KR20140071279A - Bonded ceramic and process for producing same - Google Patents

Abstract

And the bonding material to be bonded to the silicon nitride ceramics is bonded to each other through a bonding site including the silicon nitride particles and the silicon oxynitride glass. Silicon nitride particles and silicon oxynitride glass are observed in the microstructure of the bonding site. The ratio of the silicon oxynitride glass to the total amount of the silicon nitride grains and the silicon oxynitride glass in the observation field by observation of the two-dimensional cross section is 97: 3 to 60:40. The silicon nitride particles contained on the joint are the main phases.

Description

Technical Field [0001] The present invention relates to a ceramics bonded body,

The present invention relates to a ceramics bonded body and a method of manufacturing the same.

Various methods have been proposed for joining the materials to be bonded made of silicon nitride-based ceramics. For example, (1) a method using a low-melting-point bonding material which is a composition of several kinds of oxide glass, (2) a method in which physical compression bonding such as hot pressing is used when using the same silicon nitride composition bonding material, (3) There has been proposed a method in which the metal is integrated with the base material or a low melting point metal is used as the brazing material.

Specifically, in Patent Document 1, silicon nitride ceramics containing Y ₂ O ₃ and Yb ₂ O ₃ as sintering aids are made of oxynitride glass composed of Y ₂ O ₃ , Al ₂ O ₃ , SiO ₂ and Si ₃ N ₄ And the like.

In Patent Document 2, a silicon nitride rod is inserted into a hole portion of a disc-shaped silicon nitride plate, and a circular joint portion made of CeO ₂ , SrCO ₃ , MgO, Al ₂ O ₃ , SiO ₂ and Si ₃ N ₄ is applied to the substrate and then heated at 1500 DEG C for 1 hour.

Patent Document 3 discloses a method of manufacturing a silicon carbide semiconductor device, which comprises (a) preparing a first raw material containing silicon particles, (b) forming a formed body with a first raw material, and (c) (D) preparing a second raw material such as a first raw material, (e) preparing a slurry with a second raw material, and (f) forming a slurry in the gap between the members to be joined, To form a bonding material; and (g) a step of reacting and sintering the silicon particles in the bonding material by a reaction sintering process similar to that in step (c).

Patent Document 4 discloses a bonding agent mainly composed of glass containing aluminum, silicon, and yttrium on one or both main surfaces of a pair of plate-shaped substrates composed of a silicon nitride sintered body containing lutetium And a step of bonding the main surfaces of the pair of substrates to each other by heat treatment in a non-oxidizing atmosphere by overlapping the main surfaces of the pair of substrates.

Japanese Patent Application Laid-Open No. 5-4876 Japanese Patent Application Laid-Open No. 5-270933 Japanese Patent Application Laid-Open No. 2010-138038 JP-A-2010-150048

As described above, various bonding methods have been proposed. However, when a low melting point bonding material is used, the heat resistance and chemical reactivity of the bonding portion tends to be lowered. When physical compression such as a hot press is used, a special large-sized manufacturing apparatus is required to manufacture a long tubular member. When a bonding material for directly nitriding a silicon metal is used, a silicon metal which is inferior in heat resistance due to lack of nitriding tends to remain in the bonding material.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a ceramics bonded body capable of overcoming various drawbacks of the above-described prior arts and a method of manufacturing the same.

The present invention relates to a ceramics bonded body formed by bonding silicon nitride ceramics bonded materials to each other via a bonding site including silicon nitride particles and silicon oxynitride glass,

The ratio of the silicon nitride particles to the silicon oxynitride glass is 97: 3 to 60:40 in the cross-sectional view of the microstructure of the bonding site,

And the silicon nitride particles contained in the bonding portion are columnar.

Further, the present invention provides a method for producing a ceramics bonded body in which a bonded material of silicon nitride ceramics is bonded to each other through a bonding site including silicon nitride particles and silicon oxynitride glass,

A bonding material containing a mixed powder having a composition capable of forming a bonding site including silicon nitride and silicon oxynitride glass after heating is interposed between the materials to be bonded,

And a method for manufacturing a ceramics bonded body in which the bonded portion is heated while the bonded portion between the bonded materials is pressurized.

