JPS6191063A - Powdery refractory material containing silicon carbide shortfiber and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a powdered refractory material uniformly containing short silicon carbide fibers and a method for producing the same.

As is well known in the prior art, silicon carbide fibers have excellent heat resistance, low coefficient of thermal expansion, and excellent thermal shock resistance. In addition, it has a low specific gravity and a high strength-elastic modulus. For these reasons, silicon carbide fibers are used as materials for fiber-reinforced composite materials such as various heat-resistant materials.

Problems with conventional technology How to obtain carbonized silica fibers 1 For example, 4? Kaisho 52-
Although it is described in Japanese Patent No. 70122, the process of synthetically spinning an organosilicon polymer such as polycarbosilane and firing it is complicated, so the cost is very high. Also, 81
It has also been proposed to obtain silicon carbide whiskers from a mixed gas such as C2, etc. and methane, but it is difficult to mass produce.

The cost is very high as well. Also, this whisker is 1
It is short, about 0 to 15 μrn, and is insufficient as a composite fiber. Furthermore, regarding compounding.

It is difficult to mix whiskers and powder uniformly or in large quantities.

OBJECT OF THE INVENTION The purpose of the present invention is to solve the disadvantages of conventional methods in terms of cost and in the mixing process, and to provide fiber reinforced fibers made of silicon carbide short fibers that can be mass-produced at low cost and have excellent uniform mixing properties. An object of the present invention is to provide a material for composite material and a method for manufacturing the same.

SUMMARY OF THE INVENTION 1 According to the present invention, silicon (Sl) component (metal 8i
etc.) and fibrous carbon (C component (carbon fiber, etc.) are bonded with an organic binder and brought into contact, and fired in a non-oxidizing atmosphere to react with the carbon fibers in the silicon carbide or silicon nitride powder matrix. Provided are a composite material in which short silicon carbide fibers produced by the process are uniformly dispersed, and a method for manufacturing the same.

Preferred Embodiment The silicon component used in the present invention includes metal silicon, silica powder, colloidal silica, 810°81, N4, and the like. In addition, organic silicon compounds such as sto4
．． Polycarbosilane and ethyl silicate can also be used.

These silicon components can also be used alone.

Alternatively, they may be used in combination.

As the fibrous carbon component, organic fibers such as polyvinyl alcohol, polyacrylonitrile, rayon, polyester, and other commercial products can be used. In particular, as carbon fibers, carbon fibers themselves, graphite fibers, flame-resistant fibers, kynor fibers, and commercially available products thereof are used.

As an organic binder used to closely bind silicon components and fibrous carbon components.

Organic polymers such as PVA, polyethylene oxide, CMC, Metrose, etc. can be used. These binders are particularly effective when metallic silicon or silica powder is used as the silicon component. As will be described later, the organic binder becomes charcoal IA#ζ during the firing process. , ``First, the silicon component, carbon component, and organic binder are mixed. In this case, the amount of silicon component and carbon component is 1
The following reaction formula St+O→Another 0゜8401+50→SmuO+
200 etc., it is determined by the weight ratio of 85 and 0 based on chemical theory.

As for the amount of organic binder, it is sufficient that the solid content binds component 81 and component C in close contact with each other.

For example, 1 to 20 parts by weight is suitable for 100 parts by weight of the 85 components and the 0th order component. The organic binder may be dissolved in a solvent in advance. The solvent used in this case may be water or any other organic solvent such as benzene, toluene, acetone, hexane, methyl alcohol, and ethyl alcohol. The organic binder may also be used in solid form.

The components mixed in this way are formed into particles of an appropriate size in advance to make it easier to crush the 1 reactant.
The particle size is preferably 5 to 20 mm.

This granulation step may be carried out by any suitable known means.

Next, the silicon component and the carbon component are combined with an organic binder and dried by an appropriate method in order to bring them into close contact with each other.

The drying temperature and time vary depending on the organic binder used, but are approximately 1 hour at 50 to 100°C.

The dry product thus obtained was washed with N1 argon, NH,
Calcination is performed in a non-oxidizing atmosphere such as gas at a temperature range of 500° to 2100°C.

In this firing process, the following reactions occur at each temperature stage.

(1) Approximately 100 to 800''C: Organic fibers are carbonized.

(II) About 800 to 1400@O: The following reaction occurs on the surface of the male carbon.

S Todoroki +O-+8i0 (book 1400-2100'O: f9i +O-
+SiO(7) reaction occurs to the inside of the fibrous carbon.

On the other hand, in the matrix, 840, 8
1. Powder number N is produced.

581 + 2N, →81. N4 (about 1400'0)8
i +0 →B10 (1400'○ or more) 810,
+50-+810+200 (2000'○)5810
, +2N, +60 → S Todoroki, N4+600 (150G@
In the firing step, the granular reaction product solidified by heating is then pulverized, which can be easily carried out using a mortar or the like. As previously mentioned.

The reaction product is obtained in a state in which short silicon carbide fibers are uniformly dispersed in a matrix of Sl0, 81, N, and powder. The powder forming the matrix is composed of sio, Sl, N4, or a mixture thereof depending on the St acid component raw material and firing conditions.

The reaction product obtained by pulverization is dispersed in water, and the powder particles of the short silicon carbide fibers and the matrix can be easily separated using a filter.

As described above, in the present invention, ζζ silicon carbide fibers are uniformly dispersed in the 8i0 and Betsuhata N powder matrix.

