JP6208512B2 - Ceramic joint - Google Patents

Description

  The present invention relates to a ceramic joined body formed by joining ceramic sintered bodies together.

  Silicon nitride sintered bodies and silicon carbide sintered bodies are used in a wide range of fields because of their high mechanical strength and excellent properties such as heat resistance and corrosion resistance. In recent years, with the increase in size of apparatuses and equipment including members that require such characteristics, there has been a demand for increasing the size and length of the members and further complicating the shape of the members. However, it is difficult to integrally form large, long, and complex shaped bodies, and even if an integral shaped body can be obtained, the ceramic itself is difficult to fire. For this reason, it is difficult to obtain a sintered body having no defects even if it is large, long, or has a complicated shape. In addition, in order to cope with large, long, and complicated shapes, it is necessary to prepare large equipment for molding and firing and equipment that can be processed in a complicated manner. Since the cost is high, it is possible to cope with the increase in size, length, and complexity of the shape of the member by joining a plurality of sintered bodies together.

  Silicon nitride-based sintered bodies and silicon carbide-based sintered bodies are used in a wide range of fields because of their high mechanical strength and excellent properties such as heat resistance and corrosion resistance. In addition, since a member that has been increased in size, lengthened, and complicated in shape by bonding needs to have excellent characteristics, the characteristics are improved by the configuration of the bonding layer.

  For example, in the case of Patent Document 1, the applicant of the present application uses a glass containing aluminum, silicon, yttrium, and lutetium as a main component between the principal surfaces of a pair of plate-like bases made of a silicon nitride-based sintered body. A ceramic joined body having improved thermal conductivity by being joined through a joining layer containing crystals has been proposed.

JP 2010-150048 JP

  In addition, the processing of objects to be processed using equipment and facilities is becoming stricter, and the members constituting the equipment and equipment exceed, for example, 1000 ° C. due to the processing environment of the objects to be processed and the temperature rise during processing. It has been used in an environment that is repeatedly exposed to such high temperatures. However, when a bonded body made of ceramics is used in such an environment, there has been a problem that the bonding strength is lowered due to fluctuations in the composition of the bonding layer from the exposed surface side of the bonding layer. Therefore, a joined body made of ceramics is required to be able to maintain a high joint strength even in an environment that is repeatedly exposed to high temperatures and to be usable for a long period of time.

  The present invention has been devised to satisfy the above-described requirements, and an object of the present invention is to provide a ceramic joined body that can be used for a long time even in an environment that is repeatedly exposed to high temperatures.

In the ceramic joined body of the present invention, the first ceramic sintered body and the second ceramic sintered body are joined via a joining layer made of an oxide containing rare earth elements, silicon, aluminum and magnesium, The content of each component inside the bonding layer in terms of oxide is
Of the total 100% by mass in terms of oxides constituting the components constituting the inside, rare earth elements are 35% by mass or more and 45% by mass or less, silicon is 35% by mass or more and 45% by mass or less, and aluminum is 15% by mass or more. 25% by mass or less, magnesium is 0.1% by mass or more and 1% by mass or less, and the content of the rare earth element inside the oxide is converted into an oxide, and the content of the rare earth element outside the bonding layer is converted into an oxide It is characterized by a large amount.

  According to the ceramic joined body of the present invention, even if it is used in an environment that is repeatedly exposed to high temperatures, the joining strength can be maintained high by suppressing the composition fluctuation outside the joining layer, so that it can withstand long-term use. Reliable.

An example of the ceramic joined body of this embodiment is shown, (a) is a partially cut-out perspective view, and (b) is an enlarged partial cross-sectional view of an A part in (a).

  Hereinafter, an example of the ceramic joined body of the present embodiment will be described.

  1A and 1B show an example of a ceramic joined body according to the present embodiment, in which FIG. 1A is a partially cutaway perspective view, and FIG. 1B is an enlarged partial cross-sectional view of a portion A in FIG.

  In the ceramic joined body 10 shown in FIG. 1, the first ceramic sintered body 1 and the second ceramic sintered body 2 have a joining layer 3 made of an oxide containing rare earth elements, silicon, aluminum and magnesium. The content of the rare earth element in the outer portion 3a of the bonding layer 3 in terms of oxide is greater than the content of the rare earth element in the inner portion 3b of the bonding layer 3 in terms of oxide.

