JPS596939B2 - A strong layered body made of silicon carbide fibers and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silicon carbide fiber layered body and a method for manufacturing the same.

In particular, the present invention relates to a strong layered body made only of silicon carbide fibers without using a foreign adhesive, and a method for manufacturing the same.

Conventionally, in order to manufacture a layered body from fibers, the fibers are laminated and the contact points between the fibers are fixed by mutual friction or adhesive to form a predetermined shape, or it is made into a woven fabric. Layered bodies are manufactured from Nari fibers.

Examples of this include paper, carbon fiber layered material (carbon paper), and glass fiber woven fabric. However, in the layered body of fibers using adhesive in the layered body,
Properties are regulated by the adhesive that makes up the layered body. For example, in the case of a carbon layered body, carbon itself has excellent heat resistance, but since ordinary glue is used as the adhesive,
Carbon fibers can only be used at temperatures below, and the unique properties of carbon fibers cannot be exhibited at all.The shape of the laminate due to friction between the fibers is easily destroyed by external force and heat, and the layered structure made of woven fibers is Although the body retains its shape even when subjected to external forces and heat, it is not very useful when used in composite materials because the fibers do not complement each other in strength. Regarding silicon carbide fibers, as can be easily inferred from the method for manufacturing layered bodies such as carbon fibers, silicon carbide fiber layered bodies can be manufactured by using adhesives. However, the characteristics of silicon carbide fibers, such as heat resistance and electrical conductivity, are lost due to the use of adhesives, and their strength characteristics cannot be fully demonstrated even as woven fabrics. cannot be manufactured. An object of the present invention is to provide a strong layered body made of silicon carbide fibers and a method for producing the same without using a foreign adhesive. We focused on the fact that when threads made of molecular compounds are brought into contact with each other and preheated in a vacuum, the threads melt and join at the points of mutual contact, and after the preheating, the threads are fired at a high temperature in the range of 1000 to 2000°C. The present invention was completed by manufacturing a silicon carbide fiber laminate that does not use any adhesive.

The present inventors previously invented a silicon carbide fiber using an organosilicon polymer compound whose main skeleton components are silicon and carbon as a starting material, and a method for manufacturing the same, and published JP-A-51-1
No. 26300, JP-A-51-130324, JP-A-5
No. 1-130325, JP-A-51-149925, and JP-A-51-149926.

The present invention relates to an invention developed from the silicon carbide fiber of the above invention and a method for producing the same.

Next, the present invention will be explained in detail.

The reason why the threads made of the organosilicon polymer compound are melted and bonded to each other when the threads are preheated in vacuum while in contact with each other is as follows.

In other words, the thread made of an organosilicon polymer compound contains a considerable amount of easily volatile components, and the easily volatile components are composed of low molecular weight compounds, which melt at a relatively low temperature and dissolve the high molecular weight polymer. However, when the yarn is preheated in a vacuum, the easily volatile components are volatilized, causing the yarn to melt and melt. The volatilization state of easily volatile components in a vacuum is shown in Figure 1, where the volatilization of easily volatile components starts at about 100°C and starts at about 5°C.
The temperature increases rapidly from 00°C and almost ends at about 700°C. However, if the threads are in contact with each other,
This prevents volatile components from evaporating at the point of contact.
The threads melt and bond together at the point of contact. In the spun joining process, parts of the threads melt together and the components of each thread are completely and uniformly mixed at the point of contact. The strength, electrical resistance, heat resistance, and other physical properties at mutual contact points of the fibrous layered body do not change compared to other parts, and there is no change in chemical components.

The state of the silicon carbide fiber layer is different from that of woven fabrics produced by normal methods, and because the silicon carbide fibers are joined at the contact points, the strength characteristics of the layered body are extremely good.The reason for this is as follows. This will be explained using a simple schematic diagram.

