JPS62171973A - Fiber porous refractories 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] [Industrial Application Field] The present invention relates to a heat insulating material for high temperature, a filter for highly wet fluids,
The present invention relates to a method for producing a porous refractory made of ceramic fiber used as a catalyst carrier, metal reinforcement, etc.

[Conventional technology]

A7! Fibers obtained by molding and sintering O-B 0-3j-0 fibers 2g 23 2 Porous refractories are used by the National Aeronautics and Space Administration in space shuttles and the like, and are well known. These fibers can fuse the contact areas between the fibers by heating without using a binder, making it possible to form a high-strength fibrous porous refractory. However, this fiber is very expensive and cannot be used as a general industrial material that requires economy.

For general industrial use, Aj 0-8j○ fibers, A, 1 O fibers, and SiO fibers are dispersed in water together with an inorganic binder such as silica sol or alumina sol, vacuum formed, dried and fired, and the fibers between the fibers are A fibrous porous refractory made by fusing SiO, 81203 is used for the contact portion. However, this product has no strength, and the bending strength is J-89503-1.
9695.7 Bending strength, Nyoru.

The same applies hereinafter) has 2 to 4 ψ points and does not have sufficient strength to withstand handling. Phosphoric acid other than silica sol and alumina sol,
If water glass or the like is used as a binder, it will deteriorate the fibers.
Heat resistance and strength decrease.

A fibrous porous refractory has also been proposed in which Al2O3 fibers, 5102m fibers, and boron oxide are dispersed in water, vacuum formed, dried and fired, and the contact areas between the fibers are fused with boron oxide.

In this case, boron oxide (BO) has deliquescent properties and reacts with water to form boric acid, which dissolves in water (solubility 4 g/10
0 m120 r), it remains in the water during vacuum forming and becomes a loss, and what adheres to the fiber also sublimates and dissipates during drying and firing, during the process of changing to BO through metaboric acid and tetraboric acid. do. This varies slightly depending on the temperature of the dispersion medium water, drying and firing conditions, and the amount of adhesion to the fibers is not constant.
In some cases, the strength of the obtained fibrous porous refractory is There is a problem that is not constant.

[Problem that the invention seeks to solve]

The present invention aims to provide a fibrous porous refractory made of one or both of Al0-SiO2 fibers and SiO fibers and having stable strength, and an economically stable method for producing this refractory. purpose.

[Means for solving problems]

In order to achieve the above object, the present invention uses Al O-3in2
A porous refractory made of fibers, a porous molded product made of one or both of fibers and SiO fibers, in which the contact portion of the fibers is fused with a nitrogen- and boron-containing glass, and Al o -51o
＠fiber, S10 fiber and one or both of them and Al, Si, B, O, N or Si which does not dissolve in water and can be heated.

Boron nitride or nitrogen compound and boron compound powder forming a glass network structure consisting of B, O, and N are dispersed in water, vacuum formed, and the formed product is fired and sintered to obtain a fibrous porous refractory. It is in.

AIM is a nitrogen compound that can be used in the present invention.

Si3N4.5i-Aj-0-N, 5i2N20.0
a3N2. Li3N.

Examples include Mg N and the like. In addition, boron compounds include B, O, TiB2.0rB2. TaB2.
MnB2. MoB2°VB2. HfB2. AtB
2. MgB2. ZrB2. W2B,, Mo2B
5 and the like, and any nitrogen compound or boron compound may be used as long as it does not deteriorate the material fiber.

If the particle size of boron nitride or the above compound powder is too small, when drying a vacuum-formed product, the particles will migrate to the surface with water and stick to the drying plate, making it difficult to remove and often impairing marketability. Also, if the particle size is too large, it will shift to one side during vacuum forming and the sintered state will become uneven.
A particle having a particle size distribution of m is used.