  With the above configuration, the first ceramic sintered body 1 and the second ceramic sintered body 2 become a ceramic joined body 10 that is firmly joined and has high joint strength. Further, since the content of the rare earth element in the outer portion 3a of the bonding layer 3 converted to oxide is larger than the content of the rare earth element in the inner portion 3b of the bonding layer 3 converted to oxide, the outer portion 3a of the bonding layer 3, that is, the bonding A large amount of oxides of rare earth elements having a low vapor pressure are present on the outer edge on the exposed surface side of the layer 3. Therefore, even if it is used in an environment that is repeatedly exposed to high temperatures, the composition fluctuation in the outer part 3a of the bonding layer 3 is small, and the bonding strength is maintained high by suppressing this composition fluctuation, so that it can be used for a long period of time. Thus, the ceramic joined body 10 having high reliability can be obtained.

The external 3a in the bonding layer 3 is a portion within 100 μm inward from the exposed surface (side surface in FIG. 1) of the bonding layer 3, and the internal 3b in the bonding layer 3 is based on the exposed surface. As shown in FIG.

  Then, as to whether or not the bonding layer 3 is made of an oxide containing rare earth elements, silicon, aluminum and magnesium, as shown in FIG. 1, the first ceramic sintered body 1, the bonding layer 3, The cross section of the bonding layer 3 in the cross section when the second ceramic sintered body 2 is cut (hereinafter simply referred to as the cross section) is taken as the measurement surface and confirmed by color mapping using an electron beam microanalyzer (EPMA). Can do. When the rare earth element, silicon, aluminum, magnesium and oxygen are confirmed in the same measurement region, the bonding layer 3 is considered to be made of an oxide containing rare earth element, silicon, aluminum and magnesium.

Further, regarding the content of the rare earth element in terms of oxide in the outer part 3a and the inner part 3b of the bonding layer 3, the content of the rare earth element in each part may be obtained using EPMA, and each may be converted into an oxide. Specifically, when the rare earth element is yttrium, EP
The amount of Y may be obtained by MA and converted to Y ₂ O ₃ .

The rare earth element constituting the bonding layer 3 is preferably selected from yttrium, lutetium, ytterbium and erbium. This is because, for yttrium, yttrium oxide (Y ₂ O ₃ ) powder used as a bonding agent is relatively inexpensive and can form the bonding layer 3 at a low temperature. In addition, lutetium, ytterbium and erbium are elements with a small ionic radius among rare earth elements and have strong bonds with silicon and oxygen, so that phonon transmission is good and the thermal conductivity of ceramic joined body 10 is increased. Because you can.

  In addition, lutetium, ytterbium and erbium have a strong bond with silicon and oxygen, so that lattice vibration due to thermal energy is small and volume expansion due to temperature change is small, so that the thermal shock resistance of the ceramic joined body 10 can be increased. it can. In order to form the bonding layer 3 at a low cost while improving the thermal conductivity and thermal shock resistance, a part of the mass of yttrium may be replaced with lutetium, ytterbium, and erbium with yttrium as a base axis.

  Here, the first ceramic sintered body 1 and the second ceramic sintered body 2 in the ceramic joined body 10 of the example shown in FIG. 1 have lengths in the X direction, the Y direction, and the Z direction, for example, It has a flat plate shape of 400 mm to 1000 mm, 400 mm to 1000 mm, 3 mm to 30 mm.

  The ceramic joined body 10 of the present embodiment may be a rod-like or tubular joined body, a joined body of a flat plate shape and a tubular shape, etc., and joins a ceramic sintered body. The shape shown in FIG. 1 is not limited as long as the structure of the bonding layer 3 is satisfied. Further, the bonding layer 3 in the ceramic bonded body 10 of the example shown in FIG. 1 has a thickness (length in the Z direction) of, for example, 5 μm to 100 μm.

  The first ceramic sintered body 1 and the second ceramic sintered body 2 are composed mainly of, for example, silicon carbide, silicon nitride, silicon carbonitride, boron carbide, boron nitride, aluminum nitride, or aluminum oxide. It is a sintered body. In addition, a main component means the component which contains 70 mass% or more among 100 mass% of all the components which comprise a sintered compact here.

