50 5 20 Comparative Example 2 0 - 30 55 5 10 Comparative Example 3 0 - 36 54 5 5 Comparative Example 4 0.2 20 20 55 5 - Comparative Example 5 0.2 5 20 70 5 -

<Experimental Example 1> Measurement of Thermal Expansion Coefficient

For the ceramic sintered bodies of Examples 1 to 24 and Comparative Examples 1 to 5, the thermal expansion coefficients in the temperature range of -40°C to 400°C and at room temperature were measured using a thermomechanical analyzer (Thermo Mechanical Analyzer; TMA). The specific volume resistance, the results are shown in Table 3.

<Experimental Example 2> Measurement of Bending Strength

Test pieces were cut out from the ceramic sintered bodies of Examples 1 to 24 and Comparative Examples 1 to 5, and the bending strength of each test piece was measured by a three-point bending test, and the results are shown in Table 3.

<Experimental Example 3> Evaluation of Machinability

3 is a schematic diagram illustrating machined locations and through holes for evaluating machinability according to an embodiment of the present invention.

Specifically, in order to evaluate machinability, a sintered body of 160 mm × 160 mm × 10 mm (machinable ceramic composites 100, 100') was ground to a size of 160 mm × 160 mm × 1 mm, thickness deviation within ±5 μm. As shown in FIG. 3( a ), a hole 140 with a thickness of 300 μm is formed at the vertex 110 , the midpoint 120 and the bottom point 130 in the diagonal direction using a carbide drill with a diameter of 28 μm. At this time, 300 holes were formed by drilling holes in the sintered bodies 100, 100' and then forming pits on the opposite surface.

The diameter of each hole is 33 μm and the depth is 300 μm. Use a non-contact 3D measuring machine to measure the diameter and position accuracy of the obtained through holes. In the "Position Accuracy" column of Table 3, use ○ to indicate that the position accuracy is ±5 μm or less, use △ to indicate that the position accuracy is ±10 μm or less, and use × to indicate that the position accuracy exceeds ±10 the case of μm.

In addition, in the "Aperture" column of Table 3, ○ indicates the case where the machining tolerance of the target diameter of 33 μm is ±1.5 μm or less, and × indicates the case where the machining tolerance exceeds ±1.5 μm. In addition, the machining state was confirmed by observation with an optical microscope.

[table 3] Thermal expansion coefficient (10 ^-6 /℃) Strength(MPa) Specific volume (Ω·cm) location accuracy Aperture Machining status X axis Y axis 33 μm Example 1 5.6 358 2.5× ^10-14 ○ ○ ○ good Example 2 5.5 354 4.6× ^10-14 ○ ○ ○ good Example 3 5.3 339 3.6× ^10-14 ○ ○ ○ good Example 4 4.8 317 4.9× ^10-14 ○ ○ ○ good Example 5 4.5 302 6.9× ^10-14 ○ ○ ○ good Example 6 5.3 298 4.4× ^10-14 ○ ○ ○ good Example 7 5.4 286 2.0× ^10-14 ○ ○ ○ good Example 8 5.6 335 4.4× ^10-14 ○ ○ ○ good Example 9 5.4 350 4.1× ^10-14 ○ ○ ○ good Example 10 5.0 310 5.6× ^10-14 ○ ○ ○ good Example 11 5.1 295 2.5× ^10-14 ○ ○ ○ good Example 12 4.2 241 2.9× ^10-14 ○ ○ ○ good Example 13 5.5 311 7.4× ^10-14 ○ ○ ○ good Example 14 5.5 302 6.3× ^10-14 ○ ○ ○ good Example 15 5.4 254 4.9× ^10-14 ○ ○ ○ good Example 16 5.0 211 9.0× ^10-14 ○ ○ ○ good Example 17 4.9 208 4.8× ^10-14 ○ ○ ○ good Example 18 5.2 315 1.6× ^10-14 ○ ○ ○ good Example 19 5.6 329 5.0× ^10-14 ○ ○ ○ good Example 20 4.9 246 4.6× ^10-14 ○ ○ ○ good Example 21 5.1 257 4.7× ^10-14 ○ ○ ○ good Example 22 4.0 204 4.9× ^10-14 ○ ○ ○ good Example 23 4.3 245 2.0× ^10-14 ○ ○ ○ good Example 24 4.4 251 9.0× ^10-14 ○ ○ ○ good Comparative Example 1 5.8 376 5.0× ^10-14 × × × wall split Comparative Example 2 5.4 381 1.0× ^10-14 × × × hole displacement Comparative Example 3 5.6 364 1.5× ^10-14 △ △ ○ hole displacement Comparative Example 4 6.1 404 10.5× ^10-14 × × × tool damage Comparative Example 5 6.9 380 12.0× ^10-14 × × × tool damage

