GB2168336A - A ceramic foam - Google Patents

A ceramic foam Download PDF

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Publication number
GB2168336A
GB2168336A GB08527211A GB8527211A GB2168336A GB 2168336 A GB2168336 A GB 2168336A GB 08527211 A GB08527211 A GB 08527211A GB 8527211 A GB8527211 A GB 8527211A GB 2168336 A GB2168336 A GB 2168336A
Authority
GB
United Kingdom
Prior art keywords
ceramic
ceramic foam
foam
micrometers
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08527211A
Other versions
GB8527211D0 (en
GB2168336B (en
Inventor
Yoshihisa Kato
Masashi Fujimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Coorstek KK
Original Assignee
Toshiba Ceramics Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP59260900A external-priority patent/JPS61141666A/en
Priority claimed from JP60042857A external-priority patent/JPS61201659A/en
Application filed by Toshiba Ceramics Co Ltd filed Critical Toshiba Ceramics Co Ltd
Publication of GB8527211D0 publication Critical patent/GB8527211D0/en
Publication of GB2168336A publication Critical patent/GB2168336A/en
Application granted granted Critical
Publication of GB2168336B publication Critical patent/GB2168336B/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
    • C04B38/0615—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B01D39/2068—Other inorganic materials, e.g. ceramics
    • B01D39/2093—Ceramic foam
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C04B35/111—Fine ceramics
    • C04B35/117—Composites
    • C04B35/119—Composites with zirconium oxide
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Porous Artificial Stone Or Porous Ceramic Products (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Filtering Materials (AREA)

Abstract

A ceramic foam for a metal filter or burner element has a three-dimensionally reticulated structure which consists essentially of Al2O3 70-95% by weight and ZrO2 5-30% by weight.