In addition, according to the ceramic joined body 10 of the present embodiment, the content of each component in the inner portion 3b in terms of oxide is 35% of rare earth elements out of a total of 100% by mass in terms of the components constituting the inner portion 3b in terms of oxide. Mass% to 45 mass%, silicon is 35 mass% to 45 mass%, aluminum is 15 mass% to 25 mass%, magnesium is 0.1 mass% to 1 mass%
The content of the external rare earth elements in terms of oxides is preferably 56% by mass or more and 64% by mass or less, out of a total of 100% by mass in terms of oxides of the components constituting the external 3a. .

  When the content of the rare earth element and silicon in the inner 3b in terms of oxide is 35% by mass or more and 45% by mass or less, the rare earth element is dissolved in the three-dimensional network formed by the silicon oxide contained. As a result, the bonding strength can be increased. In addition, since the elasticity of the bonding layer 3 is increased, cracks are hardly generated in the bonding layer 3 even when exposed to high temperatures, so that high bonding strength can be maintained.

  Further, when the content of aluminum converted into an oxide is 15% by mass or more and 25% by mass or less, the liquid phase of the rare earth element oxide and the silicon oxide contained in the bonding layer 3 when exposed to a high temperature. Since separation can be suppressed, the bonding layer 3 is difficult to soften, voids due to the softening are hardly generated, and high bonding strength can be maintained.

Further, when the content of magnesium converted to an oxide is 0.1% by mass or more and 1% by mass or less, magnesium is easily bonded to aluminum and oxygen, and by forming a compound such as magnesium aluminate, bonding of the bonding layer 3 is achieved. Strength can be increased. In addition, even when exposed to high temperatures, compounds such as magnesium aluminate are not easily decomposed, and vaporization due to this decomposition is unlikely to occur, and voids are unlikely to be generated in the bonding layer 3, so that high bonding strength can be maintained. .

  Further, when the content of the rare earth element in the external 3a in terms of oxide is 56% by mass or more and 64% by mass or less, in the external 3a while suppressing composition fluctuations when used in an environment that is repeatedly exposed to high temperatures. It can be set as the joining layer 3 which has high joining strength.

  In addition, the ceramic joined body 10 of the present embodiment has a first ceramic sintered body 1 and a second ceramic sintered body 2 (hereinafter referred to as the first ceramic sintered body 1 and the second ceramic sintered body) on the outside 3a. It may be preferable to have a crystal made of an oxide containing a rare earth element in contact with any of the bonded body 2). When satisfying such a configuration, in the bonding layer 3, the bonded bodies are connected without an amorphous phase (glass) having low thermal conductivity, so that heat transfer between the bonded bodies is good. Thus, the thermal conductivity of the ceramic joined body 10 can be increased.

Here, whether or not the crystal is in contact with any of the objects to be bonded is determined by using, for example, 150 reflected electron images taken with a scanning electron microscope (SEM) using the cross section of the bonding layer 3 as a measurement surface. What is necessary is just to confirm by the magnification of 3000 times or less. Whether the crystal is a crystal made of an oxide containing a rare earth element may be identified and confirmed by measurement using an X-ray diffractometer.

Here, when the rare earth element is yttrium, the crystal made of an oxide containing a rare earth element is, for example, yttrium oxide, YAM whose composition formula is represented by Al ₂ Y ₄ O ₉ , and YAP represented by AlYO _3. YAG represented by Y ₃ Al ₅ O ₁₂ .

When the rare earth element is lutetium, the crystal made of an oxide containing the rare earth element is, for example, expressed by a composition formula of lutetium oxide, Lu ₂ Si ₂ O _7, or Lu ₂ SiO ₅ .

  Further, the ceramic joined body 10 of the present embodiment has a crystal made of an oxide containing a rare earth element and silicon in contact with both the first ceramic sintered body 1 and the second ceramic sintered body 2 on the outside 3a. It is suitable to have. A crystal made of an oxide containing a rare earth element and silicon has good crystal symmetry, and therefore heat transfer between the bonded bodies is further improved when contacting any of the bonded bodies. In addition, the thermal conductivity of the ceramic joined body 10 can be further increased. Here, the crystal of an oxide containing a rare earth element and silicon includes borastite, apatite, disilicate, monosilicate, and the like.

