JPS60205071A - Ceramic bellows - Google Patents

Abstract

PURPOSE:To make a ceramic thin sheet applicable under the high temperature environment of more than a temperature of 900 deg.C, by joining plural ceramic thin sheets consisting of silicon nitride, silicon carbide, etc., with a ceramic bonding material composed of te same type component as this thin sheet. CONSTITUTION:A doughnut plate type ceramic thin sheet 1 provided with a round hole in the almost nearly central part is superposingly set up in bellows form via a spacer 2 so as to cause end edge parts themselves at both inner and outer circumferential sides of two ceramic thin sheet surfaces adjoined with each other to be alternately joined in succession. A contact surface between the ceramic thin sheet 1 and the spacer 2 is joined together with a ceramic bonding material 3. As for the ceramic thin sheet 1, for example, those of silicon carbide, silicon nitride, cyaron, etc., are suitable. The ceramic bonding material 3 consists in the same or similar component as the main component of the ceramic thin sheet 1.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a bellows attached to a fluid passage for stress absorption, etc., and is particularly designed to be suitable for use in a high-temperature environment of about 900°C or higher. related to ceramic bellows.

(Prior Art) In general, in fluid passages, bellows and the like have conventionally been used as cushioning materials to absorb displacements caused by vibrations and thermal deformation occurring therein and to prevent damage to the flow passage system. Conventional bellows of this type have generally been made of metal such as stainless steel, taking into account the elasticity and workability that the bellows should have.

By the way, in recent years, as gasoline engines and diesel engines have become smaller and have higher output, the combustion temperature inside the cylinder has increased further (particularly when excess air is supplied, the combustion temperature becomes even higher), and the exhaust gas temperature has increased. A new engine that can exceed 900 degrees Celsius is being developed. When bellows are used in the exhaust system of this engine, the bellows made of iron-based castings that have been used conventionally suffer from oxidation deformation, cracks, and lack of heat resistance.

In addition, in recent years, the development of ceramic housings and turbine wheels for turbochargers has progressed, and in this case, if engine vibrations are directly transmitted to ceramic housings or turbine wheels through the intake and exhaust pipe system, they will be damaged. There is rI & power to do. However, in engine applications, conventionally used bellows cannot sufficiently absorb engine vibrations and displacements. Therefore, even in high-temperature environments of approximately 900℃ or higher,
A bellows that satisfactorily performs its functions was desired.

(Object of the Invention) The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to be applicable to high-temperature environments of approximately 900°C or higher (for example, in high-temperature gas flow paths). Our objective is to provide ceramic bellows.

(Structure of the Invention) The ceramic bellows of the present invention includes a plurality of ceramic thin plates made of silicon nitride, silicon carbide, etc., each having a hole in the center. If necessary, the edges of the outer side 91 are alternately connected with each other through ceramic spacers, and the contact area between each member is defined as the main component of the ceramic thin plate in the previous issue. The fc is characterized in that it is bonded with a ceramic bonding material having similar components.That is, the present invention is characterized in that the bellows k1 is made of a ceramic bonding material that maintains sufficient elasticity in a high temperature environment.
It is a superimposed product. Furthermore, to describe the present invention in detail with reference to the drawings, the bellows of the present invention is as follows:
As shown in the figure and FIG. 2, t6? Make a round hole in the Y medium heat and insert the plate l... into the donut plate-shaped ceramic 71 between the inner circumferential edge and outer circumferential edge of the plate surfaces of both adjacent ceramics li') A bellows is made by arranging the ceramic thin plates 1 and the spacers 2 so that they are alternately connected with each other through ceramic spacers 2 in a so-called bellows shape, and bonding the contact surfaces of the ceramic thin plates 1 and the spacers 2 with ceramic bonding materials 3, 3. be able to. Ceramics 7', j
i board trL approx. c+o.