4 is a scanning electron microscope (SEM) image of a machinable ceramic composite according to an embodiment of the present invention.

FIG. 4 shows the results of observing the machinable ceramic composite produced according to Example 1, and it was confirmed that the mixed powder was sintered to prepare the ceramic composite.

5 shows the results of measuring the thermal expansion coefficient of the machinable ceramic composite according to an embodiment of the present invention, and FIG. 6 is after machining holes in the machinable ceramic composite according to an embodiment of the present invention The observed image, FIG. 7, is the result of measuring the positional accuracy on the X-axis and the Y-axis and the diameter of the hole of the machinable ceramic composite according to an embodiment of the present invention.

First, referring to FIG. 6 , in the machinable ceramic composite manufactured according to Example 1, 300 holes having a diameter of 33 μm and a depth of 300 μm, respectively, were machined. From Figure 6 it can be confirmed that the holes are machined uniformly without breaking the walls.

5, 7 and Table 3, it can be confirmed that the flexural strength of the machinable ceramic composites of Examples 1 to 24 is 200 MPa or more, and the thermal expansion coefficient is 2.0×10 ^-6 /℃ to 5.6×10 ^-6 /℃, similar to the thermal expansion coefficient of silicon.

It was also confirmed that the machinable ceramic composite had excellent machinability since the positional accuracy on both the X-axis and the Y-axis was within ±5 μm, and the hole diameter tolerance was within ±1.5 μm.

In contrast, in Comparative Examples 1 to 3, it was confirmed that when measuring machinability, the positional accuracy exceeded ±5 μm in both the X-axis and the Y-axis. In particular, it was confirmed that when the content of silicon nitride was 10 wt % or more, the positional accuracy on both the X-axis and the Y-axis exceeded ±10 μm, and the hole diameter tolerance also exceeded ±1.5 μm.

In Comparative Examples 4 and 5, it was also confirmed that when a low content of boron nitride was added and a high content of sialon was added, the bending strength was improved, but the thermal expansion coefficient was high, and the positional accuracy of the X axis and the Y axis were both more than ±5 μm.

Furthermore, in Comparative Examples 1 to 5, it was confirmed that wall cracks or hole displacements were generated after machining. It was confirmed that the machinability of the silicon nitride-based machinable ceramic composite of the related art was difficult to ensure the machinability of the ultrafine pores having a diameter of 33 μm or less, and the machinability decreased.

In this way, the toughness of the machinable ceramic composite can be improved by adding sialon with high toughness, thereby minimizing such cracking or displacement during pore machining. Therefore, it was confirmed that a machinable ceramic composite having excellent machinability can be produced. In addition, it was confirmed that boron nitride must be mixed in a predetermined weight percent or more in order to ensure the machinability of the ultrafine holes.

That is, according to one embodiment of the present invention, there is an effect of providing a high-strength machinable ceramic composite with improved toughness and a method of making the same, and there is also providing a machinable ceramic composite that can be The effect of machining an ultrafine hole with a diameter of 33 μm, a depth of 300 μm and a positional tolerance within ±5 μm using a carbide tool.

In this specification, only a few embodiments are shown in various specific examples performed by the inventor, however, the technical idea of the present invention is not limited thereto, and various changes and modifications will be made by those skilled in the art.