  Note that whether or not the crystal is in contact with any of the objects to be joined and whether or not the crystal is a crystal made of an oxide containing a rare earth element and silicon depends on whether the crystal is made of an oxide containing a rare earth element. It can be performed by the same method as the confirmation method in.

In addition, it is preferable that the crystal made of the oxide containing the rare earth element and the crystal made of the oxide containing the rare earth element and silicon have a columnar shape or a needle shape. Here, the shape being columnar or needle-shaped means that the aspect ratio of the crystal is 3 or more in the cross section of the bonding layer 3. The aspect ratio may be measured in accordance with JIS R 1670-2006.

  In the ceramic joined body 10 of the present embodiment, it is preferable that the joining layer 3 further contains nitrogen. When the bonding layer 3 contains nitrogen, the softening point of the oxide constituting the bonding layer 3 is increased, so that it is difficult to soften even when exposed to a high temperature for a long time, and expansion of the bonding layer 3 due to heat is suppressed. Therefore, even if repeatedly exposed to high temperatures, cracks are unlikely to occur in the bonding layer 3, and high bonding strength can be maintained. In particular, the content of nitrogen in the bonding layer 3 is preferably 1% by mass or more and 5% by mass or less, and the presence / absence and content of nitrogen in the bonding layer 3 are quantitative analysis by EPMA or only the bonding layer 3 Can be confirmed by a nitrogen analyzer.

  Moreover, it is suitable for the joining layer 3 in the ceramic joined body 10 of this embodiment that the thickness of the exterior 3a is thicker than the thickness of the interior 3b. When the thickness of the outer part 3a is larger than the thickness of the inner part 3b, the composition fluctuation when repeatedly exposed to a high temperature can be suppressed, so that the bonding strength can be kept high.

  Further, in the bonding layer 3 in the ceramic bonded body 10 of the present embodiment, it is preferable that the waviness of the bonding interface in the outer 3a is larger than the waviness of the bonding interface in the inner 3b. When satisfying such a configuration, even if a shearing force is applied from the outer side 3a to the inner side 3b of the bonding layer 3, the bonding layer 3 is difficult to peel off. Here, the state in which the waviness is large means that, for example, when the bonding interface in the cross section is viewed, the crystals constituting the second ceramic sintered body enter the bonding layer 3 side, and the bonding layer 3 is the second ceramic sintered. It is in a state of entering the body 2 side.

  In addition, in the cross section as shown in FIG. 1B, the size of the undulation is the summit portion that enters the bonding layer 3 side most in the crystal constituting the second ceramic sintered body 2, and the bonding layer. 3 is represented by the difference from the bottom of the valley that penetrates most deeply into the second ceramic sintered body 2 side, and this difference may be confirmed at a magnification of 2000 times or more and 4000 times or less using SEM.

  In the ceramic joined body 10 of the present embodiment, it is preferable that the joining layer 3 does not include pores. When the bonding layer 3 does not include pores, even if the ceramic bonded body 10 is subjected to thermal shock, cracks starting from the outline of the pores are rarely generated, so that the reliability against thermal shock can be improved. The pores in the bonding layer 3 can be confirmed, for example, at a magnification of 150 to 2000 times using a backscattered electron image taken by SEM.

  Moreover, it is preferable that the relative density of the members to be joined constituting the ceramic joined body 10 of the present embodiment is 95% or more and 99% or less. Here, the relative density of the objects to be joined is obtained by obtaining the apparent density of the ceramic sintered body in accordance with JIS R 1634-1998, and dividing this apparent density by the theoretical density of each ceramic sintered body. Find it.

  Next, an example of the manufacturing method of the ceramic joined body of this embodiment is demonstrated.

First, each powder of rare earth oxide, silicon oxide, aluminum oxide and magnesium oxide is prepared. Here, the content of each component in the bonding layer in terms of oxides, of the total 100% by mass in terms of oxides of the components constituting the interior, 35% to 45% by mass of rare earth elements, silicon To make 35 mass% to 45 mass%, aluminum 15 mass% to 25 mass%, and magnesium 0.1 mass% to 1 mass%, the mass ratio of each powder is 35 masses of rare earth element oxide. % To 45% by mass, silicon oxide to 35% to 45% by mass, aluminum oxide to 15% to 25% by mass, magnesium oxide to 0.1% to 1% by mass
These are weighed and mixed so that the total of these powders is 100% by mass.

