RU1774521C - Heat-resisting material - Google Patents

Abstract

The invention relates to heat resistant materials of various compositions. The material contains (wt.%); carbon fiber 49-58, polymer binder coke 10-20, pulverized graphite 10-20, pyrocarbon 31-2. The fraction of graphite crushed no more than 90 microns. The use of the invention consists in the preparation of a binder with graphite ground, the manufacture of a prepreg with a carbon fiber filler, followed by the steps for producing a carbon-carbon material. The size of delaminations in articles made of material is reduced by 9-19 times.

Description

The invention relates to electrical materials used under high temperature conditions, as well as non-metallic heat-resistant materials for the chemical, aviation, metallurgical industries.

Heat-resistant material is known (ed. St. Mg 792612, class N 05 B 3/14, 1978). Its disadvantages: low strength and a high level of delamination in the manufacture of plates, cylinders and other various products of geometric shapes.

The closest technical solution, selected as a prototype, is the material (ed. St. No. 1489560, class N 05 B 3 / 14.1987), which in terms of the composition of the components contains pyrographite powder fraction of not more than 60 microns, and the components are taken in the following ratio, wt.%:

Carbon fiber

Coke Polymer

Binder 14-25

Pyrographite 3-15

Pyrocarbon

The disadvantage of this material is the high level of delamination of products of complex shapes and large thicknesses from this material. The cost of the products received is high. In this case, there is a large difference in thickness of the material (for example, in the manufacture of plates), which reduces its quality indicators, for example, increases the spread in the values of electrical resistance in the manufacture of electric heaters. The disadvantage of the material is the high cost of producing pyrographite, including the manual peeling of pyrographite from the surface of the furnace and tooling, as well as a high degree of crushing of the material (a fraction of 60 microns is required), which increases its cost.

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The purpose of the invention is to reduce delamination of the material.

To achieve this goal in a known heat-resistant material, which includes carbon fiber, coke polymer binder and pyrocarbon, instead of a powder of pyrographite fraction not more than 60 microns, according to the invention, graphite is crushed fraction not more than 90 microns, and the components are taken in the following ratio, wt.%: Carbon

fiber49-58

Polymer Binder Coke 10-20

Graphite

crushed 10-20

Pyrocarbon

The use in the material of filler from graphite crushed with a lower coefficient of thermal expansion (see Nagorny V.G. et al., Properties of carbon-based structural materials. Handbook. Ed., V.P. Sosedova, M .: Metallurgists, 1975 , p. 121-128) reduced shrinkage phenomena in the operations of pressing, carbonization and heat treatment, which led to a decrease in delamination by 9-19 times.

A decrease in shrinkage in the matrix during carbonization also occurs due to crushing of the interlayer layers of the polymer matrix with an increased content (in comparison with the prototype) of the dispersed filler from graphite,

The lower hardness of the crushed graphite filler obtained at 2 ° C-3000 ° C does not injure the carbon fiber and does not reduce the strength characteristics of the material.

The absence of manual peeling of pyrographite and the use of crushed graphite of larger fractions, which require less grinding, reduces the cost of the material.

Comparison with the prototype allows us to conclude that the claimed material differs from the known one by the introduction of a new component with different parameters of the crystal structure and physico-mechanical properties, namely: graphite of the crushed fraction is not more than 90 μm, and the components are taken in the following ratio of the fraction more than 90 microns, and the components are taken in the following ratio, wt.%: Carbon

fiber 49-58 Coke polymer binder 10-20 Graphite

crushed 10-20

Pyrocarbon

Thus, this technical solution meets the criterion of novelty

An analysis of known materials both in this field and in other fields showed that some components and the ratio of components in materials introduced into the claimed solution are known.

0 for example carbon fiber, 49-58 wt.%; polymer binder coke; carbon particulate filler and pyrocarbon. However, their use in these materials does not provide the material with the properties that are manifested in the claimed solution, namely, the reduction of delamination. Thus, the introduction of a new component into the material with different crystal structure parameters

0 and physico-mechanical properties give the material new properties, which allows us to conclude that the solution meets the criterion of significant differences.

Heat Resistant Manufacturing Options

5 materials are shown in the examples.

