KR102052592B1 - Manufacturing Of Sintered Silicon Nitride Body With High Thermal Conductivity - Google Patents

Abstract

The present invention relates to a method for producing a high thermal conductivity silicon nitride sintered body, more specifically, xSi ₃ N ₄ -yA ₂ O ₃ -zB ₂ O ₃ (where x, y, z are mol% based on the complete nitriding of Si) And x, y, z> 0, A and B are blended with Si, A ₂ O _{3 ,} and B ₂ O ₃ raw powder to follow the composition formula of rare earth metals selected from the group consisting of Y, Sc, Nd and Yb) Step (S10), mixing the blended raw material powder (S20), molding the mixed raw material powder (S30), nitriding the molded body (S40), and the nitriding. By providing a method for producing a silicon nitride sintered body comprising the step of sintering the molded body (S50), to reduce the amount of oxygen in the sintered body to favor the high thermal conductivity, and to provide a silicon nitride sintered body excellent in thermal and mechanical properties by controlling the sintering conditions do.

Description

Manufacturing Method of Sintered Silicon Nitride Body With High Thermal Conductivity

The present invention relates to a method for producing a high thermal conductivity silicon nitride sintered body, and more particularly, to a method for manufacturing a high thermal conductivity silicon nitride sintered body including a sintering aid suitable for the implementation of high thermal conductivity.

Recently, due to the miniaturization, integration, and large area of electronic packages, the amount of heat generated per unit area is rapidly increasing, and the issue of deterioration of product life and quality due to heat is emerging as an important issue. In some industries, such as power semiconductors, high brightness LED-based lighting, and large displays, which are responsible for power conversion and control, how to effectively dissipate heat is a barrier to technological innovation.

Ceramic substrate materials that exhibit both electrical insulation and high thermal conductivity are suitable as heat sinks in applications such as electric vehicles, laser oscillators, reactors in semiconductor manufacturing devices, and circuit boards in precision mechanical components. Has a low intrinsic thermal conductivity. Aluminum nitride (AlN), which has been developed as a material to replace this, can achieve high thermal conductivity of 200 W / mK or more, but there are problems in that it is vulnerable to low mechanical properties and reactivity with moisture.

Silicon nitride is a representative structural ceramic with high toughness and high strength, and at the same time, a high thermal conductivity material having a thermal conductivity of at least 180 W / mK has been studied for application of high thermal conductivity substrates since the 1990s. However, when measuring the thermal conductivity of a silicon nitride sintered body, the thermal conductivity is often lower than 100 W / mK. The reason is that the amorphous phase with the thermal conductivity of 1 W / mK has a continuous phase of 1 nm grain boundary, and within the silicon nitride crystal. This is because impurities such as oxygen and aluminum are dissolved to cause phonon scattering.

Sintered reaction-bonded silicon nitride (SRBSN), which manufactures the final compact in the nitriding and post-sintering process using silicon as the starting material, compared to conventional sintered silicon nitride (SSN), which is used as the starting material. ) Is known to be advantageous for the expression of high thermal conductivity due to the advantage of reducing the amount of oxygen.

Conventional high thermal conductivity silicon nitride sintering aids mainly consist of a mixing system of rare earth oxides and magnesium oxide. Rare earth oxide is effective for removing oxygen in the mouth because of its high oxygen affinity, and magnesium oxide plays a role of promoting densification and grain growth by lowering the eutectic point and viscosity of the liquid phase.

However, magnesium oxide added as a sintering aid has a problem in that it generates an amorphous grain boundary phase and degrades the thermal conductivity of silicon nitride.

Korea Patent Publication No. 10-0244822 Japanese Laid-Open Patent Publication No. 2003-095747

 H. Hayashi et al., J. Am. Ceram. Soc., 2001, vol. 84, pp 3060  Y. Okamoto et al., J. Mater. Res., 1998, vol 13, pp 3473  M. Kitayama et al., J. Am. Ceram. Soc., 2001, vol. 84, pp 353

In order to solve the above problems of the prior art, the present invention provides a method for producing a high thermal conductivity silicon nitride sintered body to reduce the amount of oxygen in the sintered body to favor high thermal conductivity by performing a sinter-nitriding process using silicon as a starting material. The purpose is to.