The ceramics bonded body of the present invention has a high bonding strength where the bonding site is close to the strength of the material to be bonded. Further, the ceramics bonded body of the present invention can maintain the bonding strength even after it is exposed in a high-temperature oxidizing atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a state in which a material to be bonded is bonded using a bonding material made of a green sheet. Fig.
Figs. 2 (a) and 2 (b) are schematic views showing a state in which the materials to be bonded having the fitting structure are bonded to each other.
3 is a schematic view showing a state in which a material to be bonded is bonded using an inner sleeve.
4 (a) to 4 (d) are schematic views sequentially showing steps of manufacturing a ceramics bonded body by an apparatus suitably used in the production method of the present invention.

Hereinafter, the present invention will be described based on its preferred embodiments. The ceramics bonded body of the present invention is formed by bonding silicon nitride ceramics bonded materials to each other via a bonding site. The two bonded materials to be bonded to each other through the bonding site can take various shapes depending on the intended use of the ceramics bonded object. For example, a hexahedron such as a rectangular parallelepiped or a cuboid, a rod-like body having a smooth end face, a tubular body, or the like. The material to be bonded may be either a solid body or a hollow body. However, it is preferable that the two bonding materials to be bonded have portions that are in surface contact with each other. By having the region, the strength of the ceramics bonded body on the bonded portion can be sufficiently increased.

The two bonding materials bonded through the bonding site may have the same shape or different. Examples of the material to be bonded having the same shape include a shape such as a bar shape or a tubular shape. Examples of the material to be bonded having a different shape include a disk-like shape having a hole portion at the center and a rod-like shape having a cross-sectional shape insertable into the hole portion, as described in the Background Art section.

The two bonded materials bonded to each other through the bonding site may have the same composition insofar as the main material is silicon nitride ceramics or may contain a small amount of a third component such as a sintering auxiliary agent.

The ceramics bonded body of the present invention may be a bonded body of three or more bonded materials depending on its specific use. In this case, two or more bonding sites may exist in the ceramics bonded body.

It is preferable that the ceramics bonded body has a continuous chemical composition and microstructure from the bonding material of which the bonding site is the base material. It is also preferable that the difference in the composition of the material to be bonded on the joining portion and around the joining portion is small. From these points of view, it is advantageous that the bonding site is made of silicon nitride, which is the main material of the bonding material, as the main phase of the crystal phase. It is known that at least one of? -Nitriding silicon and? -Nitriding silicon, which are two kinds of compounds having different crystal structures, exists in the silicon nitride contained on the junction. In addition, there may be a β-sialon which is a material in which a part of Si in β-silicon nitride is substituted with Al and a part of O is substituted with N as a crystal phase on the junction. In summary, at least one of? -Nitrided silicon,? -Nitrided silicon and? -Sialon is present as a crystalline phase on the junction. "Silicon nitride" means at least one of α-silicon nitride, β-silicon nitride and β-sialon, unless otherwise specifically stated in connection with the description of the joints mentioned below.

It is preferable that at least the? -Sialon crystal phase is contained on the joint from the viewpoint of enhancing the strength of the joint. Generally, the ratio of? -Sialon present on the joint is lower than the ratio of silicon nitride present in the region. However, the ratio of? -Sialon or the ratio of silicon nitride present on the joint is not very important in achieving the object of the present invention. The bonding site may also contain a small amount of a third component, for example, a sintering auxiliary agent.

Whether or not the bonding site includes? -Nitriding silicon,? -Nitriding silicon or? -Sialon can be determined by, for example, identifying the crystal phase contained on the bonding portion by x-ray diffraction.

It is advantageous to add an oxide such as glass on the bonding portion so that the glass between the particles of the silicon nitride crystal is filled up because the silicon nitride contained on the bonding portion is a hard sintered material. The glass present between the particles of the silicon nitride crystal is a silicon oxynitride glass in which a part of O in the SiO ₂ glass is contained in the silicon nitride crystal.