It provides raw materials for fiber-reinforced composite materials.

Furthermore, the short silicon carbide fibers separated from this are promising as reinforcing fibers.

Examples of this invention are shown below.

Example (1) and 100 parts by weight of metallic silicon powder (average particle size 5μ).

50 parts by weight of graphite fiber (Kuraray Carbon Fiber Chotsuzu average fiber length 6 m, average diameter 10 μm).

Polyvinyl alcohol 6-ti aqueous solution (Shin-Etsu Chemical 0-17)
45,000 and kneaded with a mixer.

After cross-mixing, the sample was granulated into spheres with a diameter of 10 cm and dried in a dryer at a temperature of 90@0 for about 1 hour to solidify the sample.

Next, this sample was heated in an electric furnace at 1450°C in a nitrogen atmosphere.
'0. The sample was fired for 5 hours to react, and the solidified sample was ground in a mortar. The reaction product obtained by pulverization had 810 short fibers uniformly dispersed in a fine powder matrix.

The reaction product was then dispersed in water and passed through a filter to separate powder particles and fibrous material.

According to X-ray diffraction, the particle powder contains α- and I-818N
4 S#! The fiber was p-5to. The average fiber length of the obtained fibers was 200μ.

Example (2) Silica powder (Nihon Silikani Gyo Co., Ltd., Nibcil ■,,
100 parts by weight of average particle size 14 mA, 8101941G) and flame-resistant fiber (Toho Rayon, chopped).

average fiber length 5■, average diameter 15-15μ) 6O parts by weight, Metrose 1s aqueous solution (Shin-Etsu Chemical 908H3oooo
) 45,000, and '! , knead with a kisser.

As in Example (1), 1 in an argon atmosphere in an air furnace.
70060 for 2 hours to obtain a reaction product with fibers uniformly dispersed in the powder matrix.

According to X-ray diffraction, the reaction product was found to have 0 β-characteristics for both powder and fiber. The average fiber length of the obtained fibers is 2
It was 50μ.

Example (3) 80 parts by weight of silica powder, 50 parts by weight of ethyl silicate (Colcoat Co., Ltd., silica content 401G), 60 parts by weight of Kynol fiber (Japan Kynol Co., Ltd., average fiber length 3cm, average diameter 9-11μ) and Metrose 1-aqueous solution 45,000.

The mixture was kneaded in a mixer, and fired in a 4-air furnace at 1650°C for 5 hours in an argon atmosphere in the same manner as in Example (2) to obtain a reaction product in which the fibers were uniformly dispersed in powdered Mal-IJ lux. Ta.

According to X-ray diffraction, the reaction product had a particle size of /-810 for both powder and fiber. The average fiber length of the fibers was 250μ.

Effects of the Invention According to the present invention, it is possible to produce a silicon carbide or silicon nitride powder-based material in which silicon carbide short fibers are extremely uniformly dispersed.

It is promising as a raw material for producing fiber-reinforced composite ceramics.

Further, the silicon carbide short fibers can be easily separated,
It is promising as a raw material for various composite materials (for example, fiber-reinforced metals).

In addition, according to the present invention, an inexpensive method for producing silicon carbide short fibers can be provided.

Claims (13)

[Claims] (1) An organic substance and/or an inorganic substance containing a silicon component and an organic fiber or carbon fiber are bonded with an organic binder and brought into contact with each other, and this is fired in a non-oxidizing atmosphere to form silicon carbide or carbon fiber. A powdered fire-resistant material in which short silicon carbide fibers produced by reaction of carbon fibers are uniformly dispersed in a silicon nitride powder matrix. (2) The material according to claim 1, wherein the organic substance is ethyl silicate or polycarbosilane. (3) The material according to claim 1, wherein the inorganic substance is metal silicon powder, silica powder, colloidal silica, SiC, Si_3N_4, or SiCl_4. (4) The material according to claim 1, wherein the organic fiber is polyvinyl alcohol, polyacrylonitrile, nylon, Tetoron, or viscose rayon. (5) The material according to claim 1, wherein the carbon fiber is carbon fiber itself, graphite fiber, flame-resistant fiber, infusible fiber, or kynol fiber. (6) The material according to claim 1, wherein the organic binder is polyvinyl alcohol, polyethylene oxide, CMC, or Metrose. (7) Short silicon carbide fibers separated from a matrix of silicon carbide or silicon nitride powder particles. (8) Silicon carbide or silicon nitride powder made by mixing, granulating, drying, calcining, and pulverizing organic and/or inorganic substances containing silicon components, organic fibers or carbon fibers, and organic binders. A method for producing a powdered fire-resistant material in which short silicon carbide fibers produced by reacting carbon fibers are uniformly dispersed in a particle matrix. (9) The method according to claim 8, wherein the organic substance is ethyl silicate or polycarbosilane. (10) The inorganic substance is metal silicon powder, silica powder, colloidal silica, SiC, Si_3N_4, SiCl_4
The method according to claim 8. (11) The method according to claim 8, wherein the organic fiber is polyvinyl alcohol, polyacrylonitrile, nylon, Tetron, or viscose rayon. (12) The method according to claim 8, wherein the carbon fiber is carbon fiber itself, graphite fiber, flame-resistant fiber, infusible fiber, or kynol fiber. (13) The method according to claim 8, wherein the organic binder is polyvinyl alcohol, polyethylene oxide, CMC, or Metrose.