An object of the present invention is to provide a silicon nitride sintered body having excellent thermal and mechanical properties by sintering by reaction sintering but controlling composition and sintering conditions.

The present invention for achieving the above object, xSi ₃ N ₄ -yA ₂ O ₃ -zB ₂ O ₃ (where x, y, z is mol%, x, y, z based on the complete nitriding of Si Blending Si, A ₂ O _{3 ,} and B ₂ O ₃ raw powder to follow> 0, A and B is a rare earth metal selected from the group consisting of Y, Sc, Nd and Yb (S10); Mixing the blended raw material powder (S20), molding the mixed raw material powder (S30), nitriding the molded compact (S40), and sintering the nitrided compact ( It provides a method for producing a silicon nitride sintered body comprising a (S50).

In one embodiment of the present invention, A in the composition formula may include Sc. At this time, it is preferable that B of the said composition formula is Y. At this time, it is preferable that y + z> 2 in the composition formula, and more preferably 2 <y + z <7.

In one embodiment of the present invention, the composition formula preferably satisfies y> z.

In one embodiment of the present invention may further comprise MgO in the raw material powder.

According to the present invention, by performing the nitriding-post-sintering process using silicon and rare earth oxides, the amount of oxygen in the sintered body is reduced to have an advantageous effect on the expression of high thermal conductivity.

In addition, the silicon nitride sintered body of the present invention is sintered by the reaction sintering method, it has an effect of excellent thermal and mechanical properties by controlling the composition and sintering conditions.

1 is a flow chart of a method for producing a high thermal conductivity silicon nitride sintered body according to the present invention.
2 is a graph showing a sintering schedule according to the present invention.
3 is a graph showing molding density, nitride density, and nitride rate for each composition according to an embodiment of the present invention.
Figure 4 is a graph showing the XRD pattern for each composition according to an embodiment of the present invention.
5 is a scanning electron microscope (SEM) image of each composition according to an embodiment of the present invention.
6 is a plot showing the thermal conductivity of each composition according to an embodiment of the present invention.
7 is a graph showing the relative density for each composition according to another embodiment of the present invention.
8 is a scanning electron microscope (SEM) image according to another embodiment of the present invention.
9 is a graph showing an average particle diameter according to another embodiment of the present invention.
10 is a graph showing the results of measuring the thermal conductivity according to another embodiment of the present invention.
11 is a graph showing a result of measuring biaxial strength of a silicon nitride sintered compact according to another embodiment of the present invention.
12 is a graph showing a result of calculating a thermal shock resistance (Hasselman FOM) of a silicon nitride sintered compact according to another embodiment of the present invention.

A method of manufacturing a high thermal conductivity silicon nitride sintered body according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only this embodiment to make the disclosure of the present invention complete and to those skilled in the art to fully understand the scope of the invention It is provided to inform you.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart showing a method for producing a high thermal conductivity silicon nitride sintered body according to the present invention.

The thermal conductivity of silicon nitride is affected by the particle size and number of grain boundaries, grain boundaries, oxygen content and porosity in the sintered body. Impurities and pores such as grain boundaries and oxygen in the sintered body may act as a barrier for thermal diffusion to reduce thermal conductivity.

Method for producing a high thermal conductivity silicon nitride sintered body according to the present invention for improving the thermal conductivity is xSi ₃ N ₄ -yA ₂ O ₃ -zB ₂ O ₃ (where, x, y, z is mol %, X, y, z> 0, A and B are Si, A ₂ O _{3 ,} and B ₂ O ₃ raw powder to follow the composition formula of the rare earth metal selected from the group consisting of Y, Sc, Nd and Yb Compounding (S10), mixing the blended raw material powder (S20), molding the mixed raw material powder (S30), nitriding the molded body (S40), and the It provides a method for producing a silicon nitride sintered body comprising the step (S50) of sintering the nitrided molded body.