  The average particle size of each powder is, for example, 5 to 6 μm for rare earth element oxides, 1 μm or less for silicon oxide, 0.4 to 2 μm for aluminum oxide, and 0.5 to 2 μm for magnesium oxide. The average particle size of the aluminum powder is preferably 0.4 μm to 0.6 μm.

In order to include nitrogen in the bonding layer, for example, silicon nitride powder having an average particle diameter of 0.5 μm to 1.5 μm is added in an amount of 1% by mass to 5% by mass with respect to the total of 100% by mass of the powder described above. And mix.

  Next, together with the organic solvent in which the normal paraffinic hydrophobic organic solvent and the dispersant sorbitan fatty acid ester are mixed at a mass ratio of 10: 1, the above-mentioned mixed powder is put into a stirring deaerator and stirred. -A paste-like bonding agent is obtained by defoaming.

  Next, the 1st ceramic sintered compact and the 2nd ceramic sintered compact which consist of a silicon carbide sintered body produced by the well-known method are prepared as a to-be-joined body. Then, a bonding agent is applied (printed) to any one of the bonding surfaces of the objects to be bonded using a screen plate making whose mesh number defined by the screen SUS mesh standard is # 80 or more and # 400 or less. In particular, the screen plate mesh is preferably # 140 or more and # 180 or less. The application thickness of the bonding agent is, for example, 6 μm or more and 110 μm or less.

  And after joining the joining surfaces of a to-be-joined body, a pressure is applied from the direction perpendicular | vertical to a joining surface. Note that the pressure applied here may be due to the weight of the object to be joined located above the joining surface.

Next, it is heat-treated in a porous carbon heat-treatment container. At this time, it is preferable to perform heat treatment in a state in which pressure is applied from a direction perpendicular to the bonding surface. For example, the surface pressure is preferably 1 KPa or more and 2 KPa or less. Also, the heat treatment condition is 800 in a vacuum atmosphere.
After raising the temperature to 0 ° C., nitrogen is supplied to the inside of the heat treatment container and the temperature rise is continued, and the holding temperature and holding time are 1400 ° C. to 1600 ° C. and 30 minutes to 90 minutes in the nitrogen atmosphere, respectively. And the ceramic joined body of this embodiment can be obtained by passing through such heat processing.

  Here, the reason for using a porous carbon heat treatment vessel is that each of oxides of silicon, aluminum, and magnesium has a higher vapor pressure than oxides of rare earth elements, and is easily volatilized when exposed to high temperatures. By using such a heat treatment container, the content of the rare earth element inside the bonding layer converted to oxide is less than the content of the rare earth element inside the bonding layer converted to oxide. Many ceramic joined bodies can be obtained.

The content of each component in the bonding layer of the ceramic bonded body obtained by the above-described manufacturing method in terms of oxide is the total amount of 100% by mass of the component constituting the oxide in terms of oxide. 35 mass% to 45 mass%, silicon is 35 mass% to 45 mass%, aluminum is 15 mass% to 25 mass%, and magnesium is 0.1 mass% to 1 mass%. And, in order to make the content of the rare earth element outside converted into an oxide, the total constituting 100% by mass of the component constituting the outside converted into an oxide, 56 mass% or more and 64 mass% or less,
A heat treatment container having a relative density of 83% to 86% during heat treatment may be used.

Further, in order to obtain a ceramic joined body having a crystal made of an oxide containing a rare earth element in contact with either the first ceramic sintered body or the second ceramic sintered body outside the joining layer, a cumulative distribution curve is obtained. In this case, a rare earth element oxide powder in which D _{90, which} has a cumulative particle diameter of 90% by mass, is 90% or more of the thickness of the bonding layer, may be used.

