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Alumina fiber reinforced alumina closed-cell foamed ceramic and preparation method thereof

A technology of closed-cell foam ceramics and alumina fiber, applied in the field of foam ceramics, can solve the problems of poor uniformity of pore distribution, powdering and peeling of porous ceramics, and high foaming temperature, so as to reduce slag and pulverization and improve heat preservation Thermal insulation performance, evenly distributed effect

Active Publication Date: 2016-05-04
JIANGSU HIGH TECHNO THERMAL EQUIP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The shape and distribution of pores in foam ceramics depend on the shape and distribution of the pore-forming agent. The advantage is that foam materials with complex shapes and different pores can be obtained. The disadvantage is that the distribution of pores is not uniform.
Patent No. CN104311118A discloses adding polysaccharide organic foaming agents and sintering aids to the ceramic powder, and after foaming and solidifying at 120~180°C, it is fired to produce ultra-light alumina foam ceramics. The disadvantage is that the content of polysaccharides is added High, high foaming temperature
In addition, the process of preparing porous ceramics by foaming method is also prone to powdering and peeling.

Method used

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  • Alumina fiber reinforced alumina closed-cell foamed ceramic and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Take 50ml of tetraethyl orthosilicate (TEOS) and 20ml of ethanol (EtOH) and mix it as A solution; add 6ml of concentrated nitric acid (HNO 3 ) and 6ml of glacial acetic acid (HAc) as liquid B; slowly inject liquid A into liquid B while stirring, and after standing for 0.5 to 1 hour, it will be silica sol, and the prepared silica sol has a small particle size and a large diameter distribution. Narrow, stable performance, can be stored for more than 20h.

[0028] Put the alumina gel fiber into the muffle furnace, raise the temperature from 100°C to 500°C at a rate of 2°C / min, and keep it warm for 0.5~1h, so that the gel fiber is completely carbonized, and after cooling in the furnace, it is broken into 3~ 5mm staple fiber.

[0029] Take 30wt% alumina short fibers and 55wt% α-Al 2 o 3 Powder, add graphite powder 2.0wt%, carboxymethyl cellulose 1.0wt%, polyacrylamide 1.0wt%, kaolin 2.0wt%, silica sol 6.0% and appropriate amount of distilled water, fully mix and stir to o...

Embodiment 2

[0034] Dissolve 30g of anhydrous aluminum chloride in 500ml of water, then put it into a reaction kettle with 30.3g of aluminum micropowder, heat and reflux at 90~100°C for 2~3h, and filter to obtain aluminum sol (Al 2o 3 The mass fraction is about 12.1%). Its zeta potential value is about 35mV, and it can be stored stably for more than 3 days.

[0035] Take 20wt% alumina short fibers and 60wt% α-Al 2 o 3 Powder, add calcium sulfate dihydrate 2.0wt%, carboxymethyl cellulose 1.0wt%, polyacrylamide 1.0wt%, aluminum sol 8wt%, bentonite 3.0wt%. After adding an appropriate amount of distilled water, fully mix and stir to obtain a slurry with certain rheological properties. After adding 5.0 wt% hydrogen peroxide solution, heat and stir at 70°C for 40s until the slurry foams.

[0036] Before the foam collapsed, the above slurry was injected into a preformed non-porous mold to obtain a wet billet, which was transferred together with the mold to a constant temperature and humidity...

Embodiment 3

[0040] Take 15wt% alumina short fibers and 65wt% α-Al 2 o 3 powder, and add 2.0wt% of calcium sulfate dihydrate, 1.0wt% of polyacrylamide, 5.0wt% of aluminum sol, 6.0% of silica sol, 3.0wt% of bentonite and appropriate amount of distilled water, and then fully mix and stir to obtain certain rheological properties slurry. After adding 3.0% calcium carbonate, heat and stir at 70°C for 20s, the acidic silica sol reacts with calcium carbonate, and the slurry foams and expands in volume.

[0041] Before the foam collapses, the above slurry is injected into a preformed non-porous mold to obtain a wet billet, which is transferred together with the mold to a constant temperature and humidity box and maintained at 75°C for 0.5h, and then the foaming is completed. After the green body is cured, it is removed from the mold, and then placed in a blast drying oven for 4.5 hours at 80°C to obtain a green body. The green body is heated at 3°C / min from 100°C to 950°C, held for 50 minutes, ...

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Abstract

The invention discloses alumina fiber reinforced alumina closed-cell foamed ceramic and a preparation method thereof. Service temperature of the alumina fiber reinforced alumina closed-cell foamed ceramic is lower than 1700 DEG C, compressive strength is 7 MPa to 10 MPa, heating permanent linear shrinkage under 1600 DEG C is less than 1.5 percent multiplied by 24 hours, a heat conductivity coefficient of a hot surface of 1000 DEG C is 0.40 to 0.60 W / m.K, volume density is 0.7 to 1.0 g / cm<3>, and porosity is 75 to 83 percent; content of Al2O3 of chemical compositions is not less than 95 wt%; a principal crystalline phase of the foamed ceramic is alpha-Al2O3; a micro phase also comprises mullite produced by high-temperature reaction between silica sol and alpha-Al2O3. According to the alumina fiber reinforced alumina closed-cell foamed ceramic and the preparation method thereof disclosed by the invention, in a manner of combining pore-forming agent adding with a foaming method, the prepared foamed ceramic is of a closed-cell structure, and is high in porosity and has good mechanical property; the alumina fiber reinforced alumina closed-cell foamed ceramic can be used as a fire-proof insulating material, and is applied to the fields of high-temperature electric furnace linings, building materials and the like.

Description

technical field [0001] The invention belongs to the technical field of foam ceramics, and in particular relates to alumina fiber-reinforced alumina closed-cell foam ceramics and a preparation method thereof. Background technique [0002] Foam ceramics can be divided into closed-cell foam ceramics and open-cell foam ceramics according to the relationship between pores. Alumina foam ceramics are widely used in molten metal filtration, catalyst carrier, Thermal insulation materials and building materials and other fields. According to its application, there are also corresponding preparation methods. [0003] In the published paper "Preparation of Alumina Foamed Ceramic Filter by Polyurethane Template Method at Low Temperature", polyurethane sponge was used to impregnate the slurry made of alumina powder and aluminum dihydrogen phosphate to obtain the paste-coated green body, which was pyrolyzed at 800°C to prepare the alumina foam ceramic filter. Aluminum foam ceramic filte...

Claims

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Application Information

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IPC IPC(8): C04B35/10C04B35/80C04B38/02
CPCC04B35/10C04B35/803C04B38/02C04B2235/5224C04B2235/5276C04B2235/96C04B38/0067
Inventor 刘和义乔健崔宏亮张敏
Owner JIANGSU HIGH TECHNO THERMAL EQUIP CO LTD
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