Example 1. An electric heater is made with dimensions, mm: length 1100, width 550, thickness 6. As a carbon filler, a carbon filler is used

0 TGN-2M fabric (TU 48-19-20-77), SF-010 phenol-formaldehyde resin (GOST 18694-80) as the binder. The graphite electrode production (TU 48-20-54-84), crushed to a fraction of 90 μm or less, is introduced

5 to resin SF-010 in an amount of 25%. The powder resin is thoroughly mixed until a uniform suspension is obtained. The resulting suspension is poured into the bath of an MPT-3 impregnation machine. Across

0 impregnation bath pass carbon fabric and simultaneously squeeze squeezing rollers. This ensures that the suspension is uniformly applied over the entire surface of the fabric. After drying the fabric, half of the learned prepreg is cut into pieces of 1100 x 550 mm in size. Pieces are put in a package with a height of 6.5 mm. The final curing of the bag occurs at a pressure of 80 kg / cm2 and a temperature of 160 ° C. The package is carbonized in a neutral medium at 850 ° С and a temperature rise rate of 3–6 ° С. Then, the material is subjected to heat treatment at 1900–2000 ° С in an electric furnace, and then pyrocarbon in the amount of 14–16% is deposited into the pores of the obtained workpiece by treatment in methane at 975–1000 ° С for 100–120 h.

Example 2. Make an electric heater with dimensions, mm: length 830, width 430, thickness 10. As

carbon filler using fabric URAL-T22 (GOST 28005-88), as a binder mixture of the following components, parts by weight:

Resin SF-010

(GOST 18694-80) 100

Ethanol

(GOST 18300-73) 80-100

Urotropin

(GOST 1381-73) 12.5

In the binder of 80–10 s in the binder, according to the VZ-246 viscosity meter (GOST 9070-75).

The fabric is passed through an MPT-3 type impregnation machine to produce a prepreg. The resulting prepreg from the fabric contains 33-36% binder. It is cut into pieces of predetermined sizes and put into a bag. The number of fabric layers is 20. Each fabric layer is sprinkled with graphite powder of crushed (TU 48-20-54-84) fractions of not more than 90 microns, flow rate 0.04 g per 1 cm. The powder layer is leveled with a special template over the entire surface of the fabric layer. Further processing packets are carried out according to the mode of example 1.

Example 3. A disk is made for the screen of an electric furnace with the dimensions, mm: diameter 500, thickness 30. URAL-T22P carbon fabric (GOST 28005-88) is used as a carbon filler, and a mixture is used as a binder (see Example 2). After preparation of the prepreg, a bag of 60 layers of fabric was assembled. Each layer is sprinkled with graphite crushed (TU 48-20-54-84) fractions of not more than 90 microns. Further processing of the package is carried out according to the mode of Example 2.

Example 4. A screen is made for the bottom of an electric furnace with dimensions, mm: diameter 1500, thickness 40. The carbon fabric TGN-2M (TU 48-19-20-77) is used as a carbon filler. A mixture is used as a binder (see Example 2). After preparation of the prepreg, a packet of 78 layers of fabric is drawn. Upon preparation of the prepreg, crushed graphite (TU 48-20-51-84) fractions of not more than 90 microns are introduced into the bath with a binder. Graphite consumption

crushed per 1 kg binder 0.1 kg. The final curing of the resulting package occurs in an autoclave at a pressure of 10 kg / cm and a temperature of 160 ° C. Further processing of the package is carried out according to the mode of example 1.

Example 5. A reactor cover is made for pyro-sealing in a vacuum furnace of large-sized products with the following dimensions, mm: diameter 2200, thickness 25. URAL-T22 fabric (GOST 28005- 88) is used as a carbon fiber filler, crushed graphite as a carbon dispersed filler ( TU 48-20-16-81) fractions no more than 90 microns. The number of fabric layers in the bag is 54. All operations for obtaining material are carried out according to the modes of Example 4.

In the table. Figure 1 shows the effect of crushed graphite of various grades on the properties of heat-resistant material and products.

The composition and properties of the obtained material, as well as the prototype (products and mode of examples 1-3 with pyrographite fraction of not more than 60 microns and pyrographite content of 8.8 wt.%) Are given in table. 2 and 3.

As follows from the data presented in table. 1-3, the delamination in the products of the heat-resistant material proposed in the application decreased by 9-19 times. The thickness of the products decreased by 3-5 times.

Claims (1)

The claims Heat-resistant material based on carbon fiber, coke polymer binder, pyrocarbon and carbon dispersed filler, characterized in that, in order to reduce delamination in the material, it contains graphite crushed by a fraction of not more than 90 microns, and the components are taken in the following ratio, wt.%: Carbon fiber Coke Polymer Binder 10-20 Graphite crushed 10-20 Pyrocarbon -j -4 w SP GO 3.7 1.2 1.0 0.7 0.3 0.5 0.4 2.5 2.7 M table 2 COMPOSITION OF HEAT-RESISTANT MATERIAL MATERIAL PROPERTIES Table 3