The manufacturing method of the present invention will be described by dividing each step as follows.

First, a step (S10) of blending Si, A ₂ O _{3 ,} and B ₂ O ₃ raw material powder is performed.

Raw material composition for the production of silicon nitride in the present invention can be formulated in the following formula.

(Composition 1)

xSi ₃ N ₄ -yA ₂ O ₃ -zB ₂ O ₃ , wherein x, y, z are mol%, x, y, z> 0, A and B are from the group consisting of Y, Sc, Nd and Yb Selected rare earth metals)

At this time, the content of Si powder included in the raw material composition may be calculated based on the complete nitriding of Si.

A in Formula 1 includes Sc, and B is preferably Y. At this time, it is preferable that y + z> 2 in the general formula (1), more preferably 2 <y + z <7.

In addition, it is preferable that Formula 1 satisfies y> z.

Si is a starting material for obtaining a silicon nitride sintered body having high thermal conductivity by nitriding and post sintering, and it is preferable that the average particle diameter of Si is 800 to 2000 nm. If the average particle diameter of the Si is less than 800 nm, the thermal conductivity decreases due to an increase in the initial amount of oxygen. If the average particle diameter is more than 2000 nm, the silicon nitride sintered compact after reaction sintering and post sintering may not be formed precisely due to large pores in the molded body.

Then, Si, A ₂ O _{3 ,} and B ₂ O ₃ raw powder are blended to follow the composition of Chemical Formula 1. In addition, MgO may be further included in the raw material powder.

For example, in a _{Si-Y 2 O 3 -Sc 2} O 3 or Si-Y ₂ O ₃ may be of a _{-MgO, Si-Y 2 O 3} -Sc 2 O 3 -MgO as a 4-phase 3-phase Can be configured. In addition, the Si-Y ₂ O ₃ -Sc ₂ O ₃ is Si 92 ~ 97% by weight, Y ₂ O ₃ 1-3 weight percent, and Sc ₂ O ₃ It may be included in 2 to 5% by weight, the Si-Y ₂ O ₃ -MgO is Si 90 to 98% by weight, Y ₂ O ₃ 1 to 6% by weight, and MgO 1 to 4% by weight, the Si-Y ₂ O ₃ -Sc ₂ O ₃ -MgO is Si 89 ~ 97.5% by weight, Y ₂ O ₃ 0.5 to 2 wt%, Sc ₂ O ₃ 1 to 5 weight percent, and MgO It may be included in 1 to 4% by weight.

Then, the step (S20) of mixing the blended raw material powder is performed.

The raw materials are wet mixed by adding anhydrous alcohol and then subjected to high energy milling to prepare a mixture. At this time, the milling is preferably performed for 30 to 120 minutes at 50 ~ 300 rpm.

Next, the step (S30) of molding the mixed raw material powder is performed.

The mixture milled in the step (S20) is first dried at 70 ~ 120 ℃ in a rotary evaporator and then dried again at 70 ~ 120 ℃ temperature in an oven to evaporate the water or alcohol in the mixture, 50 ~ 200 mesh ( The molded body is manufactured by sieving the size of a mesh) and compressing by cold hydrostatic press (CIP) for 50 to 300 MPa and 3 to 10 minutes.

Next, nitriding the molded body (S40) is performed.

The molded body is put into a ceramic tube, and nitriding is performed at 1,300 to 1,600 ° C while injecting nitrogen and hydrogen mixed gas.

The nitrogen and hydrogen are mixed in a volume ratio of 90:10 to 99: 1 and injected into the ceramic tube at a flow rate of 300 to 500 sccm. In addition, the nitriding is performed at 1,300 to 1,600 ° C., but the nitriding reaction is not completed when the temperature is less than 1,300 ° C., and the particle growth is suppressed after post-sintering due to the excessive generation of beta-phase silicon nitride when it is above 1,600 ° C.

