Alumina – Aluminum Oxide

Modern alumina (Al₂O₃) products are among the strongest and hardest of all ceramic materials. They also have a high dielectric strength and at elevated temperatures, such as those encountered in many applications, their electrical resistance is excellent. Alumina ceramics also feature very high mechanical strength, high thermal conductivity, and high resistance to chemical and corrosion attack at room and elevated temperatures. Further, this valuable class of materials can be made extremely hard - second only to diamond on the Mohs' scale, for resistance to wear and abrasion. Many of alumina's outstanding properties can be enhanced through variation in manufacturing methods and in chemistry. Associated Ceramics has earned a reputation for achieving dimensionally accurate alumina parts with excellent quality and reproducibility. Shapes shown are not to scale.

Alumina Properties	Units	ACT 800-850	ACT 900,920,960	ACT 990,997,999	ACTMA 99
Alumina Content		80-85%	90-96%	> 99.5%	99%
General Application		Lower Cost Electrical & Mechanical	High Strength, Wear Resistant, Electronic, Insulating, Mechanical, Structural & Metalizing	Extremely High Purity, Temperature & Strength; Excellent Corrosion & Wear Resistance	Porous, Easily Degassed & Machinable
Color (Fired)		White	White	Off White	White
Porosity	%	0-.05	0-.05	0-.05	Variable
Density	gm/cm3	3.45-3.50	3.55-3.75	3.75-3.95	2.4
Flexural Strength	kpsi	35.0-40.0	40.0-50.0	50.0-55.0	-
Comprehensive Strength	kpsi	260.0	> 300.0	> 300.0	-
Tensile Strength	kpsi	15.0-20.0	20.0-28.0	20.0-28.0	-
Linear Coefficient of Thermal Expansion	(cm/cm/°C) 25-300°C 25-700°C	5.9X10-6 6.5X10-6	6.3X10-6 7.0X10-6	6.5X10-6 7.5X10-6	6.5X10-6 7.5X10-6
Dielecctric Constant at 25°C	1 MH 10 MH	8.5-8.9 8.4-8.8	9.2-9.8 9.0-9.6	9.5-9.9 9.3-9.7	-
Dielectric Strength	Volt/mil	200	225	225	-
Te Value	°F °C	1472 800	> 1832 > 1000	> 1832 > 1000	> 1832 > 1000
Thermal Conductivity at 25°C	cal/sec/cm2/cm/°C	.03-.04	.04-.06	.07-.08	-
Thermal Shock		Good	Good	Good	Good
Safe Use Temperature	°F °C	2550 1400	3000-3100 1650-1700	3275 1800	3275 1800

Above values are test specimen results and actual shapes may vary in value.
We can work with other formulations as well.