The boron compound powder used is 2 to 7 parts by weight in terms of B12 a per 100 parts by weight of fiber. If the amount is less than 2 parts by weight, sinterability will be insufficient, and if it is used in an amount exceeding 7 parts by weight, the strength will no longer improve after sintering, and unreacted boron compounds will remain in the sintered body. As a result, the strength of the product decreases when reheated.

When using a mixture of nitrogen compound powder and boron compound powder instead of BN, it is preferable to use them so that the number of B atoms and N atoms is in a ratio of 1=1.

The fiber length is 30 to 1! 11. Most of them have a length of 5 to '7+, and approximately 10 parts by weight or less per 100 parts by weight of water is dispersed in water, boron nitride powder or nitrogen compound powder and boron compound powder are added, and an organic flocculant is added. , vacuum forming, drying, 1-1 at 1250-1400C
．． It is fired for 5 hours and sintered to produce a fibrous porous refractory.

[Effect]

When the boron nitride powder or the nitrogen compound powder and the boron compound powder dispersed together with the fibers in water are dried after vacuum forming, they are mainly deposited at the contact area between the fibers due to capillary action. When these dry and deposited powders are heated to high temperatures, they react with A, lO1S10 in the fibers, forming nitrogen-containing aluminoborosilicate glass or nitrogen-containing f-borosilicate glass, and forming At, Si, B, O, N, or S.
A glass network structure of L, B, O, and H is formed to firmly bond the contact portions of the fibers. Since these compounds remain in the molded body during firing until they are decomposed or sublimated at high temperatures, they can be used to bind fibers more efficiently than when BO is used.

〔Example〕

Example 1 A/' O-3i of 1.00 parts of water and 0 parts of electricity
O fiber (trade name Kaoh-ru manufactured by the applicant) and B2O
After dispersing 1 to 15 parts by weight of BN in water, adding an organic flocculant, vacuum forming, drying,
．． It was sintered by firing at 370 C for 1 hour.

Bending strength test pieces were prepared from the sintered bodies and their strengths were compared.

The results are shown in Table 1.

Example 2 Unsuitable as a tabular high-temperature insulating material Example 2 Sintering was carried out in the same manner as in Example 1, except that BC and SiN were used in place of BN so that the number of B atoms and N atoms was approximately 11. The results of forming and testing solids are shown in Table 2.

Table 2 ．． 46 part , Suho.

Characteristic Deterioration Comparison Example Except for using BO instead of BN in Example 1,
A sintered body was made and tested in the same manner as in Example 1. The results are shown in the third example.
It was as shown in the table.

Table 3 [Effects of the invention] Instead of BO, boron nitride, which does not dissolve in water and forms nitrogen-containing aluminoborosilicate or nitrogen-containing borosilicate glass in coexistence with silica, or a nitrogen compound and a boron compound powder is used. By doing so, it is possible to economically produce a fibrous porous body that is more stable and strong than when using BO.

Claims (4)

[Claims] (1) A fibrous porous refractory in which the fiber-to-fiber contact areas of a porous molded product made of one or both of Al_2O_3-SiO_2 fibers and SiO fibers are fused with nitrogen- and boron-containing glass. (2) One or both of Al_2O_3-SiO_2 fibers and SiO_2 fibers and Al, S which does not dissolve in water and can be heated
Powders of boron nitride or a nitrogen compound and a boron compound forming a glass network structure consisting of i, B, O, N or Si, B, O, N are dispersed in water, vacuum formed, and the molded product is fired. A method for producing a sintered fiber porous refractory. (3) Boron nitride, nitrogen compound, and boron compound powder have an average particle size of around 10 μm, and 80% by weight or more has a particle size of 1 to 44 μm.
The method for producing a fibrous porous refractory according to claim (2), which has a particle size distribution of m. (4) The fiber according to any one of claims (2) and (3), in which boron nitride or a nitrogen compound and boron compound powder are used in an amount of 2 to 7 parts by weight in terms of B_2O_3 per 100 parts by weight of the fiber. Method for manufacturing porous refractories.