That is, FIG. 2 shows a schematic diagram of a normal woven fabric consisting of six fibers that are not joined together. In the same figure, fiber 2
When a tensile stress is applied to the fiber 2, the tensile stress acts only on the fiber 2, as shown by the arrow in FIG. On the other hand, the fourth
In the schematic diagram of the silicon carbide fiber layered body shown in the figure, when tensile stress is applied to the fibers 12, as shown by the arrows in FIG. part of it is dispersed into fibers 11, 13, 14, 15, 16 through the
Fiber 12 can withstand greater stress than fiber 2. The silicon carbide fiber layered body of the present invention is mainly used for producing composite materials with plastics, rubber, metals, ceramics, and others.

In conventional fiber-reinforced composite materials, the strength varies depending on factors that occur during the manufacturing process or due to differences in the physical or chemical properties of the fibers and the matrix. One of the major factors is the wettability between the fiber and matrix. In a fiber-reinforced composite material with poor wettability, the fibers and matrix cannot complement each other to exhibit high strength as a composite material.
However, in a composite material using the silicon carbide fiber layer state, the composite material exhibits high strength properties even if the wettability between the fibers and the matrix is poor. This reason is the 6th. This will be explained using a schematic diagram of the composite material. In the figure, the shaded area shows the matrix, the solid line shows the fiber, and the black circle shows the joining part of the fiber. When a tensile stress is applied to the composite material, the fibers are pulled, and therefore stress is applied to the matrix portion to cause the layered body to deform from a square to a diamond shape due to distortion. Since the matrix retains a high resistance to deformation stress, the strength of the composite material can be very high due to the high tensile strength of the fibers that resist this deformation. The effect of the resistance force against the external force is also considered to be due to the fact that in the composite material, the fibers and the matrix are strongly bonded at the joints between the fibers. The silicon carbide fiber layer is therefore advantageously used for composite materials that require strength even under conditions where the strength of the matrix itself is significantly reduced, for example at high temperatures. The silicon carbide fibers used in the present invention are produced using organosilicon compounds classified into the following types (1) to Q1 as starting materials.

(1) Compounds containing only Si-C bonds.

(2) Compounds containing Si-H bonds in addition to Si-C bonds.

(3) A compound having a Si-Hal bond.

(4) Compounds having Si-N bonds.

(5) A compound having a Si-0R (R-alkyl, aryl) bond.

(6) A compound having a Si-0H bond.

(7) Compounds containing Si-0H bonds.

(8) Compound containing S1-0-Si bond.

(9) Organosilicon compound esters. QO organosilicon compound peroxide.

From at least one or more organosilicon compounds belonging to the type (C~QO), silicon and carbon are mainly converted by a polycondensation reaction using at least one of irradiation, heating, and addition of a polycondensation catalyst. An organosilicon polymer compound is produced as a skeleton component.

A spinning stock solution is prepared from the organosilicon polymer compound, and this is spun to form a yarn made of the organosilicon polymer compound.

Next, several examples of methods for laminating the yarns will be described.

After the spun yarn is wound around a cylinder of a predetermined size at a predetermined interval as shown in FIG. 7, the yarn is cut as shown in FIG. Arrange in containers. The threads are laid on top of the arranged threads in the same manner. In the lamination, the orientation angle of the lower thread layer and the upper thread layer can be set arbitrarily as necessary, and the number of threads to be laminated can also be set as desired as necessary. In addition, in order to manufacture silicon carbide fiber layered bodies with cylindrical, prismatic, and other shapes, threads made of an organosilicon polymer compound are first wound in a single layer around a predetermined mold, and the threads are set at a predetermined angle to each other. Wrap them together so that
By repeating this process a predetermined number of times, a layered body of threads having a predetermined shape can be obtained.

In order to further laminate the threads, the number of threads is 0.1 to 1000.
Cut into lengths in the range of 0 mm, preferably 1 to 1000 mm, disperse the short yarn in water, and stack and dry the short yarn in the same manner as ordinary paper. It is possible to make a layered body of short threads.

The laminated yarn was placed in a vacuum heating furnace and heated in vacuum for 40 minutes.
The mutual contact points of the threads are preheated in a temperature range of 0 to 800°C to melt and bond them, and then heated in a vacuum or with an inert gas, C
A silicon carbide fiber layered body can be obtained by firing at a high temperature in a temperature range of 1000 to 2000° C. in an atmosphere of one or more selected from O gas and hydrogen gas.

