JPS5969461A - Sintered porous ceramic product - 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 to which the invention relates] This invention relates to a sintered porous ceramic molded body.

PRIOR ART The production of porous ceramic materials from mixtures based on wollastonite (calcium silicate), aluminum hydrogen phosphate and water is already known from US Pat. No. 314,899 (3); Drying and firing ceramic materials prepared by base systems has proven to be extremely tedious. Extensive drying cracks are common in the product, and in some cases the product may tear during sintering. There is one thing.

Due to this problem, we have avoided sintering this product until now, but the strength of the dried product is too low to be of commercial value.2) Many have to be discarded due to cracking during drying. there were.

Therefore, the acid-base method according to the above US patent has not resulted in a product of any commercial value.

It is extremely necessary to be able to manufacture this sintered porous ceramic material for use in heat and sound insulation at high temperatures. Thus, sintered ceramic materials have several characteristics, such as being able to withstand high temperatures and being not attacked by common chemicals that normally strongly corrode other materials.

[Disclosure of the invention]

The problems caused by the known acid-base method described above are solved by the present invention, and a sintered porous ceramic molded body is provided.

The molded body is manufactured from a composition consisting of the following components:

(1) One or more basic materials such as calcium silicate and/or calcium aluminate.

(2) An aqueous solution of one or more compounds represented by the following formula.

XAl2O3・yP205. zH20 However, 0.3 work x 9.1 work y≦turn 1 work 2≦10, preferably x-1, y-3, z = 3° (3) Clay is kaolin.

(4) Feldspar (5) Silica and/or aluminum phosphate.

(6) Voluntary water.

This composition is dried into a molded body and finally sintered, but before hardening, the composition is hardened by a chemical reaction with air bubbles inside to form a porous molded body.

This composition cures at room temperature by a chemical reaction depending on the contents of components +1) and (2). This usually occurs within 30 minutes after incorporation of the ingredients, so there is no need for external heat to be supplied.

According to a suitable embodiment of the invention, component (1) consists of wollastonite, which reacts with component (2), an aqueous aluminum hydrogen phosphate solution. This aluminum hydrogen phosphate aqueous solution is stoichiometrically converted into aluminum hydroxide AZ(OH
)3 in 85% orthophosphoric acid H3PO4.

7u+(OH)3+3H3P04→AI! (H2PO4
), +3H20+heat In most cases, water is added to the solution after the reaction to prevent the viscosity of the final mixture from becoming too high.

Wollastonite is a calcium silicate that reacts with basicity, and in the chemical reaction that occurs when the composition hardens, calcium ion penetration results in the precipitation of AJ (H,, PO4) and calcium phosphate. Calcium aluminate or a mixture of calcium silicate and calcium aluminate may be used instead of calcium silicate.

Ingredients (3), +4), +5] enable the composition to dry and bake without problems like X' porcelain paste.

In one embodiment of the invention, component (3) comprises clay;
Component (5) consists of quartz (silica), and forms glass eyes when sintered together with the feldspar of component (4). this glass
['4 binds crushed stone feed such as quartz to form extremely strong bonds between particles. The best feldspar is potassium feldspar.

Amorphous 5 such as 5i02 with a different crystal shape instead of quartz
102 can also be used, as well as some or all of the silica can be replaced with aluminum phosphate, as in the case of 2 series.

In the glass phase, phosphoric acid triquartz Ca3 (PO
4) 2 is formed.

The temperature of the molded body is 800 to 1500°C, and the temperature is 100°C.
It is sintered by firing at 0 to 1300°C.

The proportions of the various components of the compositions used in the production of ceramic molded bodies according to the invention can vary within a wide range, but are typically as follows.

(1) Calcium silicate and 7-year-old calcium aluminate 10-65, Shibashikuba 10-40, Kosun-shikake 2
0-65% by weight.