Description

SPECIFICATION A ceramic foam This invention relates to a ceramic foam having a three-dimensionally reticulated ceramic structure which can be used as a filter for molten metal moulding purposes, a heater and so on.
A ceramic foam has been used as such a type filter and a face type heater for a burner element. Such a ceramic foam is not pre-heated in a normal use mode. A good spalling resistance is required in order to avoid its breakage in view of plural repeated heating and cooling cycles.
If the conventional ceramic foams are used at a temperature of 130000 or less, a low heat expansion material such as a cordierite material can be used. At a high temperature more than 1300 C, such a material cannot be used, and materials which can resist repeated spalling tests are expected. In the past, however, no ceramic materials which can resist such repeated spalling tests are available.
The object of the invention is to provide a ceramic foam having an improved spalling resistance.
The present invention is a ceramic foam having a three-dimensionally reticulated ceramic structure composed of many interconnected ceramic strands and having continuous pores among the strands characterized in that the reticulated ceramic structure is composed of Al2O3 70-95% by weight and ZrO2 530% by weight.
Even if the ceramic foam is not preheated in use, it can satisfy a series of repeated spalling tests at a temperature of 13000C or more.
An embodiment of the present invention will now be described, by way of example.
As a ceramic material, an Al203-ZrO2 material is used, in which Awl203 70-95% by weight and ZrO2 5-30% by weight are mixed.
Preferably, the Al2O3 material is composed of small particles. The particle sizes of the Altos material range from 10 micrometers to 0.1 micrometers. The mean particle diameter thereof is between 5 and 0.5 micrometers. A ZrO2 material is preferably composed of small particles, the sizes of which range from 10 micrometers to 0.1 micrometers. The average particle diameter thereof is between 5 and 0.5 micrometers.
Such starting materials are mixed with water, a binder such as PVA and many balls such as ceramic balls within a ball mill so as to have a viscosity of 2-15 poise whereby a slip of slurry for the ceramic manufacturing purpose is prepared. A starting foam is a soft urethane foam which has a three-dimensionally reticulated structure composed of many interconnected strands and continuous pores among them. The soft urethane foam is plural times infused or impregnated with the above-mentioned slip. At each time the slip is dried to be hardened. In other words, the impregnating and drying steps are repeated a plurality of times.
The details of this point will be described. The soft urethane foam is infused or impregnated with the slip having a viscosity of 2-15 poise thereby to form a first layer on the surfaces of the strands of the urethane foam. Surplus slip is removed so as to avoid stopping thereof in the pores and dried to be hardened at a temperature of 50-100 C.
Also, a second layer is formed on the first layer by impregnating the first layer with same or different slip having a viscosity of 2-15 poise. Excess slip is removed so as to avoid stopping thereof in the pores and dried to be hardened at a temperature of 50-100 C.
In addition, a third layer is formed on the second layer by impregnating the second layer with same or different slip having a viscosity of 2-15 poise. Surplus slip is removed so as to avoid stopping thereof in the pores and dried to be hardened at a temperature of 50-100 C. The soft urethane foam is infused or impregnated with same or different slip, for instance, a few times. After that, it is dried to be hardened.
Each strand is increased in thickness thereby to have a multi-layer consisting of plural ceramic layers to such a degree that no surplus slip is stopped in the pores.
After that, it is fired at a temperature of 150000 or more so that the reticulated structure becomes a porcelain ceramic foam having a three-dimensionally reticulated ceramic structure composed of many interconnected ceramic strands. Also, the soft urethane foam is carbonized to disappear on firing. The ceramic foam has the characteristics as shown in Table 1.
As can be seen from Table 1, the bulk density of the ceramic foam is between 0.4 and 2.0. Cold crushing strength is between 50 and 100 Kgf/cm2. Bending strength is between 10 and 35 Kgf/cm2. It has a good strength as a whole.
Table 2 shows an example of spalling test results with respect to a ceramic foam according to this invention.
The spalling test herein means that the ceramic foam is repeatedly water-cooled down from a high temperature of 140000 in order to check how the ceramic foam is broken due to its temperature change.
In Table 2, the term "break times" means the number of spalling cycles until the ceramic foam is broken. As the value of break times increases, spalling resistance becomes better.
For instance, in cases of Al2O3 99% by weight, the ceramic foam is broken in one cycle or two cycles. In case of Al2O3 90% by weight and ZrO2 10% by weight having a mean particle diameter of 44 micrometers, it is broken in a few cycles.
On the other hand, in case of Al2O3 80% by weight and ZrO2 20% by weight having a mean particle size of 44 micrometers, the ceramic foam is broken in a few cycles.
However, in case of Awl203 90% by weight and ZrO2 10% by weight having a mean particle size of 5 micrometers, it is broken in five cycles if its bulk density is 0.3. If its bulk density is 1.0, then it is not broken even in 10 cycles. In case of Al2O3 80% by weight and ZrO2 20% by weight having a mean particle diameter of 5 micrometers, it is broken in 5 cycles if the bulk density is 0.3, but it is not broken even in 10 cycles if the bulk density is 1.0.
As can be seen from Table 2, a filter made of a ceramic foam material which can resist thermal spalling can have an improved spalling resistance by adjusting or selecting starting materials, composition ratios and particle sizes.
The spalling resistance is decreased if the ratio of Al2O3 is less than 70% by weight or more than 95% by weight, or if the ratio of ZrO2 is less than 5% by weight or more than 30% by weight.
As can be seen from the foregoing explanation, according to the invention, a ceramic foam is composed of Al2O3 70-95% by weight and ZrO2 5-30% by weight, and the spalling resistance is remarkably improved. Therefore, even if it is used as a ceramic filter for the molten metal moulding purpose in such a way that it is not pre-heated, it can have a long lifetime.
TABLE 1 Items Embodiment Chemical Composition Al2O3 - ZrO2 Bulk Density 0.4- 0.2 Crushing Strength (Kgf/cm2) 50 - 100 Bending Strength (Kgf/cm2) 10 - 35 Void Ratio (%) 85 - 90 Pore Diameter (mum) 1 - 2.5 Heat Resistance ( C) 1700 or more Apparent Porosity (Strands) 5% or less TABLE 2 Chemical Composition Bulk Density Break Times Awl203 99 % 0.3 1 1.0 2 Altos 90 %, ZrO2 10 % 0.3 2 (ZrO2: Mean Particle 1.0 3 Diameter 44 microns) Awl203 80 %, ZrO2 20 % 0.3 2 (ZrO2: Mean Particle 1.0 3 Diameter 44 microns) Al2O#90%,ZrO210% 0.3 5 (Partial Break) (ZrO2: Mean Particle 1.0 10 Diameter 5 microns) (No break) Al2O 80 %, ZrO2 20 % 0.3 5 (Partial Break) (ZrO2: Mean Particle 1.0 10 Diameter 5 microns) (No break)

Claims (8)

1. A ceramic foam having a three-dimensionally reticulated ceramic structure composed of many interconnected ceramic strands and having continuous pores among the strands characterized in that the reticulated ceramic structure is composed of Al2O3 70-95% by weight and ZrO2 5-30% by weight.
2. The ceramic foam of Claim 1, wherein the reticulated structure consists essentially of: an Awl203 material composed of small particles, particle sizes of which are between 10 micrometers and 0.1 micrometers, and the average particle diameter of which is between 5 and 0.5 micrometers; and a ZrO2 material composed of small particles, particle sizes of which are between 10 and 0.1 micrometers, and the average particle size of which is between 5 and 0.5 micrometers.
3. The ceramic foam of Claim 1, wherein each of the ceramic strands consists of plural ceramic layers.
4. The ceramic foam of Claim 2, wherein each of the ceramic strands consists of plural ceramic layers.
5. The ceramic foam of Claim 1, wherein a bulk density of the ceramic foam is between 0.4 and 2.0.
6. The ceramic foam of Claim 1, wherein a void ratio of the ceramic foam is between 85% and 90%.
7. The ceramic foam of Claim 1, wherein pore diameters of the pores are between 0.5 mm and 2.5 mm.
8. A ceramic foam as claimed in Claim 1 and substantially as hereinbefore described.
GB08527211A 1984-12-12 1985-11-05 A ceramic foam Expired GB2168336B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59260900A JPS61141666A (en) 1984-12-12 1984-12-12 Ceramic foam
JP60042857A JPS61201659A (en) 1985-03-06 1985-03-06 Ceramic foam