Any material may be used as long as it is made of a ceramic material that has sufficiently high elasticity in a high-temperature environment of .degree. In addition, the thin 4h1 shape has a hole in the center of the ILS when used as a fluid flow path.
The shape of the thin plate 1' is not limited to the circular shape shown in FIG. 1, but may be an elliptical thin plate 1' as shown in FIG. Furthermore, thin 182
The dimensions of 1 (for example, inward outer diameter, thickness, etc.) may be set as appropriate by taking into consideration the stress applied to the bellows fC and the amount of deformation allowed for the bellows. , If the thickness of the ceramic thin plate (I-jrP- is too large, the amount of deformation will be extremely small, but if it is made too thin, there will be a shortage of ';!l1In'', so the thickness of the thin plate l/7) is , about (), 1~1., Ovn
It is convenient to have a culm noise of about 0.2 to 0.7 when the culm is approximately x.

- The ceramic bonding material 3 used in the invention must have the same or similar component composition as the main component of the ceramic thin plate 1, preferably when its helical component is the same component as the ceramic s@t, and further Preferably, the ceramic component is the same as Ceramic 9:Plate 1 and has the same composition. For example, when a ceramic thin plate has a composition of 94 percent by weight of silicon oxide (Si, N4), 1 to percent by weight of yttrium oxide (Yz 03 ), and 3 percent by weight of spinel (MgA404), If it is a ceramic material whose main component is silicone f! In addition, the ceramic bonding material must contain hollow silicon or a similar component. , the ceramic thin plate is silicon carbide (SiC) 97.
6 IIT Lifting Padding - When the ceramic material is composed of silicon carbide as the main component, as in the case where the composition consists of centaurbon black double weight percent and boron carbide 0.4 percent by weight, the ceramic bonding material A bond H that requires inclusion in silicon carbide or a similar component and further includes silicon carbide, carbon black, boron carbide, aluminum, etc. may be used. Conventionally, methods of joining ceramics together include methods using glass as a joining material and methods of joining with a metal M interposed between them.11. -C is here. However, if glass or the entire area is used as a bonding material for ceramics such as silicon nitride or silicon carbide using these methods, if vibrations or stress are applied under a high-radiance environment of about 900°C, the problem will occur. Bonded ceramics 1 prevent cracks and cracks in the bonded parts, making them easier to separate.

On the other hand, if a bonding material having the same and similar components as the main components of the ceramic thin plate is used according to the present invention, the bellows VC will not be damaged even if large vibrations and stress are applied at high temperatures of approximately 900°C or higher. No cracks or cracks occur in the joints between thin ceramic plates, and the joint strength does not deteriorate. This is because the bonding material of the present invention has a composition similar to that of a ceramic thin plate, and has heat resistance that is almost the same as that of the thin ceramic plate.
It is also assumed that this is due to the fact that since the components are similar, the compatibility with the ceramic thin plate during firing is good and the bonding strength is increased. In addition, the bonding material of the present invention is VC-processed so that it can be easily coated on the surface of a ceramic (W) plate! ζ
For example, it is preferable to use a slurry-like or paste-like bonding method in which a ceramic powder containing the same main components as the main component of the ceramic thin plate is mixed with a suitable medium (such as butyl alcohol) and agitated. good.

Further, the ceramic spacer 2 used in the present invention has a diameter of about 9
It is fine if it does not decompose or break even if used at high temperatures of 0°C or higher, does not cause cracks on the interlocking surfaces, and is preferably one that is the same as the main component of ceramic thin plates or ceramic bonding materials, or Chilled with ceramic material containing ingredients similar to Tsukasa.

In addition, when stacking ceramic thin plates, a second
As shown in the figure, a ceramic spacer 2 may be interposed, but as shown in FIG.
The inner periphery glIl and both the outer and inner edges 1/C thick parts 4, 4 are provided oppositely to each other, or as shown in FIG.
It is also possible to eliminate the need for spacers altogether by alternately providing thick wall portions 4' on one side or the other so that the ceramic thin plates are arranged in parallel with a desired spacing. Another possible method is to bend and curve ceramic thin plates to create a certain spacing. The side edges are slightly bent in opposite directions f
A bellows formed by stacking c-shaped ceramic thin plates 1c alternately on the front and back sides, and a bellows formed by stacking ceramic thin plates 1d with a corrugated egg-shaped cross section alternately on the front and back as shown in Fig. 7. etc. can be mentioned. This type of bellows not only does not require a spacer, but also can expand and contract significantly and has a relatively large amount of deformation tolerance.