In order to obtain a ceramic joined body having a crystal composed of an oxide containing a rare earth element and silicon in contact with both the first ceramic sintered body and the second ceramic sintered body outside the joining layer, A rare earth oxide powder having a D ₉₀ of 90% or more of the thickness of the bonding layer and a silicon oxide powder having an average particle size of 0.5 μm or less may be used.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

  First, rare earth element oxide, silicon oxide, aluminum oxide and magnesium oxide powders were prepared. The types of rare earth element oxide powders are as shown in Table 1.

Then, each powder was weighed so that the mass ratio was 40% by mass of the rare earth element oxide, 39.5% by mass of silicon oxide, 20% by mass of aluminum oxide, and 0.5% by mass of magnesium oxide, and then mixed. Sample No. The 9, _10, Y 2 _{O 3} is 35 wt%, was weighed so _Lu 2 _{O 3} is 5% by mass.

  The average particle size of each powder was 5.5 μm for rare earth oxide, 0.6 μm for silicon oxide, 0.5 μm for aluminum oxide, and 1.2 μm for magnesium oxide.

  Next, the mixed powder is put into a stirring deaerator together with an organic solvent in which a normal paraffinic hydrophobic organic solvent and a sorbitan fatty acid ester as a dispersant are mixed at a mass ratio of 10: 1. A paste-like bonding agent was obtained by foaming.

  Next, a first ceramic sintered body and a second ceramic sintered body made of a silicon carbide sintered body having a thickness of 50 mm □ and a thickness of 3 mm prepared by a known method were prepared. Then, a bonding agent was applied to the bonding surface of the second ceramic sintered body using a screen plate making whose mesh number defined by the screen SUS mesh standard was # 165. At this time, the coating thickness of the bonding agent was 45 μm.

  Next, after matching with the joint surface of the first ceramic sintered body, pressure was applied from a direction perpendicular to the joint surface. Then, it put in the heat processing container made from carbon of the relative density shown in Table 1, and heat-processed.

As heat treatment conditions, after raising the temperature to 800 ° C. in a vacuum atmosphere, nitrogen was supplied to the inside of the heat treatment vessel to continue the temperature rise, and the holding temperature and holding time in the nitrogen atmosphere were 1520 ° C. and 60 minutes, respectively. . Further, heat treatment was performed in a state where a surface pressure of 1.5 KPa was applied to the joint surface. And by the method mentioned above, sample No. 1 to 10 ceramic joined bodies were obtained.

And the thermal cycle test was done using these samples. In this test, a sample was placed in a heat treatment apparatus and subjected to heat treatment for 10 hours at 1250 ° C. in an atmosphere having an oxygen partial pressure containing water vapor of 10 ⁻⁹ MPa. ), The cycle from this heat treatment to cooling is 1 cycle, and after every 10 cycles, the bonding layer was observed at a magnification of 100 times using an optical microscope, and the number of cycles where peeling was first observed. It is shown in Table 1.

Sample No. Prepare another sample of 1 to 10, cut out the cross section as shown in FIG. 1, and using EPMA, the content of rare earth elements outside in oxide equivalent and the content of each component inside in oxide equivalent The amount was determined. The content of the rare earth element inside in terms of oxide is 40% by mass, the content of silicon oxide (SiO ₂ ) is 39.5% by mass, and aluminum oxide (A
The content of l ₂ O ₃ ) was 20% by mass, and the content of magnesium oxide (MgO) was 0.5% by mass, confirming that it was as prepared. Table 1 shows the contents of rare earth elements in terms of oxides on the outside and inside.

  As shown in Table 1, sample no. 1, 3, 5, 7, and 9 are sample Nos. Compared to 2, 4, 6, 8, and 10, the number of times that peeling was first observed in the thermal cycle test was higher. From this result, it is bonded via a bonding layer made of an oxide containing rare earth elements, silicon, aluminum and magnesium. Due to the high content of elements in terms of oxides, the composition fluctuation outside the bonding layer is suppressed even when repeatedly exposed to high temperatures, so that the bonding strength can be kept high, and it can be used over a long period of time. It was found that the ceramic joined body has high reliability and can withstand

  Sample No. 2 was prepared in the same manner as in Example 1 except that the blending amount and the relative density of the heat treatment container used during heat treatment were as shown in Table 2. 11 to 37 ceramic joined bodies were produced.