In the method of the present invention, if the preheating temperature is lower than 400°C, fusion bonding will not be sufficiently performed, whereas if the preheating temperature is higher than 800°C, fusion bonding will be sufficiently performed, but if the preheating temperature is higher than 800°C, heating in a vacuum will not necessarily be performed. Because you don't need
It is necessary to preheat in vacuum in the temperature range of 400-800°C. For high temperature firing, 1000℃
When the temperature is lower, less SiC is produced and the strength of the layered body is weaker.

On the other hand, if the temperature is higher than 2000° C., the decomposition of the generated SiC will be significant and the fiber shape will be damaged. When preheating the spun layered body in a vacuum, placing a breathable weight on the layered body and applying slight pressure can improve the bonding of the yarns, and also press the yarns to form a tape. It is also possible to form a layered body.

Note that the silicon carbide fiber layered body of the present invention also contains free carbon like silicon carbide fibers, but
The free carbon can be removed by firing at a temperature range of 600 to 1500° C. in an oxidizing atmosphere, if necessary.

Next, the present invention will be explained with reference to examples. Example 1 Organosilicon polymer compound thread with a diameter of 15 μm was
Trap with V7l 52 (1771 cylinder with 1m spacing between threads)
The threads were arranged on the plate by rolling the cylinder over a 60×60 (V7l) quartz glass plate while removing the threads.

On top of the arranged yarns, yarns were laminated using a cylinder using the same method so that the angle between the upper and lower yarns was about 90°.
A quartz glass net is placed on top of this thread layer to prevent the threads from scattering, and the quartz glass plate is placed in a vacuum heating furnace and preheated by slowly increasing the temperature from room temperature to 800°C over 6 hours while creating a vacuum. The threads were then joined. Furthermore, in order to perform high-temperature firing, the preheated thread was placed from a quartz glass plate onto a SiC brick, and heated to 1300 m from room temperature under an argon atmosphere.
The mixture was heated to ℃ for 2 hours and fired at a high temperature to obtain a silicon carbide fiber laminate. Fifty sheets of this laminate were stacked and the aluminum was melted to produce an aluminum composite material of 2 x 10 x 50 CWL. This silicon carbide fiber-reinforced aluminum composite material contains 40% by volume of fibers and has an extremely high tensile strength of 120k9/M4, making the layered material extremely useful as a reinforcing material for the composite material. Example 2 Using the same cylinder as in Example 1, an organosilicon polymer compound thread with a diameter of 20 μm was wound around the cylinder with an interval of 1 mm, and cut linearly in the length direction of the cylinder with a knife. The cylinder was rolled on a 60×60 (V7l) quartz glass plate while removing the threads to arrange the threads on the plate.

The arrayed yarns were laminated four times in total using the same method so that the yarns formed an angle as shown in FIG. 8. A quartz glass net was placed on top of this thread layered body, and the quartz glass plate was placed in a vacuum heating furnace, heated to 800 m from room temperature while being evacuated.
℃ for 4 hours, preheated to bond the threads, and then transferred the preheated threads from a quartz glass plate to Si.
It was moved onto a C brick, heated from room temperature to 1400° C. over 2.5 hours in an argon gas atmosphere, and fired at a high temperature to obtain a silicon carbide fiber layer. When this layered material was attached to the inlet of an electric furnace using a siliconite heating element and tested for its heat-suppressing effect, the temperature, which normally falls from 90°C, dropped to 35°C, and it was not possible to see inside the electric furnace through the layered material. As a result, the efficiency of work using an electric furnace has been doubled. Example 3 Organosilicon polymer compound thread with a diameter of 15 μm and a length of 2 to 1
The threads were cut into non-uniform lengths within a range of 100 mm, dispersed in water, and then stacked using a 30 x 50 quartz glass container in the same manner as Japanese paper.