It is preferable that the bonding site has a structure in which silicon nitride, which is the main material of the material to be bonded, is used as the main material of the crystal phase, and silicon nitride glass is filled between the crystal grains. As described above, any one or more of? -Nitrided silicon,? -Nitrided silicon and? -Sialon may be present in the silicon nitride crystal. In addition to the silicon oxynitride glass, one or more metal elements commonly used as a sintering aid for silicon nitride such as Al, Y, Mg, Zr, and Yb may be included at the same time. The ratio of the silicon nitride particles to the silicon oxynitride glass is preferably 97: 3 to 60:40, and more preferably 95: 5 to 65:35. By setting the ratio of both of them within this range, a dense joint site tends to be obtained, and the deterioration of the joint site, for example, the strength after holding in the high temperature oxidizing atmosphere for a predetermined time, is hardly deteriorated. The ratio of the silicon nitride grains to the silicon oxynitride glass can be determined, for example, by image analysis of a tissue observation image of a two-dimensional cross-section by a scanning electron microscope (SEM) in which the bonding site is enlarged by about 500 to 5000 times. This ratio can be easily obtained by using, for example, various commercially available computer software for image analysis. By observing the structure of the joints, the difference between the silicon nitride crystal phase and the silicon oxynitride glass can be clearly distinguished.

The ceramics bonded body has one of the characteristics in the microstructure of the bonding site. Specifically, on the junction, columnar particles and spherical particles are observed as crystal grains when the junction is observed under a microscope. As mentioned earlier, the bonding sites are composed of silicon nitride or? -Sialon. These columnar particles and spherical particles are composed of silicon nitride or? -Sialon as a crystal phase. Specifically, the columnar particles mainly contain? -Silicon nitride and? -Sialon as crystalline phases. On the other hand, spherical particles mainly contain? -Silicon nitride as a crystal phase. As a result of studies by the present inventors on the columnar particles and spherical particles, it has been found that the columnar particles mainly comprising? -Nitrided silicon and? -Sialon contribute greatly to the improvement of the strength of the joints. As a result of further studies by the present inventors, it has been found that the balance between the presence of the columnar particles and the spherical particles on the joint greatly affects the bonding strength of the above-mentioned bonding site. Specifically, when the joint portion includes the columnar particles and the spherical particles in a predetermined balance, the joint portion has a high bond strength close to the strength of the material to be bonded. The columnar particles contained on the joint portion mean particles having an aspect ratio (major axis / minor axis) of 2 or more in the structure observation of the cross section of the junction.

The average aspect ratio (long axis / short axis) of the columnar particles is preferably from 2 to 30, more preferably from 2.7 to 20, and most preferably from 2 to 10. The? -Sialon and? -Sialon present on the joint are mainly contained in the columnar particles. , Still more preferably 2.7 to 15. By presenting the columnar particles having such an aspect ratio on the joint, the joint strength and fracture toughness of the joint can be easily increased. The long axis of the columnar particles refers to a line segment having the longest line segment crossing the columnar particles on a two-dimensional image of the columnar particles obtained by microscopic observation of the junction. The short axis means a line segment perpendicular to the major axis and having the shortest line segment crossing the columnar particles. The aspect ratio of the columnar particles can be determined by, for example, performing a tissue observation of a two-dimensional cross section by a scanning electron microscope (SEM) in which the joint portion is enlarged by about 500 to 5,000 times and arbitrarily selecting particles in the observation field, . An arithmetic average of the aspect ratios is obtained for 1000 or more particles having an aspect ratio of 2 or more among the measured particles.

The spherical particles existing on the joint do not need to be a true two-dimensional image of the spherical particles obtained by microscopic observation of the joint site, but may be round enough to be regarded as a source. When the spherical particles are not circular, the aspect ratio (long axis / short axis) of the spherical particles may be less than 2.

The balance between the columnar particles and the spherical particles on the joint is set so that the ratio of the columnar particles to the total amount of the columnar particles and spherical particles in the observation field is preferably 10 to 30%, more preferably 15 to 30% And it was found to be advantageous as a result of examination by the inventors of the present invention. This ratio is calculated by calculating the total area of the two-dimensional area of the spherical particles and the area of the two-dimensional phase of the columnar particles measured by microscopic observation of the junction area enlarged by 500 to 5000 times, dividing the area of the columnar particles by the total area, Respectively. The calculation of this ratio can be carried out, for example, by image analysis of a microscopic observation image of the joint site.