100: Sintered body/machinable ceramic composite 100': sintered body/machinable ceramic composite 110: Vertex 120: Midpoint 130: Bottom point 140: Hole S100: Method S110: Sialon powder preparation steps S112: Second mixed powder forming step S113: Molded body forming step S114: Second sintering step S115: Grinding step S120: the first mixed powder forming step S130: Slurry preparation step S140: Granulation step S150: Debonding step S160: First sintering step

[ FIG. 1 ] is a flowchart illustrating a method for producing a machinable ceramic composite according to an embodiment of the present invention. [ Fig. 2 ] is a flow chart illustrating a method for preparing a sialon powder according to an embodiment of the present invention. [ Fig. 3 ] is a schematic diagram illustrating machining positions and through holes for evaluating machinability according to an embodiment of the present invention. [ FIG. 4 ] is a scanning electron microscope (SEM) image of a machinable ceramic composite according to an embodiment of the present invention. [ Fig. 5 ] is a graph illustrating the results of measuring the thermal expansion coefficient of a machinable ceramic composite according to an embodiment of the present invention. [ Fig. 6 ] is an image observed after machining holes in the machinable ceramic composite according to an embodiment of the present invention. [ Fig. 7 ] is a result of measuring the positional accuracy on the X axis and the Y axis and the diameter of the hole of the machinable ceramic composite according to an embodiment of the present invention.

Claims (7)

A machinable ceramic composite consisting of sialon (SiAlON), boron nitride (BN), zirconia (ZrO ₂ ) and yttrium oxide (Y ₂ O ₃ ), wherein the machinable ceramic composite is The amount of the sialon is 2wt% to 20wt%, the amount of the boron nitride is 25wt% to 48wt%, the amount of the zirconia is 45wt% to 55wt%, and the amount of the yttrium oxide is 2wt% to 10wt% %, wherein the sialon is represented by the following chemical formula (1), [chemical formula 1] Si _6-z Al _z O _z N _8-z (0<z

4.2), wherein the Sialon is composed of silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ ) and aluminum nitride (AlN), and wherein the average particle size of the Sialon is 1 μm. The machinable ceramic composite of claim 1, wherein by machining ultrafine pores with a diameter of 33 μm and a depth of 300 μm, the positional accuracy of the machinable ceramic composite can be controlled to less than ±5 μm. The machinable ceramic composite of claim 1, wherein the coefficient of thermal expansion is in the range of 2.0×10 ⁻⁶ /°C to 5.6×10 ⁻⁶ /°C at a temperature in the range of -40°C to 400°C, and the flexural strength in the range of 200MPa to 360MPa. A method of making a machinable ceramic composite as claimed in claim 1, the method comprising: preparing a sialon powder; by mixing the sialon powder, boron nitride (BN), zirconia (ZrO ₂ ) and yttrium oxide (Y ₂ O ₃ ) to form a first mixed powder; preparing a slurry containing the first mixed powder; granulating the prepared slurry to prepare a granular powder; debinding the granular powder; and The first sintering is performed by hot pressing the debonded granular powder, wherein the preparing the sialon powder comprises: forming a second mixed powder by mixing silicon nitride, aluminum oxide and aluminum nitride; by molding the secondly mixing powders to form a molded body; subjecting the molded body to a second sintering; and grinding the sintered molded body, and wherein the Sialon powder has an average particle size of 1 μm. The method of claim 4, wherein the positional accuracy of the machinable ceramic composite can be controlled to less than ±5 μm by machining ultra-fine pores with a diameter of 33 μm and a depth of 300 μm. The method of claim 5, wherein the second mixed powder contains 56.20wt% to 96.61wt% of the silicon nitride, 2.42wt% to 31.24wt% of the alumina, and 0.97wt% to 12.56wt% of the nitrogen Aluminum. The method of claim 4, wherein the first mixed powder contains 2wt% to 20wt% of the sialon powder, 25wt% to 48wt% of the boron nitride, 45wt% to 55wt% of the zirconia, and 2wt% to 20wt% 10 wt% of the yttrium oxide.

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