Finally, the step of sintering the nitrided molded body (S50) is performed.

The nitrided molded body is sintered in a BN crucible using an Si ₃ N ₄ -BN mixed powder (weight ratio 1: 1) for 1 to 12 hours under a temperature of 1,700 to 2,000 ° C. and 0.9 MPa N ₂ gas pressure.

If the temperature is less than 1,700 ℃, there is a problem that pores are formed in the sintered body, if the temperature exceeds 2,000 ℃ is a problem that silicon nitride (Si ₃ N ₄ ) in the sintered body is decomposed. In addition, when the sintering time is less than 1 hour, there is a problem that grain growth does not occur in the sintered compact, and when the sintered time is greater than 12 hours, the relative density of the sintered compact is reduced, and a problem that the strength decreases.

The present invention also provides a high thermal conductivity silicon nitride sintered body produced by the above production method. The silicon nitride sintered body has an average particle diameter of 0.3 ~ 2 ㎛, and has a thermal conductivity of 70 ~ 120 W / mK. That is, the silicon nitride sintered body of the present invention contains Y ₂ O ₃ -Sc ₂ O ₃ or Y ₂ O ₃ -Sc ₂ O ₃ -MgO to reduce the amount of oxygen in the sintered body to improve thermal conductivity, excellent through a short sintering time Has strength and thermal shock resistance (Hasselman FOM).

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention.

< Example  1>

Si ₃ N ₄ -Y ₂ O ₃ -Sc ₂ O ₃ , Si ₃ N ₄ -Y ₂ O ₃ -MgO, and Si ₃ N ₄ -Y ₂ O ₃ -Sc ₂ O ₃ -MgO-based silicon nitride specimens were prepared. . The molar ratio of Y ₂ O ₃ : Sc ₂ O ₃ is 1: 3, and the content of sintering aid is 2-7 mol% while the molar ratio of (Y ₂ O ₃ + Sc ₂ O ₃ ): MgO is 2: 5. A silicon nitride specimen was prepared by changing.

Si (d ₅₀ = 300 nm, purity 99.99%), Y ₂ O ₃ (purity 99.99%), Sc ₂ O ₃ (purity 99.99%), and MgO (purity 99.99%) were used as starting powders.

Table 1 below is a table summarized the composition of the raw material powder blended in Example 1.

Psalter Si ₃ N ₄ (mol%) Y ₂ O ₃
(mol%) Sc ₂ O ₃
(mol%) MgO
(mol%) Si
(wt%) Y ₂ O ₃
(wt%) Sc ₂ O ₃
(wt%) MgO
(wt%) YS1 98 0.5 1.5 0 96.27 1.32 2.41 0 YS2 96 One 3 0 92.67 2.59 4.74 0 YM1 93 2 0 5 92.31 5.32 0 2.37 YSM1 96.5 0.25 0.75 2.5 96.89 0.67 1.23 1.20 YSM2 93 0.5 1.5 5 93.76 1.35 2.48 2.41

The raw powder of Table 1 was mixed in ethanol and milled with Si ₃ N ₄ balls at 200 rpm for 1 hour. The milled raw powder was dried at a temperature of 80 ℃ in a rotary evaporator and then dried in an oven at 105 ℃ for 24 hours.

The dried powder was screened with 100-mesh sieve and then cold hydrostatically formed at a pressure of 200 MPa using a mold having a diameter of 15 mm. The compression molded article was put into an alumina tube and nitrided at 1,450 ° C while injecting nitrogen and hydrogen mixed gas (95% N ₂ + 5% H ₂ ) at a flow rate of 300 sccm. The nitrided bodies were then sintered for 6 h under a temperature of 1900 ° C. and 0.9 MPa N ₂ gas pressure in a BN crucible using Si ₃ N ₄ -BN mixed powder (weight ratio 1: 1) as the atmosphere powder (see FIG. 2). ).