The size of the silicon nitride particles present on the joint depends on the particle size of the mixed powder constituting the bonding material to be described later and is generally equal to or larger than the particle size of the particles constituting the mixed powder. It is preferred that at least 15% by volume is present.

The thickness of the bonding site, that is, the distance between the two bonding materials to be bonded is 50 to 500 μm, particularly 50 to 300 μm, preferably 50 to 100 μm, and at the same time, a bonding region of high bonding strength can be formed .

In order to form the bonding site having the above-described microstructure, for example, the ceramics bonded body of the present invention may be produced by the method described below.

In order to implement the manufacturing method of the present invention, the two silicon nitride ceramics to be bonded are arranged so that their bonding surfaces are opposed to each other. Further, a bonding material having a composition capable of forming a bonding site including silicon nitride particles and silicon oxynitride glass after heating is interposed between the two bonding materials. The bonding material bonded by the two bonding materials is heated to form a bonding site including the silicon nitride grains and the silicon oxynitride glass to bond the materials to be bonded.

It is preferable that the above-mentioned mixed powder includes particles of silicon nitride. It is also preferable to include particles of silicon dioxide (SiO ₂ ) in view of production of silicon oxynitride glass. It is also preferable to include particles of alumina (Al ₂ O ₃ ) from the viewpoint of production of sialon. The ratio of the silicon nitride contained in the mixed powder is generally preferably from 20 to 35% by mass. The proportion of silicon dioxide is generally preferably from 10 to 20% by mass. The ratio of alumina is preferably 5 to 15% by mass. The mixed powder may contain various oxides known as sintering aids such as Y ₂ O ₃ , CaO, MgO, ZrO ₂ and Yb ₂ O ₃ . In particular, Y is an element having a high effect of elongating the silicon nitride crystal grain to the main phase. The various oxides thereof are preferably contained in the mixed powder in an amount of generally 35 to 55 mass%.

It is preferable that the bonding material is such that the silicon nitride particles are excessively contained in the amount of forming the silicon oxynitride glass under the high temperature heating to which the bonding is performed so that a part of the silicon nitride particles remain as solid phase particles in the silicon oxynitride glass. The silicon nitride particles which are not sufficiently dissolved in the silicon oxynitride glass are changed into the columnar particles in the glass during the heating and holding at the time of bonding. When α-silicon nitride is used as the silicon nitride particles as described later, almost all of them are called β-silicon nitride or β-sialon, but when the temperature is low and the holding time is short, a part of α-silicon nitride remains . Although? -silicon nitride remains, the? -silicon nitride has an equiaxed particle shape and is not advantageous for obtaining the strength of the bonding site.

It is preferable that nitrogen is contained in the mixed powder in an amount of 25 equivalent% or more, particularly 25 to 60 equivalent%, more preferably 35 to 55 equivalent%, from the viewpoint of production of the silicon oxynitride glass and from the viewpoint of producing the main phase silicon nitride particles. "Equivalent%" is frequently used when the composition of silicon oxynitride glass is indicated as a notation method considering the valence of ions in glass. The total number of atoms and the number of adducts of the positive and negative ions in the glass is 100%, and the total is 200%.

Particularly, in the present manufacturing method, it is advantageous to use? -Nitriding silicon as the silicon nitride. As mentioned above, it is known that silicon nitride has two kinds of compounds of different crystal structures, i.e.,? -Nitriding and? -Nitriding, and among these two types of silicon nitride,? -Nitriding Is advantageous in that it is possible to easily form a bonding site composed of a microstructure structure including both the aforementioned columnar particles and spherical particles. The reason for this is based on the knowledge of the present inventors that the use of? -Nitriding silicon as silicon nitride can form a junction of dense structure as compared with the case of using? -Nitriding silicon. The use of? -Nitriding silicon as silicon nitride is also based on the knowledge of the inventors of the present invention that even when heated to a low temperature, bonding sites of high bonding strength can be formed as compared with the case of using? -Nitriding silicon. However, in the present invention, the use of? -Nitriding silicon as silicon nitride does not interfere.