(2) One or more compounds of the following formula -5 to 40% by weight.

x Al2O2-y P2O,, z H20<<<<
<< However, 0.3=x=3. , I=y=6, I=z==
IJ preferably x-1, y-3, Z-3° (3)
Clay still contains 5 to 30% kaolin by weight.

(4) 1-10% by weight of feldspar.

(5) Silica and/or aluminum phosphate 10
~40% by weight 0 or less'' Calculated based on the dry state of the composition.

Other methods can also be used to obtain porous molded bodies according to the invention. For example, fermentation methods can be used and fermented All may be added to obtain the desired porosity.

Injection of air or stirring with a blowing agent is also an effective method. It is also appropriate to use gas generating agents, examples of which include carbonates such as magnesium carbonate, and metals such as aluminum and iron.

It has been found that adding a foaming agent and a foam stabilizer to a carbonate additive, such as basic magnesium carbonate, and stirring vigorously creates a good cellular structure within the molded body.

The volume and size of the cells can be changed by changing the foaming method.

The foaming method to be used is not an important aspect of the present invention, but it is considered necessary in all cases that the required cell tissue be formed by the time the composition is completely cured.

It may be appropriate to add surfactants to the composition.

The compact before sintering is 11 inches long and extremely strong, so it can be transported on a belt or stacked in a furnace or on a stand without any problems.
It can be used without sintering because it has very high mechanical and chemical strength. However, after sintering, the properties of the porous compact become significantly better. In other words, it not only has excellent mechanical properties but also exhibits extremely high resistance to chemicals and other corrosive substances.

Second, this molded body has excellent sound absorption and heat insulation properties.

The molded article according to the invention has many features and can be used for various purposes. For example, molded bodies of one size or more can also be used as sound-absorbing parts for automobile silencers. Of course, this molded body mouth can be used for the purpose of absorbing sound in curves, but it can also be used for other purposes such as building blocks, filters, and various heat insulating materials.

[Embodiments of the invention]

Next, the present invention will be described with reference to examples showing methods for producing sintered porous molded bodies using various compositions.

example! AI! (oH) 3156g, 85% phosphoric acid 400m/
E, L: Mix 800 g of quartz with 800 g of aluminum hydrogen phosphate solution prepared from 200 g of water and prepare the following A.
I made a mixture called a mixture. 400g of calcined wollastonite,,
200 g of uncalcined wollastonite, 500 g of icy clay, 150 g of potassium feldspar, % basic magnesium carbonate (MgC0
30 g of 3-Mg(OH)-3H20), 800 g of water, and 0.5 g each of foaming agent and foam stabilizer were thoroughly mixed to prepare a mixture hereinafter referred to as mixed liquid B.

While stirring strongly, add A/f to the B mixture! After injecting the liquid and stirring for 1 minute, the mixture was placed in a mold and molded. After 20 minutes, the molded cermet was removed from the mold, covered, and heated for 24 minutes.
It was kept at room temperature for an hour. Next, this one-sew-knot foam was dried in a drying chamber for two hours, during which time the relative humidity in the drying chamber was gradually lowered from 100 degrees to f degrees.

The molded body of the final example was fired at 1260±15°C to obtain a sintered porous molded body.

Example 2 Calcined wollastonite 300g, uncalcined wollastonite 300g, Clay 5
00g.

Potassium feldspar 150g, basic magnesium carbonate 40g
1. 850 g of water and 0.5 g of surfactant are thoroughly mixed to make a mixture hereinafter referred to as C mixture. While vigorously stirring, 1600 g of mixed solution A from Example 1 was poured into the mixed solution C, and after stirring for 1 minute, the mixture was placed in a mold and molded. The thus obtained nohi sament molded body was taken out of the mold, covered, and kept at room temperature for 24 hours. Next, this foamed cermet U-shaped body was dried in a drying chamber at 80°C for 90 hours, during which time the relative humidity in the drying chamber was gradually increased from 100% to 10%.
reduced to %. Finally, the molded body is fired at 1240±15°C to produce a sintered porous molded body.