The relative density of the obtained sintered compact was measured by the Archimedes method and analyzed by X-ray diffraction with Rigaku, D / Max 2500. The microstructure of the sintered body was observed by scanning electron microscope (JEOL, JSM-5800), and the particle size distribution and average particle size were analyzed by image analysis software (Media Cybernetics, Image-Pro).

The thermal conductivity of the sintered body was calculated by measuring the thermal diffusion coefficient of the specimen ground with a thickness of 1 mm using a laser flash equipment (Netzsch, LFA447) and multiplying the heat capacity of the silicon nitride (cp = 0.68 J / gK) and density.

Table 2 below shows the results of the measurement of relative density, average particle diameter, and thermal conductivity.

Psalter Relative density
(%) Average particle diameter
(Μm) Thermal conductivity
(W / mK) YS1 98.08 0.86 76.77 YS2 98.74 1.02 88.82 YM1 96.46 0.63 69.17 YSM1 98.60 0.81 74.06 YSM2 99.12 0.91 79.29

As shown in Table 2, the densification was more than 98% in all except YM1 without Y ₂ O ₃ -Sc ₂ O ₃ mixed. In addition, the average particle diameter represents the size of small grains constituting the matrix. Simultaneous addition of Y ₂ O ₃ -Sc ₂ O ₃ promoted abnormal grain growth and increased the matrix mean particle size. The average particle diameter of YS2 compared to YM1 was about 62% coarse. YSM2 added 5 mol% MgO to the YS1 composition, but the grain growth effect was as small as 6%.

3 is a graph showing molding density, nitride density, and nitride rate for each composition according to an embodiment of the present invention. As shown in FIG. 3, the nitriding rate after nitriding at 1,450 ° C. was 90% or more in all specimens.

Figure 4 is a graph showing the XRD pattern for each composition according to an embodiment of the present invention. As shown in FIG. 4, it was confirmed that residual silicon (Si) did not exist inside the nitride specimen through the XRD pattern. When Y ₂ O ₃ -Sc ₂ O ₃ was added, a (Y, Sc) ₂ Si ₂ O ₇ disilicate phase was formed after nitriding, and an apatite phase was detected when Y ₂ O ₃ -MgO was added. It became.

5 is a scanning electron microscope (SEM) image of each composition according to an embodiment of the present invention. As shown in Figure 5, the SEM microstructure of the sintered body can be seen that the growth of abnormal particles is active as the amount of sintering aid is increased (YS1-YS2, YSM1-YSM2). On the other hand, in the case of YM1 having a similar volume ratio to YS2 and sintering aid, the grain growth was slow, and it was confirmed that the addition of Sc ₂ O ₃ forming a eutectic point at a relatively low temperature was favorable for grain growth.

6 is a plot showing the thermal conductivity of each composition according to an embodiment of the present invention. As shown in FIG. 6, the YS2 composition exhibiting the highest thermal conductivity exhibited an improved thermal conductivity of 28.4% compared to the conventional YM1 composition, and the other compositions also exhibited higher thermal conductivity than YM1. This is because the grain growth was accelerated by the addition of Y ₂ O ₃ -Sc ₂ O ₃ , and the grain boundary area was reduced, and the intragranular defects were effectively removed by dissolution-reprecipitation. In particular, the composition of YS2 improves the thermal conductivity of the whole system by forming grain boundaries having low thermal resistance during sintering, and it is estimated that high thermal conductivity was achieved through simultaneous improvement of grain size and grain boundary characteristics even in reaction sintering. In the case of using the reaction sintering method, the thermal conductivity was improved by about 11% compared to the conventional sintering method (YS2, YM1), which is believed to be improved by reducing the amount of oxygen as reported in the existing literature.