In the present manufacturing method, as the mixed powder used for forming the bonding site, those having an average particle size of preferably 0.4 to 5.0 탆, more preferably 0.4 to 3.0 탆, still more preferably 0.4 to 2.0 탆, Do. When the mixed powder having an average particle diameter within this range is used, the fluidity of the mixed powder is appropriately increased when the bonded portion is formed by heating to exhibit good wettability, so that the mixed powder in the flowing state is sufficiently It has been found out that the occurrence of gaps is reduced by spreading evenly. When the mixed powder having a particle diameter smaller than the range of the average particle diameter is used, the fluidity of the mixed powder is not sufficiently increased and the wettability may be low. If the mixed powder having a larger diameter than the average particle diameter is used, densification of the joint portion is not sufficient and the strength may not be obtained.

The average particle size of the mixed powder is measured using, for example, a particle size distribution measuring device by laser diffraction. In order to set the average particle size of the mixed powder to the above-mentioned range, the mixed powder may be subjected to a treatment such as grinding with a mill or the like using a ceramic ball or the like as a medium.

The excess silicon oxynitride glass contained on the joint is diffused into the material to be bonded under high-temperature heating for joining. Further, the crystal phase of? -Nitrided silicon or? -Sialon formed on the junction by high-temperature heating is preferable from the viewpoint of obtaining the strength of the bonding site by forming the columnar particles by stretching and ingrowing by heating and holding at high temperature at the time of bonding. It is effective to increase the heating temperature or to increase the holding time in order to reduce the difference in the composition of the material to be bonded on the joining portion and around the joining portion and to cause the growth of the 棺 -syphonitride or 棺 -sialon columnar particles . On the other hand, silicon nitride or silicon oxynitride glass is decomposed and evaporated at a high temperature, which occurs remarkably when it exceeds 1750 DEG C in an atmospheric nitrogen atmosphere. In addition, in order to make the bonding failure difficult to occur at the time of joining, and to complete the joining in a short time, it is effective to apply pressure mechanically in a direction perpendicular to the joining surfaces of the joining materials so that the joining material and the joining material are in close contact with each other.

The mixed powder used for forming the bonding site can be mixed with a liquid such as water or an organic solvent to prepare a slurry having a predetermined concentration and the slurry can be applied to the bonding surface of the material to be bonded. Alternatively, a green sheet may be formed from the slurry, and the green sheet may be disposed on the bonding surface of the material to be bonded. It is advantageous to use a green sheet from the viewpoints of easiness of work, certainty of arrangement, and the like, and from the viewpoint of forming a joint portion of uniform thickness. For example, as shown in Fig. 1, when the joining material 2 made of mixed powder is interposed between the end faces of the bonded materials 1a and 1b made of tubular bodies of the same shape with their end faces opposing to each other, A circular green sheet can be used.

2 (a) and 2 (b), when the two bonded materials 1a and 1b having a long shape in one direction, such as a tubular body or a rod, are bonded to each other, It is preferable that the end faces of the bonded materials 1a and 1b are brought into contact with each other when the end faces are brought into contact with each other so that the positions of the axial centers of the bonded materials 1a and 1b are aligned. Specifically, as shown in Fig. 2 (a), the end surface 11a of one bonding material 1a is tapered and the other end surface 11b of the bonding material 1b is tapered It is possible to form a pillar bowl having an inclination corresponding to the inclination angle of the pillar. As shown in Fig. 2 (b), the cross-section 11a of one bonding material 1a is formed into a stepped shape having a convex portion, and the cross-section 11b of the other bonding material 1b is convex It is possible to obtain a shape having a concave portion corresponding to the shape of the portion. 2 (a) and 2 (b), the illustration of the bonding material is omitted.