Further rCl Fig. 8V As shown in Fig. 8, bend the inner peripheral edge and the outer 1iffi 1+II end M part in the opposite direction, and also bend the intermediate part between the inner peripheral edge and the outer peripheral edge on the inner peripheral side and The bellows is made by stacking ceramic thin sheets [1e... ! However, if the allowable amount of deformation is large and the stress applied to the joint surface between thin ceramic plates is small, for example, the doctor blade method
A method of punching out a ceramic thin plate' (R-) into a predetermined shape, by spraying a slurry-like ceramic #!l product onto a certain board to form a predetermined shape. 〆l) Form a ceramic sheet and punch it into a predetermined shape by cutting it;
, by firing a ceramic thin plate obtained by a method such as a method of producing 1iFi on an i-plate, an extrusion method in which punching into a predetermined shape after extrusion molding, or a powder press method or an injection molding method. l! ! When joining ceramic thin plates that are crushed together, for example, a slurry-like or paste-like ceramic bonding material is applied to the ceramic 111 plate before phosphoric acid, and the ceramic thin plates are overlapped with a necessary spacer. , and then firing, and joining the ceramic thin plates to each other at the same time as the thin plates themselves are fired. Alternatively, the firing may be performed in advance. j (This may be carried out by applying a ceramic bonding material such as a slurry to thin ceramic plates, overlapping the thin ceramic plates, and then firing them to bond the thin ceramic plates to each other.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

Example 1 Ceramic powder (average particle size: 077 microfron) having the composition of evaporated silicon (813N4) 94% by weight, yttrium oxide <YtO 13% by weight, and spinel (MIL'ALy 04) triple grade bart. A slurry containing 50 volume percent of ceramic powder was prepared by mixing methyl cellulose, polyvinyl alcohol, and water, and this was extruded through a slit (0.65 ml inside) of an extruder to form a ceramic sheet. , the nuclear sheet is shaped like a donut (
The inner diameter is 50 mm, the outer diameter L is 25 vm), and then, as shown in FIG.
6 was placed on the lower end side and subjected to natural softening to produce a precursor molded body 7 of a ceramic thin plate. The molded body 7
ft As shown in Fig. 1O, foamed rn+:P(BN) powder was placed on the inclined surface and end side of a firing table 8 made of silicon nitride ceramics, and the pressure was reduced while heating to about 500°C. The organic binder of methylcellulose K (T) was removed from the molded body 7, and then heated at 1780°C in a nitrogen atmosphere.
The ceramic thin plate 1C shown in FIG.
' was manufactured. The dimensions of 'Ag plate 1c' are 17 x 0.5
-1 The inner diameter was 40mm and the outer diameter was 100mm.

On the other hand, all W4 ceramic bonding materials have a composition of 85 weight percent silicon nitride, 5 weight percent yttrium oxide, and 10 weight percent spinel! I! !
Shita. After that, one hiramix thin plate 1c' of the La II period
20 sheets were stacked on top and back alternately, and the contact surfaces of the inner and outer edges were coated to a thickness of about 10 microns using the pre-prepared ceramic bonding printing method, and then, Superimposed thin plates' (I - approx. 170 mm in nitrogen atmosphere)
The material was heated to 0.degree. C. and then maintained for 2 hours for firing to produce a bellows as shown in FIG. Incidentally, during firing, in order to prevent deformation, coarse granules of silicon nitride were filled into the mass of stacked ceramic thin plates 1c'.

When we conducted a performance test on the manufactured bellows, it was found that 900
At a high temperature of ℃, adjust the amount of displacement to within 1.0 degrees.
Even when the bellows was expanded and contracted more than once, no abnormalities such as cracks were observed on the bellows surface.Also, this bellows was destroyed by giving an axial displacement.The amount of fracture displacement of this bellows was 3.5 times. Example 2: 97.6% by weight of silicon carbide with an average particle size of 0.45 microns, 2% by weight of carbon black with an average particle size of 210A, and an average particle size of Ceramic powder 'V/J mixed with -r setone as a solvent so as to have an i11 composition of 0.4i1j 0.4i1j product percent of 0.063 micron 11 carbide is applied to 100 parts of 1.1 N force end. 17i1jj 4 parts polyvinyl butyral, 8 ply 1
A C1 slurry was prepared by mixing 60 parts by weight of phthalate ester and 60 parts by weight of ethyl alcohol.
(It was formed into a laminox sheet. In this case, the organic i'1g agent such as ethyl alcohol was evaporated and filtered. Next, the sheet was placed on a hot plate 9 shown in FIG. 12. There is a person inside, apply moxibustion vigorously to a certain degree of heat and pressure, and press ytr J: (Figure VC7).
: The inner cylinder side and both edges of the outer and inner sides have scratches and scratches on both sides.