< Example  2>

With the YS1, YS2, and YM1 of Example 1, the characteristics of the silicon nitride sintered compact according to the sintering time were evaluated.

Before the sintering step (S50) was carried out in the same manner as in Example 1, the sintering step (S50) was sintered for 1, 3, 6, 12 hours at 1,900 ℃.

The relative density, average particle diameter, and thermal conductivity according to another embodiment (Example 2) of the present invention are summarized in Table 3.

Psalter Sintering time
(hr) Relative density
(%) Average particle diameter
(Μm) Thermal conductivity
(W / mK) YS1 One 96.0 0.40 43.5 3 99.2 0.64 60.3 6 100.1 0.86 78.4 12 99.0 1.15 114.1 YS2 One 97.4 0.39 73.3 3 99.4 0.80 84.4 6 99.0 1.02 88.8 12 98.6 1.84 114.4 YM1 One 93.3 0.51 50.4 3 98.2 0.61 64.8 6 98.9 0.63 69.2 12 98.2 0.95 105.1

7 is a graph showing the relative density of each composition according to another embodiment of the present invention. As shown in FIG. 7, YS1 and YS2 were able to obtain a relative density of 95.8% or more for 1 hour sintering and densification of 98% or more for 3 or 6 hours, but decreased to 97% for 12 hours, that is, for long time sintering. It was. The densification proceeded slowly to 92.7% when sintered for 1 hour, and the maximum density was obtained when sintering for 3 hours, and the sintered density gradually decreased when sintering for a long time.

8 is a scanning electron microscope (SEM) image according to another embodiment of the present invention, Figure 9 is a graph showing the average particle diameter according to another embodiment of the present invention. 9 was calculated the average particle diameter by image analysis.

As shown in FIGS. 8 and 9, almost no grain growth occurred during sintering for 1 hour, and the microstructure of the YM1 composition was relatively coarse by MgO, which is known to form a liquid phase at low temperature. However, as the sintering time was increased, the grain growth of YS2 proceeded faster and the grain growth was the slowest in YM1 composition. It is believed that the volatile MgO volatilized during high temperature sintering, resulting in a decrease in liquid phase and slow grain growth. On the other hand, in the case of YS2 composition, the grain growth is relatively accelerated because the liquid phase loss is relatively low and the low viscosity eutectic liquid phase is relatively present.

10 is a graph showing the results of measuring the thermal conductivity according to another embodiment of the present invention. As shown in FIG. 10, it can be intuitively expected to obtain high thermal conductivity in the YS2 composition which promotes grain growth, but YS2 showed a significantly higher thermal conductivity even under conditions in which grain growth hardly occurred at 1 hour sintering. The thermal conductivity was higher than that of the YM1 6 hour sintered body. Such high thermal conductivity can be said to be enabled by the YS2 sintering aid to improve the thermal conductivity of the grain boundary as mentioned above. That is, when the grain size is relatively small due to the small grain size, it is considered that the effect of grain boundary characteristics on the overall thermal conductivity is remarkable. When the sintering time is increased to 12 hours, the thermal conductivity difference decreases because the grain boundary ratio decreases, which is affected by the grain characteristics rather than the grain boundary characteristics, and the dissolution-reprecipitation reaction is actively promoted by promoting abnormal grain growth of YS1 and YM1. Because it happened.

11 is a graph showing a result of measuring biaxial strength of a silicon nitride sintered compact according to another embodiment of the present invention. As shown in FIG. 11, in the case of YS1 and YM1, the highest strength value was obtained in the three-hour sintering with improved density, and in the case of YS2, the densification occurred quickly even in the one-hour sintering, and thus, in the one-hour sintered body having the finest grain size, High intensity value was shown. In all the sintered bodies, the strength decreased due to grain growth when sintered for more than 3 hours. Considering the thermal conductivity value of FIG. 10, it was confirmed that the composition of YS2 can realize high thermal conductivity and high strength by short sintering (<3h).