Further, when the material to be bonded has a long shape in one direction such as a tubular body or a rod body, an inner sleeve for positioning the axial center of the material to be bonded may be interposed on the joint portion. This is preferable because it is easy to align the center of the two bonded materials. The inner sleeve also serves as a stiffener for the joint. For example, when the two bonded materials 1a and 1b are tubular members as shown in Fig. 3, the inner sleeve 3 insertable into the bonded materials 1a and 1b is referred to as both bonded materials 1a and 1b, As shown in Fig. The inner sleeve 3 has a tubular or rod-like shape and has a protruding portion 3a on the side of a substantially central region along the long longitudinal direction. The protruding portions 3a are continuously formed over the entire circumferential direction of the inner sleeve 3. The cross section of each of the bonded materials 1a and 1b has a first end face 12 located on the outer peripheral side thereof and a second end face 12 located on the inner peripheral side and lower than the first end face 12 ). When the first end faces 12 of the bonded materials 1a and 1b are brought into contact with each other, a thin portion is formed on the inner wall of the bonded materials 1a and 1b due to the step between the first end face 12 and the second end face 13 . And the projection portions 3a of the inner sleeve 3 are fitted to the thin portions thereof, so that the two bonded materials 1a and 1b can be easily centered. Also in Fig. 3, the illustration of the bonding material is omitted.

The material of the inner sleeve 3 may be the same as or different from the material of the material to be bonded, which is the base material. Further, the inner sleeve 3 may be a material that remains after forming the joint portion by heating, or may be a material that disappears by heating.

The fitting structure shown in Fig. 2 (a) or (b) and the inner sleeve 3 shown in Fig. 3 may be used in combination.

The bonding material disposed between the two bonding materials 1a and 1b is preferably heated at a temperature of 1500 to 1750 ° C, particularly 1550 to 1730 ° C, and more preferably 1600 to 1700 ° C. By heating at a temperature within this range, it is possible to create a bonding site having a dense structure. The heating atmosphere is preferably a nitrogen atmosphere.

The heating time is preferably 0.5 to 12 hours, more preferably 1 to 6 hours, when the heating temperature is within the above-mentioned range. During this time, the difference in the composition of the material to be bonded around the joint portion and the joint portion due to the diffusion of the silicon oxynitride glass is reduced by heating over the period of time, and the balance of the? -Nitride or? So that a bonding site having a composition and structure closer to the material to be bonded can be smoothly formed.

During heating, it is advantageous to press the two bonded materials in contact with each other in the direction in which they face each other. By doing so, a junction having a dense structure can be smoothly formed. From this point of view, the pressure of the pressurizing is preferably set to 0.01 to 5 MPa, particularly 0.1 to 5 MPa, and more preferably 1 to 5 MPa.

It is also preferable to rotate the two bonding materials in contact with each other at the same speed in the same direction as the circumference of the axis perpendicular to the bonding surfaces of the materials to be bonded while heating. This operation is effective when joining elongated bonded materials in one direction in series in the longitudinal direction thereof. By this rotation, sagging of the bonding material under the high temperature under heating due to gravity can be suppressed, so that bending of the bonding body can be prevented. In addition, it is possible to prevent the bonding material from flowing to the lower side of the bonding portion. From the viewpoint of making this effect more conspicuous, the rotation speed is preferably 1 to 5 rpm, particularly 3 to 5 rpm. When the rotation is not performed, the bonding material flows out, and due to the shortage of the bonding material, there is a case that a deficiency of the strength is caused due to lack thereof.

Formation of the joint portion by heating of the bonding material may be completed only by one heating, or may be performed twice or more times as necessary. In general, it is possible to form a bonding site having a satisfactory microstructure by heating only once.

In the ceramics bonded body obtained by the manufacturing method of the present invention, the strength of the bonded portion is close to the strength of the bonded material as the base material. Specifically, in the ceramics bonded body obtained by the manufacturing method of the present invention, the four-point bending strength of the joint portion is preferably 50% or more, more preferably 60% or more, more preferably 50% or more, Or more, and still more preferably 70% or more.

Further, in the ceramics bonded body obtained by the manufacturing method of the present invention, the bonding strength equivalent to that before exposure on the bonding portion is maintained even after the substrate is repeatedly exposed for several hours under the atmosphere of 900 캜 for one hour. Specifically, the four-point bending strength after exposure is preferably not less than 70%, more preferably not less than 80%, still more preferably not less than 85% with respect to the four-point bending strength before exposure (JIS R1601).

Figs. 4 (a) to 4 (d) sequentially show schematically the steps of manufacturing a ceramics bonded body by a device suitably used in the production method of the present invention. The apparatus shown in this drawing is particularly suitably used for joining tubular or rod-shaped materials to be bonded.