Example 3 Calcined wollastonite 1385g, Uncalcined wollastonite 1115g,
, length 7'' 50g, viscosity 2400g, basic magnesium carbonate 200g, water 3750g and surfactant 58 are thoroughly mixed to make a mixture hereinafter referred to as mixed liquid.
. While stirring strongly, add the A mixture '7500 of Example 1 to this D mixture.
After stirring for 1 minute, the mixture was put into a mold and molded. After 20 minutes, the thus obtained molded product was removed from the mold, coated, and heated to room temperature for 24 hours.
I was stunned after thinking about it. Next, this foamed dermet molded material was dried at 50'C for 120 hours in a Kurimuro laboratory, and during this time the relative humidity of the Kurimuro was successively adjusted from 100% to +o%. It's Fkj. Finally, the molded body is 1290±1
It is easy to set after baking at 5°C).

Obtain form/ξ.

Example 4 A l (OH) s + 56 g N 85
% phosphoric acid 350ml1. %" Yohi: J (250g of prepared aluminum hydrogen phosphate m ~ 800g of quartz
Mix B and call it the I:E mixture. F' 600 g of wollastonite, 600 g of clay, 600 g of clay, 25 g of magnesium carbonate.
g1 900 g of water and 0.5 g each of a foaming agent and a foam stabilizer were sufficiently mixed together to prepare the following mixture of Fγ kombu liquid and Kofu. Stir strongly t<+: Shitsuto's F r'J! Mixture E was poured into the solution, and after stirring for 1 minute, the mixture was put into a mold and molded. 20 minutes later Ij like this! 12. Nosugishi/Kozu-
-7 pieces were collected from the mold, cut and kept at room temperature for 24 hours. Next, this foamed Voux Mesotho molded body was dried in a drying chamber at 75.C for 95 hours, during which time the relative humidity in the drying chamber was adjusted to 100%, 75.degree.
I got an F. Finally, this molded body was fired at 1250±15°C to obtain a sintered porous molded body.

The present invention is not limited to the above embodiments, but may be modified in various ways within the technical scope thereof.

Claims (1)

[Scope of Claims] (1) One or more basic forms such as calcium silicate and/or calcium aluminate <<
<<'<< Machine and 0, 3 = x = 3, I = y =
6.1=z=io, preferably x=l, y=
3. When z=3, the formula xAe203・yP206. z
It contains an aqueous solution of one or more compounds given by H20, clay or kaolin, feldspar, silica and/or precipitated aluminum phosphate, and optionally water, with air bubbles inside before curing. The invention is characterized in that it is manufactured by using a composition that can be hardened into a porous molded body through a chemical reaction in a form that contains it, and then drying the resulting molded body and finally sintering it. Sintered porous ceramic molded body. Toshidatoki formula x Ap,,05・yP,,05. zH,
, an aqueous solution of one or more compounds given by O, clay, potassium feldspar, silica, and optionally water,
If it's 1st grade, it's more carbonate than AI! a gas-forming additive such as a metal such as Fe;
A sintered porous ceramic molded article characterized in that it is produced by drying the molded article thus produced and finally sintering it. +31 The molded article according to claim (1) or (2), characterized in that the composition of item 1 is cured by a chemical reaction without external heat supply. (4) Temperature: 800-1500 °C, preferably 1000~
The molded article according to claim +1), (2) or (3), which is sintered at 1300°C. (5) Claim (+), (2), (31) or (
4) The molded article described above. (6) Calcium silicate and calcium aluminate 10-65% by weight, preferably 20-65% by weight,
Preferably 1~< is the formula XAl2O5 when x=l'ty=3 and z=3. yP20. - 5 to 40% by weight of one type given by H20 or more, 5 to 30% by weight of kaolin for clay, 1 to 10% by weight of feldspar, and 10 to 10% of aluminum phosphate for silica and/or silicate. 40% by weight, all weight% calculated on dry matter, (2), (3)
, (4) still the molded article described in (5).