< Example  3>

The thermal shock resistance of the silicon nitride sintered compact according to another embodiment (Example 2) of the present invention was evaluated.

When silicon nitride is used as a substrate, cracks are known to occur due to the accumulation of tensile stress due to the temperature variation of the upper and lower ends and the thermal expansion coefficient difference of the metal joint.

The Hasselman mild thermal shock figure of merit was calculated to evaluate the thermal shock resistance considering the thermal conductivity and strength in the trade-off relationship. The related equation is as follows.

Hasselman FOM  = S (1-ν) κ Of aE

S = strength (MPa)

ν = Poisson's ratio

κ = thermal conductivity (W / mK)

a = thermal expansion coefficient (10-6 / K)

E = Young's modulus (GPa)

Except for strength and thermal conductivity, the values reported in the literature were used (Poisson's ratio = 0.3, thermal expansion coefficient = 3.6 (10 ^-6 / K), Young's modulus = 320 GPa).

12 is a graph showing a result of calculating a thermal shock resistance (Hasselman FOM) of a silicon nitride sintered compact according to another embodiment of the present invention. As shown in FIG. 12, YS1 and YM1 had a low FOM value when sintered for 1 hour and maintained a constant FOM value when sintered for 3 hours or more. However, YS2 showed a substantially high FOM value from the sintered body for 1 hour. In other words, YS2 has a good balance of thermal conductivity and strength at presintering conditions, and has a relatively good thermal shock resistance. YS1 showed higher FOM than YM1 because of its higher thermal conductivity and lower strength. In conclusion, YS2 composition has the advantage of realizing high thermal conductivity and preventing deterioration of mechanical properties even with economical short time sintering process.

Accordingly, the present invention is that the thermal conductivity of silicon nitride sintered body and method for producing sintered silicon nitride, the thermal conductivity reaction typically sintering aid is Y ₂ O ₃ instead of Y ₂ O ₃ -MgO -Sc ₂ O ₃ or Y ₂ O ₃ in through the -Sc ₂ O ₃ -MgO was added to improve thermal conductivity, which was attributed to low volatility, low viscosity Y ₂ O ₃ -Sc ₂ O ₃ eutectic grain growth and grain boundary thermal resistance.

In addition, thermal conductivity is improved through grain growth during long-term sintering, but the strength is lowered. On the other hand, YS2 composition can realize high thermal conductivity even in short-time sintering due to the excellent grain boundary properties, and the sintering conditions that minimize the deterioration of mechanical properties (1 ~ 3 hours), excellent strength and thermal shock resistance (Hasselman FOM) were obtained.

The embodiments described above are merely illustrative of the preferred embodiments of the present invention, the scope of the present invention is not limited to the described embodiments, those skilled in the art within the spirit and claims of the present invention It will be understood that various changes, modifications, or substitutions may be made thereto, and such embodiments are to be understood as being within the scope of the present invention.

Claims (9)

XSi ₃ N ₄ -ySc ₂ O ₃ -zY ₂ O ₃ , where x, y, z are mol%, x, y, z> 0, 2 <y + z <7 Compounding Si, Sc ₂ O ₃ , and Y ₂ O ₃ raw material powder so as to follow the composition formula of y>z;
Mixing the blended raw material powder (S20);
Molding the mixed raw material powder (S30);
Nitriding the molded article (S40); And
Sintering the nitrided molded body (S50); Method of producing a silicon nitride sintered body comprising a. The method of claim 1,
Method of producing a silicon nitride sintered body characterized in that the raw material powder further comprises MgO. delete delete delete delete The silicon nitride sintered body manufactured by the manufacturing method of Claim 1 or 2. The method of claim 7, wherein
The sintered body is a silicon nitride sintered body having an average particle diameter of 0.3 ~ 2 ㎛. The method of claim 7, wherein
The sintered body is a silicon nitride sintered body having a thermal conductivity of 70 ~ 120 W / mK.

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