First, as shown in Fig. 4 (a), the two bonded materials 1a and 1b to be joined are held by the chuck 20, respectively. So that the two bonded materials 1a and 1b by the chuck 20 are held horizontally. Each of the chucks 20 is provided on the pedestal 21 so as to be slidable on the pedestal 21. When the joining material 2 is disposed between the end faces with the end faces of the materials to be bonded 1a and 1b facing each other with a predetermined distance therebetween, one of the chucks 20 is moved in the direction shown by the arrow in Fig. And the bonding material 2 is sandwiched by the bonding materials 1a and 1b.

When the materials to be bonded 1a and 1b are in the form of, for example, a round tube or a round bar, the outer diameter is preferably 5 to 60 mm, particularly 10 to 45 mm, and more preferably 10 to 30 mm, 1a, 1b). When the materials to be bonded 1a and 1b are in the shape of, for example, round tubes or round bars, they can be bonded even if the upper limit of the length is 2000 mm. There is no limitation on the lower limit of the length, and the shorter the length, the easier the joining.

Then, the material to be bonded (1a, 1b) is rotated around its axis by a rotation mechanism (not shown) provided in the chuck 20 as shown in Fig. 4 (b). With this rotation, the two chucks 20 are moved in the directions indicated by arrows in the drawing, and the contact portions of the two bonded materials 1a and 1b are introduced into the heating furnace 22. At this time, it is advantageous to press the materials to be bonded 1a and 1b in the axial direction to oppose each other so that the bonding material 2 does not fall off.

When the contact portions of the two bonding materials 1a and 1b are introduced into the heating furnace 22, the heating of the heating furnace 22 is continued while the rotation of the materials to be bonded 1a and 1b are continued as shown in Fig. And heats the bonding material 2 located at the contact portion. During heating, rotation of the materials to be bonded (1a, 1b) is continuously performed. During heating, the materials to be bonded (1a, 1b) are pressed in directions opposite to each other in the axial direction thereof. By holding the materials to be bonded (1a, 1b) horizontally and heating them while rotating them around their axes, bonding sites having a desired microstructure can be formed.

When heating is performed at a desired temperature and time to form a desired bonding site, heating by the heating furnace 22 is stopped. However, the rotation of the materials to be bonded 1a and 1b continues even after the heating is stopped. When the heating furnace 22 is cooled to room temperature, the rotation of the bonded materials 1a and 1b is stopped, and the chuck 20 is moved to take out the bonded portion from the heating furnace 22. Thus, a ceramics bonded body is obtained. In order to increase the length of the ceramics junction body, the bonding material 1c is prepared as shown in Fig. 4 (d), and the end surface of the bonding material 1c and the end surface of the bonding material 1b are opposed to each other at a predetermined distance And the bonding material 2 is disposed between both end faces. Thereafter, the same operation as in the above-described operation is carried out to obtain a long ceramics joined body in which the three bonded materials 1a, 1b, and 1c are connected in series along their long longitudinal direction. By repeating the above-described operation, a long ceramic joint body having a desired length can be obtained.

As described above, according to the method shown in Fig. 4, the material to be bonded having a long shape extending in one direction such as a tubular shape or a bar shape can be easily manufactured by a compact facility.

The ceramics bonded body thus obtained can be used as a sintering furnace member such as a heater tube, a protective tube for a thermoelectric pair, a core tube for a rotary kiln, a roller for a roller hearth kiln, Abrasion-resistant mechanical parts such as liners, stirring wing materials, and rollers for conveying steel plates, pipe members for conveying chemicals such as slurries, and the like.

While the present invention has been described based on the preferred embodiments thereof, the present invention is not limited to the above embodiments. For example, in the apparatus shown in Fig. 4, a ceramics bonded body intended to be heated while rotating the bonded materials 1a and 1b around an axis orthogonal to the bonded faces of the bonded materials 1a and 1b is formed smoothly But may be heated while being rotated in a direction other than the above direction.