  In addition, a thermal cycle test was performed in the same manner as in Example 1. Also. In the same manner as in Example 1, the content of the rare earth element in the outside in terms of oxide and the content in the inside of each component in terms of oxide were confirmed. As a result, the content of each component in terms of oxide in each component was as prepared. Table 2 shows the number of cycles in which exfoliation was first observed and the content of rare earth elements in terms of oxides outside and inside.

As shown in Table 2, rare earth elements are 35% by mass or more and 45% by mass or less of the total content of 100% by mass of each component in the interior converted to oxide. , Silicon is not less than 35% by mass and not more than 45% by mass, aluminum is not less than 15% by mass and not more than 25% by mass, magnesium is not less than 0.1% by mass and not more than 1% by mass, and external rare earth elements are converted into oxides The amount is 56% by mass or more and 64% by mass or less out of the total 100% by mass of the components constituting the outside in terms of oxides, so that voids are not easily generated in the bonding layer, maintaining high bonding strength, It turned out that it becomes a ceramic joined body with the high reliability which can endure the use over a period.

Sample No. 1 of Example 1 Sample No. 1 produced by the same method as that produced Sample No. 38, except that a rare earth oxide powder having a particle size of ₉₀ μm in the cumulative distribution curve and a D ₉₀ of 36 μm in the cumulative distribution curve was used. Sample No. 1 produced by the same method as that produced And 39, except that the powder and the average particle diameter of the oxide of a rare earth element of the D ₉₀ of 36μm was used silicon oxide powder of 0.5μm Sample No. Sample No. 1 produced by the same method as that produced 40 and prepared.

  And the presence or absence of the crystal | crystallization which contact | connects both the 1st ceramic sintered compact and the 2nd ceramic sintered compact was confirmed in the exterior of the joining layer. In this confirmation, confirmation was performed at a magnification of 3000 times using a backscattered electron image of the cross section including the bonding layer of each sample photographed by SEM. As a result, sample no. In No. 38, crystals in contact with either the first ceramic sintered body or the second ceramic sintered body were not confirmed. 39 and Sample No. For 40, crystals in contact with both the first ceramic sintered body and the second ceramic sintered body were confirmed.

Next, sample No. 39 and Sample No. For 40, crystals were identified using an X-ray diffractometer. As a result, sample no. The crystal outside the bonding layer of 39 is Y ₂ O ₃ , and sample no. The crystal at 40 was Y ₂ SiO ₇ .

  Next, the thermal conductivity of each sample was measured. As a result, sample no. 39 and Sample No. 40 is sample No. The thermal conductivity is higher than 38. The thermal conductivity of 40 was the highest. As a result, the presence of crystals in contact with both the first ceramic sintered body and the second ceramic sintered body outside the bonding layer can increase the thermal conductivity of the ceramic bonded body. It has been found that the thermal conductivity can be further enhanced by the fact that this crystal is an oxide crystal containing a rare earth element and silicon.

1: First ceramic sintered body 2: Second ceramic sintered body 3: Bonding layer 3a: External 3b: Internal

Claims (5)

The first ceramic sintered body and the second ceramic sintered body are joined via a joining layer made of an oxide containing rare earth elements, silicon, aluminum and magnesium, and each component inside the joining layer. The content in terms of oxides is 35% by mass to 45% by mass of rare earth elements and 35% by mass to 45% by mass of silicon out of a total of 100% by mass in terms of oxides of the components constituting the interior. The aluminum content is 15% by mass or more and 25% by mass or less, and the magnesium content is 0.1% by mass or more and 1% by mass or less . A ceramic joined body having a large content of rare earth elements in the form of oxide. Content in terms oxides of rare earth elements before Kigaibu, claims wherein among the total 100 mass% of the component in terms oxide constituting the outside and equal to or less than 56 to 64 mass% 2. The ceramic joined body according to 1.   2. The crystal according to claim 1, further comprising a crystal made of an oxide containing a rare earth element in contact with both the first ceramic sintered body and the second ceramic sintered body. Item 3. The ceramic joined body according to Item 2.   2. A crystal formed of an oxide containing a rare earth element and silicon in contact with both of the first ceramic sintered body and the second ceramic sintered body is provided on the outside. Or the ceramic joined body of Claim 2.   The ceramic joined body according to any one of claims 1 to 4, wherein the joining layer further contains nitrogen.