Zircar Ceramics: ALC & ALC-AA

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102.jpg (3709 bytes) Alumina Insulation Type ALC & ALC-AA

GENERAL INFORMATION
ZIRCAR Alumina Insulation Type ALC and ALC-AA are strong, rigid refractory structures of alumina fiber and high purity inorganic binders. They possess very low thermal conductivity, good hot strength and dimensional stability. Optimum fiber density of 0.24 gm/cc (15 lb/ft³) is maintained to provide highly efficient thermal insulation to continuous for use at temperatures of 1550°C (2882°F), with intermittent use to 1650°C (3002°F).

High purity silica is the binder in ALC. At temperatures above 1100°C (2010°F), ceramic bonds the silica binder reacts with the fibers are formed to create an even stronger mullite bond this imparts greater high temperature strength and dimensional stability. ALC-AA has a high purity alumina bond, for high vacuum, reducing atmospheres and other applications where silica cannot be tolerated.

These materials show excellent resistance to chemical attack and are not affected by oil or water. They are, however, affected by hydrofluoric acid, phosphoric acid and strong alkalis. ALC and ALC-AA insulating cylinders are prefired and contain no organic binders and produce no smoke or odor when heated.

See ZIRCAR Alumina Insulation Type ZAL-15 and ZAL-15AA for boards.

CHARACTERISTICS & PROPERTIES

TYPE	ALC	ALC-AA
Nominal Composition, wt.%
Al₂O₃	85	97
SiO₂	15	3
Organic Content	0	0
Bond	Silica	Alumina
Density, g/cc (pcf)	0.24 (15)
Maximum Use Temperature*,°C (°F)
Continuous	1550 (2882)	1500 (2732)
Intermittent	1650 (3002)	1550 (2822)
Melting Point, °C (°F)	1870 (3992)
Color	White
Open Porosity, %	93
Specific Heat, BTU/lb°F (J/kg°K)	0.25 (1024)
Linear Shrinkage‡,
1 hr. at 1550°C (2822°F)	1	2
1 hr. at 1650°C (3002°F)	3	6
Thermal Conductivity**, (ASTM C177-76) W/m°K (BTU/hr ft² °F/in)
400°C (752°F)	0.07 (0.5)
800°C (1472°F)	0.13 (0.9)
1100°C (2012°F)	0.19 (1.3)
1400°C (2552°F)	0.26 (1.8)
1650°C (3002°F)	0.28 (1.9)
Thermal Expansion Coefficient, Room temp. to 1000°C (1832°F)	5.0x10^-6/°C (2.8x10^-6/°F)	7.5x10^-6/°C (4.2x10^-6/°F)
Compressive Strength

Flexural Strength

*	Maximum use temperature is dependent on variables such as stresses, both thermal and mechanical, and the chemical environment that the material experiences.
**	Properties expressed parallel to thickness.
‡	Properties expressed perpendicular to thickness.

Load Orientation
1	2	3	4
Load Applied Normal To Fiber Plane	Load Applied Parallel To Fiber Plane	Load Applied Normal To Fiber Plane	Load Applied Parallel To Fiber Plane

MATERIAL SAFETY DATA SHEET

SUGGESTED APPLICATIONS

ALC

Primary thermal insulation in low mass furnaces and thermal process systems operating to 1650°C (3002°F).

Backup thermal insulation in furnaces and thermal process systems operating to temperatures exceeding 2000°C (3632°F).

Launders, distribution boxes, pouring spouts, hot tops and others involving molten metal contact.

High temperature setters, supports and process fixtures.

Electrical insulation in high temperature systems operating to 1650°C (3002°F).

ALC-AA

Primary thermal insulation in bright annealing furnaces and other thermal process systems with hydrogen gas atmospheres operating to 1550°C (2822°F).

Thermal insulation, supports and fixtures Solid Oxide Fuel Cells operating to 1550°C (2822°F).

Backup thermal insulation in furnaces and thermal process systems operating to temperatures exceeding 2000°C (3632°F).

Launders, distribution boxes, pouring spouts, hot tops and others involving molten metal contact.

High temperature setters, supports and process fixtures for use in reducing atmospheres.

Electrical insulation in high temperature systems operating to 1550°C (2822°F).

AVAILABILITY

Nested cylinders are available on request.

Cylinders typically produced have 1" to 12"ID, ½" to 2" wall thickness and are up to 20" long. Custom cylinders and shapes smaller than a few cubic inches, larger than several cubic feet, weighing up to 50 pounds, with ID’s of ¼" to 24", wall thickness of 1/8"’ to 3" and lengths to 48" have been manufactured.

Custom cylinders, shapes and preparations are available on request. Our forming processes, large inventory of custom tooling and state of the art machining techniques allow a wide variety of sizes and shapes to be made. Special geometries such as custom bore (round corner square, hexagonal, oval, etc.) cylinders, staved cylinders troughs, channel, angle, custom machined shapes and others can be fabricated. Tight tolerance machining, compositional variations and the application of surface rigidizers and hardening agents are available.

Please contact us with your special requirements. We are pleased to contact you if you would like more information or want to discuss custom product availability and pricing.

To Order

Custom cylinders: specify quantity, product type and size. Example: 24ea, ALC-AA, 3"ID x 4.65"OD x 15.3"L

Custom cylinders, shapes and preparations: specify quantity, product type and description (by supplying drawings, sketches, written descriptions or material specifications).