A quartz glass net was placed on top of this short yarn laminate and thoroughly dried. This laminated short yarn was placed in a vacuum heating furnace with the container and screen still attached, and heated from room temperature to 800 m while creating a vacuum.
℃ for 8 hours to preheat and join the threads.
Furthermore, the preheated thread was transferred from the quartz glass container to SiC.
Move onto a brick and heat to 150℃ from room temperature in an argon atmosphere.
The temperature was raised to 0° C. over 5 hours and fired at a high temperature to obtain a silicon carbide fiber layered body. In this layered body, silicon carbide fibers accounted for approximately 21% of the surface area. A composite material made by coating this layered body with stainless steel using a plasma spray method had a strength that could withstand use up to 1000°C as a result of a high-temperature tensile test. Example 4 Organosilicon polymer compound thread with a diameter of 20 μm and a length of 7 cm
The short spun fibers were cut into pieces, dispersed in water, and stacked in a 30 x 50 quartz glass container using the same method as Japanese paper.

A quartz glass net was placed over the short yarn laminate to prevent the yarns from scattering, and the short yarn laminate was thoroughly dried. This short yarn laminate, together with the container and screen, was placed in a vacuum heating furnace, and the temperature was raised from room temperature to 800°C over 8 hours under vacuum to preheat and bond the yarns.Furthermore, the preheated yarn was placed in a quartz glass container. The material was then transferred onto a SiC brick, heated from room temperature to 1400° C. over 5 hours in an argon atmosphere, and fired at a high temperature to obtain a silicon carbide fiber layered body. In this layered body, silicon carbide fibers accounted for approximately 41% of the surface area. When this layered material was used as a sample holder for chemical polishing using hydrofluoric acid, it had excellent strength and oxidation resistance, and could be used for a long time. Example 5 Diameter 20 μm
A thread made of an organosilicon polymer compound with a diameter of 5 (V7l)
■ I
The yarn was wound at intervals of 10 times, with the angle between the upper and lower yarns being approximately 90°.

Place this as a mold in a vacuum heating furnace and heat it to 1000℃ from room temperature.
After preheating by slowly increasing the temperature over 8 hours, the assembled cylinder was removed and heated further in vacuum from room temperature to 150
The temperature was raised to 0° C. over 4 hours and fired at a high temperature to obtain a silicon carbide fiber layer. The tensile strength of this layered body is 410k
9/MA tensile strength of silicon carbide fiber 340k
It was about 1.3 times that of 9/Md. The thermal shock resistance of the layered body coated with alumina by plasma spraying was approximately twice that of ordinary alumina.

Example 6 Silicon carbide fibers were prepared in the same manner as in Example 4. 'A layered body was produced.

This layered body contained fibers with a surface area of about 80%, and the surface of the layered body was coated with magnesia by a plasma spray method. The density of this magnesia-coated layered body is 1
．． 61, which is extremely small and has excellent heat resistance,
It was found that it can be used as a heat-insulating diaphragm for high temperatures of 11,400°C or higher. As described above, the silicon carbide fiber layered body of the present invention has heat resistance, oxidation resistance, and abrasion resistance equivalent to that of silicon carbide fibers, and its strength properties are better than those of silicon carbide fibers because the applied stress is two-dimensionally distributed. Because of its excellent properties, this laminate can be used in its original form for surface heating elements, luminous bodies, fire prevention materials, heat-resistant curtains, acid-resistant diaphragms, chemical industry materials, ceramic materials, nuclear reactor materials, and nuclear materials. It is used for fusion reactor materials, aircraft materials, rocket materials, ocean development materials, construction materials, and others, and is also used as composite materials with rubber, plastics, metals, ceramics, cellulose, and others. It can be used for various purposes, examples of which are described below.