In the apparatus shown in Fig. 4, the bonded materials 1a and 1b are rotated such that the axes of the bonded materials 1a and 1b are located in the horizontal plane. Alternatively, for example, The shaft may be rotated so as to be positioned within the vertical plane.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited to these embodiments.

[Example 1]

Two pipes made of silicon nitride having an outer diameter of 28 mm, an inner diameter of 22 mm and a length of 1000 mm were prepared as materials to be bonded. These two pipes have the fitting structure shown in Fig. 2 (b). The inner sleeve shown in Fig. 3 was also used. The inner sleeve was made of silicon nitride, which is a pipe-like material. As the bonding material, a mixed powder having the composition and average particle diameter shown in Table 1 below was used. The mixed powder was mixed with ethanol to prepare a slurry, and a green sheet was prepared from the slurry by a conventional method. The green sheet was an annular shape having an outer diameter of 30 mm, an inner diameter of 20 mm, and a thickness of 80 占 퐉. Using these, ceramics bonded bodies were produced according to the apparatuses and processes shown in Figs. 4 (a) to 4 (d). The production conditions are as shown in Table 2 below. The obtained ceramics bonded body was subjected to the evaluations shown in Table 3 below.

[Examples 2 to 12]

A ceramics bonded body was obtained in the same manner as in Example 1 except that the conditions shown in Table 2 were used. The obtained ceramics bonded body was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Examples 13 and 14]

A silicon nitride block having a length of 30 mm, a width of 20 mm and a height of 20 mm was used as the material to be bonded. A 30 mm x 20 mm face in this block was faced to each other and heated under the state where the bonding material was interposed between the faces to obtain a ceramics bonded body. Details of the manufacturing conditions are as shown in Table 2. The obtained ceramics bonded body was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Comparative Examples 1 to 4]

A ceramics bonded body was obtained in the same manner as in the above example except that the conditions shown in Table 2 and Table 3 were used. The obtained ceramics bonded body was evaluated in the same manner as in Example 1. The results are shown in Table 3.

As is apparent from the results shown in the above table, it can be seen that the ceramics bonded body obtained in each example has a high bonding strength that is close to the strength of the material to be bonded. It can be seen that the ceramics bonded body obtained in each example can maintain the bonding strength even after it is exposed in a high temperature oxidizing atmosphere.

Claims (9)

A ceramic ceramics bonded body formed by bonding silicon nitride ceramics bonded materials to each other through a bonding site including silicon nitride particles and silicon oxynitride glass,
The ratio of the silicon nitride particles to the silicon oxynitride glass is 97: 3 to 60:40 in the cross-sectional view of the microstructure of the bonding site,
And the silicon nitride particles contained in the bonding portion are columnar. The method according to claim 1,
Wherein the aspect ratio (major axis / minor axis) of the columnar particles on the joint is 2 to 30. A method of manufacturing a ceramics bonded body in which silicon nitride ceramics bonded materials are bonded to each other through a bonding site including silicon nitride particles and silicon oxynitride glass,
A bonding material containing a mixed powder having a composition capable of forming a bonding site including silicon nitride and silicon oxynitride glass after heating is interposed between the materials to be bonded,
Wherein the bonding portion is heated while the bonding portion between the materials to be bonded is pressurized. The method of claim 3,
Wherein the mixed powder contains silicon nitride particles having an average particle diameter of 0.4 to 5.0 占 퐉. The method according to claim 3 or 4,
The bonding material is heated while rotating the bonding material around an axis orthogonal to the bonding surface of the materials to be bonded,
And rotating the member to be bonded such that the shaft is positioned within a horizontal plane. 6. The method according to any one of claims 3 to 5,
Wherein a green sheet formed using the mixed powder as the bonding material is used. 7. The method according to any one of claims 3 to 6,
Wherein the material to be bonded is tubular or rod-like, and the bonding material is heated while rotating the material to be bonded around the axis of the material to be bonded, with the bonding material interposed between the end faces of the material to be bonded. 8. The method of claim 7,
Wherein the end faces of the material to be bonded are in contact with each other when the end faces are brought into contact with each other, so that the positions of the central axes of the materials to be bonded are conformed. 8. The method of claim 7,
And an inner sleeve for positioning the shaft center of the material to be bonded is interposed on the joining portion.

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