Publications (3)

Publication Number Publication Date
GB8527211D0 GB8527211D0 (en) 1985-12-11
GB2168336A true GB2168336A (en) 1986-06-18
GB2168336B GB2168336B (en) 1988-02-10

Family

ID=26382599

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08527211A Expired GB2168336B (en) 1984-12-12 1985-11-05 A ceramic foam

Country Status (2)

Country Link
DE (1) DE3540450A1 (en)
GB (1) GB2168336B (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5045511A (en) * 1990-02-26 1991-09-03 Alusuisse-Lonza Services, Ltd. Ceramic bodies formed from yttria stabilized zirconia-alumina
EP0466215A2 (en) * 1986-03-19 1992-01-15 Ceramiques Et Composites Filter for liquid metals, based on alveolar ceramic material, process for the production thereof, and its use in filtering liquid metals or alloys having high melting points
EP0471910A1 (en) * 1990-08-20 1992-02-26 Toto Ltd. Process for making a ceramic filter
US5110470A (en) * 1989-10-26 1992-05-05 Toto Ltd. Ceramic filter and process for making it
GB2260538A (en) * 1991-10-15 1993-04-21 Peter Gant Porous ceramics
EP0661247A1 (en) * 1993-12-20 1995-07-05 General Motors Corporation Reinforcement preform, method of making same and reinforced composite material made therefrom
EP1403232A2 (en) * 2002-09-27 2004-03-31 Brilex Gesellschaft für Explosionsschutz mbH Flame-arresting solid material
US8158053B2 (en) * 2000-08-31 2012-04-17 Foseco International Limited Refractory articles

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6237683A (en) * 1985-08-09 1987-02-18 東芝セラミツクス株式会社 Tool for baking ceramic
DE3936230A1 (en) * 1989-10-31 1991-05-02 Wacker Chemie Gmbh UNDER THE IMPACT OF WATER STABLE SHEARS BASED ON ALUMINUM OXIDE, KOERPER CREATED THEM AND MIXTURES FOR THEIR PREPARATION
DE19805889C2 (en) * 1998-02-13 2001-07-12 Fraunhofer Ges Forschung Sintered body based on corundum with a closed cell structure, its production and use
DE10251548A1 (en) * 2002-11-05 2004-05-19 Cramer Sr, S.R.O. Performance-optimized radiation burner

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH622230A5 (en) * 1975-03-28 1981-03-31 Alusuisse Porous ceramic foam, process for its manufacture and its use

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0466215A2 (en) * 1986-03-19 1992-01-15 Ceramiques Et Composites Filter for liquid metals, based on alveolar ceramic material, process for the production thereof, and its use in filtering liquid metals or alloys having high melting points
EP0466215A3 (en) * 1986-03-19 1992-03-11 Ceramiques Et Composites Filter for liquid metals, based on alveolar ceramic material, process for the production thereof, and its use in filtering liquid metals or alloys having high melting points
US5110470A (en) * 1989-10-26 1992-05-05 Toto Ltd. Ceramic filter and process for making it
US5045511A (en) * 1990-02-26 1991-09-03 Alusuisse-Lonza Services, Ltd. Ceramic bodies formed from yttria stabilized zirconia-alumina
EP0471910A1 (en) * 1990-08-20 1992-02-26 Toto Ltd. Process for making a ceramic filter
US5098571A (en) * 1990-08-20 1992-03-24 Toto Ltd. Ceramic filter and process for making it
GB2260538A (en) * 1991-10-15 1993-04-21 Peter Gant Porous ceramics
GB2260538B (en) * 1991-10-15 1995-08-16 Peter Gant Ceramic block for liquid retention
EP0661247A1 (en) * 1993-12-20 1995-07-05 General Motors Corporation Reinforcement preform, method of making same and reinforced composite material made therefrom
US8158053B2 (en) * 2000-08-31 2012-04-17 Foseco International Limited Refractory articles
EP1403232A2 (en) * 2002-09-27 2004-03-31 Brilex Gesellschaft für Explosionsschutz mbH Flame-arresting solid material
EP1403232A3 (en) * 2002-09-27 2008-07-30 Brilex Gesellschaft für Explosionsschutz mbH Flame-arresting solid material

Also Published As

Publication number Publication date
GB8527211D0 (en) 1985-12-11
DE3540450A1 (en) 1986-06-12
GB2168336B (en) 1988-02-10
DE3540450C2 (en) 1989-06-29

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19941105