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Materials

 

Accuflect®

Aluminum Nitride

Aluminum Oxide

Boron Nitride

Fused Silica

Macor®

Mullite

Sialon

Silicon Carbide

Silicon Nitride

Zirconium Oxide

 

 

Aluminum Oxide, Al2O3 Ceramic Properties

Alumina is one of the most cost effective and widely used material in the family of engineering ceramics. The raw materials from which this high performance technical grade ceramic is made are readily available and reasonably priced, resulting in good value for the cost in fabricated alumina shapes. With an excellent combination of properties and an attractive price, it is no surprise that fine grain technical grade alumina has a very wide range of applications.

.Key Properties

check Hard, wear-resistant
check Excellent dielectric properties from DC to GHz frequencies
check Resists strong acid and alkali attack at elevated temperatures
check Good thermal conductivity
check Excellent size and shape capability
check High strength and stiffness
check Available in purity ranges from 94%, an easily metallizable composition, to 99.8% for the most demanding high temperature applications.
.

Typical Uses

check Gas laser tubes
check Wear pads
check Seal rings
check High temperature electrical insulators
check High voltage insulators
check Furnace liner tubes
check Thread and wire guides
check Electronic substrates
check Ballistic armor
check Abrasion resistant tube and elbow liners
check Thermometry sensors
check Laboratory instrument tubes and sample holders
check Instrumentation parts for thermal property test machines
check Grinding media

General Information

Aluminum oxide, commonly referred to as alumina, possesses strong ionic interatomic bonding giving rise to it’s desirable material characteristics. It can exist in several crystalline phases which all revert to the most stable hexagonal alpha phase at elevated temperatures. This is the phase of particular interest for structural applications and the material available from Accuratus.

Alpha phase alumina is the strongest and stiffest of the oxide ceramics. Its high hardness, excellent dielectric properties, refractoriness and good thermal properties make it the material of choice for a wide range of applications.

High purity alumina is usable in both oxidizing and reducing atmospheres to 1925°C. Weight loss in vacuum ranges from 10–7 to 10–6 g/cm2.sec over a temperature range of 1700° to 2000°C. It resists attack by all gases except wet fluorine and is resistant to all common reagents except hydrofluoric acid and phosphoric acid. Elevated temperature attack occurs in the presence of alkali metal vapors particularly at lower purity levels.

The composition of the ceramic body can be changed to enhance particular desirable material characteristics. An example would be additions of chrome oxide or manganese oxide to improve hardness and change color. Other additions can be made to improve the ease and consistency of metal films fired to the ceramic for subsequent brazed and soldered assembly.

 

Engineering Properties*

94% Aluminum Oxide

Mechanical

Units of Measure

SI/Metric

(Imperial)

Density

gm/cc (lb/ft3)

3.69

(230.4)

Porosity

% (%)

0

(0)

Color

white

Flexural Strength

MPa (lb/in2x103)

330

(47)

Elastic Modulus

GPa (lb/in2x106)

300

(43.5)

Shear Modulus

GPa (lb/in2x106)

124

(18)

Bulk Modulus

GPa (lb/in2x106)

165

(24)

Poisson’s Ratio

0.21

(0.21)

Compressive Strength

MPa (lb/in2x103)

2100

(304.5)

Hardness

Kg/mm2

1175

Fracture Toughness KIC

MPa•m1/2

3.5

Maximum Use Temperature
(no load)

°C (°F)

1700

(3090)

Thermal




Thermal Conductivity

W/m•°K (BTU•in/ft2•hr•°F)

18

(125)

Coefficient of Thermal Expansion

10–6/°C (10–6/°F)

8.1

(4.5)

Specific Heat

J/Kg•°K (Btu/lb•°F)

880

(0.21)

Electrical




Dielectric Strength

ac-kv/mm (volts/mil)

16.7

(418)

Dielectric Constant

@ 1 MHz

9.1

(9.1)

Dissipation Factor

@ 1 kHz

0.0007

(0.0007)

Loss Tangent

@ 1 kHz

Volume Resistivity

ohm•cm

>1014

 

96% Aluminum Oxide

Mechanical

Units of Measure

SI/Metric

(Imperial)

Density

gm/cc (lb/ft3)

3.72

(232.2)

Porosity

% (%)

0

(0)

Color

white

Flexural Strength

MPa (lb/in2x103)

345

(50)

Elastic Modulus

GPa (lb/in2x106)

300

(43.5)

Shear Modulus

GPa (lb/in2x106)

124

(18)

Bulk Modulus

GPa (lb/in2x106)

172

(25)

Poisson’s Ratio

0.21

(0.21)

Compressive Strength

MPa (lb/in2x103)

2100

(304.5)

Hardness

Kg/mm2

1100

Fracture Toughness KIC

MPa•m1/2

3.5

Maximum Use Temperature
(no load)

°C (°F)

1700

(3090)

Thermal




Thermal Conductivity

W/m•°K (BTU•in/ft2•hr•°F)

25

(174)

Coefficient of Thermal Expansion

10–6/°C (10–6/°F)

8.2

(4.6)

Specific Heat

J/Kg•°K (Btu/lb•°F)

880

(0.21)

Electrical




Dielectric Strength

ac-kv/mm (volts/mil)

14.6

(365)

Dielectric Constant

@ 1 MHz

9.0

(9.0)

Dissipation Factor

@ 1 kHz

0.0011

(0.0011)

Loss Tangent

@ 1 kHz

Volume Resistivity

ohm•cm

>1014

 

99.5% Aluminum Oxide

Mechanical

Units of Measure

SI/Metric

(Imperial)

Density

gm/cc (lb/ft3)

3.89

(242.8)

Porosity

% (%)

0

(0)

Color

ivory

Flexural Strength

MPa (lb/in2x103)

379

(55)

Elastic Modulus

GPa (lb/in2x106)

375

(54.4)

Shear Modulus

GPa (lb/in2x106)

152

(22)

Bulk Modulus

GPa (lb/in2x106)

228

(33)

Poisson’s Ratio

0.22

(0.22)

Compressive Strength

MPa (lb/in2x103)

2600

(377)

Hardness

Kg/mm2

1440

Fracture Toughness KIC

MPa•m1/2

4

Maximum Use Temperature
(no load)

°C (°F)

1750

(3180)

Thermal




Thermal Conductivity

W/m°K (BTU•in/ft2•hr•°F)

35

(243)

Coefficient of Thermal Expansion

10–6/°C (10–6/°F)

8.4

(4.7)

Specific Heat

J/Kg•°K (Btu/lb•°F)

880

(0.21)

Electrical




Dielectric Strength

ac-kv/mm (volts/mil)

16.9

(420)

Dielectric Constant

@ 1 MHz

9.8

(9.8)

Dissipation Factor

@ 1 kHz

0.0002

(0.0002)

Loss Tangent

@ 1 kHz

Volume Resistivity

ohm•cm

>1014

*All properties are room temperature values except as noted.
The data presented is typical of commercially available material and is offered for comparative purposes only. The information is not to be interpreted as absolute material properties nor does it constitute a representation or warranty for which we assume legal liability. User shall determine suitability of the material for the intended use and assumes all risk and liability whatsoever in connection therewith.

See also: Ceramic Rod & Tube
See also: Ceramic Rod & Tube > Available Aluminum Oxide Sizes

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