(a) Composite materials with rubber: tires, rubber containers, etc. (b) Composite materials with synthetic resins (1) Hand lay-up method: tanks, pools, ducts, housings, etc. Molding parts of trucks and buses, (
2) Spray-up method: Molding of ports, tank linings, bathtubs, tanks, housings, etc. (3) S
MC molding method: Forming tanks and boxes, (4) Premix molding method: Forming tubes, boxes, plates, and tanks (transfer molding and compression molding are possible) (5) Filament Winding method: Vibrator, tank body, reinforcement of vibrator, molding of ducts, (6) Continuous panel method...
・・・Formation of flat plates, corrugated plates, nicham sandwich plates, etc., (7) Pultrusion method (pultrusion molding method) ・・・・
・・・・Forming pipes, rods, channels, square vibes, I-beams, etc., FRP pipes for bridges, frames, supports, support frames,
Sashes, sandwich boards, (8) Cold breath molding method: Forming of tanks, cooling towers, ports, construction containers, automobile exterior parts, machine tool covers, etc., 1) Molding of metals, cellulose, ceramics, and others Composite materials (c) Building materials: panels, domes, trailers, walls, ceiling materials, flooring materials, cooling towers, septic tanks, sewage tanks, water supply tanks, hot water piping, drainage pipes, etc. (2 ) Aircraft, space development equipment materials...
...fuselage, wings, helicopter drive shaft,
Jet engine compressors, rotors, stators, blades, compressor casings, housings,
Nose cones, rocket nozzles, brake materials, tire cords, etc. (3) Marine materials...boards, yachts, fishing boats, work boats, etc. (4) Land transportation equipment materials...
・・Vehicle front head, side panels, roofs, water tanks, toilet units, seats, car bodies, containers, road signs, guardrails, pallets, tank truck tanks, bicycles, motorcycles, etc. (5) Corrosion-resistant equipment materials・・...tanks, tower ducts, staff, vibrators, etc., (6) electrical materials... surface heating elements, varistors, igniters, thermocouples, etc., (7) sporting goods... ...Ports, bows, skis, snowmobiles, water skis, glider bodies, tennis rackets, golf shafts, helmets, putts, racing jackets, etc. (8) Machinery materials...
...Gaskets, packing, gears, brake materials, friction materials, abrasive materials, blades, etc. (9) Medical equipment materials
... Dentures, prosthetic limbs, etc., a... Audio equipment materials...
... Cantilevers, tone arms, speaker cones, voice coils, etc. (11) Heat-resistant materials ... Heat-resistant plates, heat-resistant tubes, heat-resistant plates, high-temperature containers, etc. (1
zOthers: Chemical industry materials, ceramic materials, nuclear reactor materials, nuclear fusion reactor materials, ocean development materials, etc.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the heating temperature and residual weight of threads made of organosilicon polymer compounds in vacuum, Figure 2 is a schematic diagram of woven fabric, and Figure 3 is a diagram of the fibers in the schematic diagram of Figure 2. Fig. 4 is a schematic diagram of a silicon carbide fiber layered body, and Fig. 5 is a schematic diagram of the stress effect when tensile stress is applied to fiber 12 in the schematic diagram of Fig. 4. Figure 6 is a schematic diagram of a composite material using a silicon carbide fiber layered body, and Figure T is an explanatory diagram showing an example of a method for manufacturing a silicon carbide fiber layered body using a cylinder. , FIG. 8 is a diagram showing one example of how silicon carbide fibers are arranged.

Claims (1)

[Scope of Claims] 1 Thread-like bodies made by spinning organosilicon polymer compounds whose main skeleton components are silicon and carbon are laminated, and then preheated in vacuum to bond the filament-like bodies constituting the layered body to each other. A strong layered body made of silicon carbide fibers whose contact portions are fused and bonded and then fired at a high temperature to combine the main silicon and carbon in the skeleton components of the organosilicon polymer compound to form SiC. 2 Thread-like bodies made by spinning organosilicon polymer compounds whose main skeleton components are silicon and carbon are laminated in layers, and then the temperature is gradually raised in a vacuum to preheat within a temperature range of 400 to 800°C. The contact portions of the spun yarns constituting the layered body are melted and bonded, and then fired at a high temperature within a temperature range of 1000 to 2000°C to combine the main silicon and carbon in the skeleton components of the organosilicon polymer compound. A method for producing a strong layered body made of silicon carbide fibers, characterized in that the fibers are made of SiC.