Ceramics 1fVtfj l a provided on the opposite side
'f Manufactured.

On the other hand, silicon carbide Ji97.6 with average particle size o and ss miku σ
Weight percent, carbon black with average particle size 210A 1.6 weight percent, [ξ average particle diameter 0.63
Ceramic powder having a composition of 0.4 weight percent of micron boron carbide and 0.4 weight percent of powdered aluminum with an average particle size of 1 micron is mixed with a suitable amount of butyl alcohol to form a slurry of ceramic bonding. The material was prepared.

Using a trowel, stack 20 of the thin ceramic plates La' Th on top and bottom alternately, and apply the prepared ceramic bonding material to about 15 mm using a printing method.
The thin plates were coated to a thickness of microns, then stacked and placed in a graphite container, and heated to about 210 μm in an argon gas atmosphere.
Heat the iron to 0℃ and keep it there for 1 hour.1. I did the firing.

In order to maintain this superimposed shape, a graphite plate was inserted between each thin plate.

Thus, a bellows as shown in Fig. 14 was manufactured L fc
o The dimensions of this bellows are an inner diameter of 40mm, an outer diameter of 110m, a thickness of the joint part of 1.50mm, and an average thickness of the other flexible parts of 0.55vsm.

Also, the effective inner diameter was 50 circles and the effective outer diameter was 100 circles. When we conducted an expansion/contraction performance test on this bellows, we found that 11
At a high temperature of 00℃, adjust the room height to 1.0m and
Even when the bellows was compressed more than 06 times, no cracks occurred on the bellows surface (1:11), and there was no breakage of the bellows at all. 1k, the extensional fracture displacement ζ) of this bellows at room temperature was 3.7 m (the fracture point is about half of the joint part and 1IT4.Q part and fc)
.

(Effects of the Invention) As explained above, the ceramic bellows of the present invention is produced by laminating ceramic thin plates made of arsenic foam and forming an approximate structure with Approximately 90
() It is possible to obtain a sufficiently large temperature even under high temperature conditions of 1!?Ii at temperatures above ℃;
It is necessary to remove the metal flow path in the exhaust gas system of an automatic engine, etc., which forms a golden shadow.

[Brief explanation of drawings]

ff11 is a plan view showing a typical example of the Naramix bellows of the present invention, and FIG. 2 is a plane II-II*! of FIG. 1. break in ＋＋'
+i II4, Fig. 3 is a plan view showing a modified example of the ceramic thin plate of the bellows in Fig. 1, Fig. 4 (not shown) (7 Fig. 8 is a view showing various other typical examples of the bellows of the present invention, Fig. 9 [ Figures 1 to 7 are diagrams showing the entire process of manufacturing a bellows according to one embodiment of the present invention, and Figures 12 to 14 are diagrams showing the manufacturing process of a bellows according to another embodiment of the present invention. In the figure, 1.1', la, la', lb, lc, Ic', ld. le-... Ceramic thin plate 2...
...Sube 3... Ceramic bonding material Fig. 1 Fig. Fig. 3 Fig. 1' Fig. 4 Fig. 5 O/Fig. 6 C Off Fig. 28 Fig. 29 Fig. Fig. 12 Fig. 13 18' year old 14 figure

Claims (1)

[Claims] A plurality of ceramic thin plates made of silicon nitride, silicon carbide, etc. and having a hole in the center are connected so that the inner edge and the outer edge of the adjacent ceramic thin plates are alternately connected to each other. If necessary, the ceramics are arranged one on top of the other with a ceramic spacer interposed therebetween, and the contact portions between the members are bonded with a ceramic bonding material having the same or similar components as the main components of the ceramic thin plate. Made of bellows.