PROPERTY UNIT ALUMINA CERAMICS
  Typical Application   Tubes for pyrometers and all gas thermo elements. Resistant to thermal stresses. Tubes for pyrometers and all gas thermo elements. Electrical and thermal insulators, tube linings and other engineering elements Mettalized ceramics metal/ceramic assemblies in vacuum electrical technique Ceramics resistant to acid and alkali attacks in chemical industry Elements of pumps and fittings, paper industry, laboratory accessories, etc. Tubes
Type to DIN 40685   C 530 C 610 C 795 C 795 C 795 C 799 C 799
Al2O3 Content % 78 62 95 97 98,5 99,7 99,7
Specific Gravity g/cm³ 2,5 2,7 3,68 3,76 3,8 3,88 3,82
Water Absorption % 8 - 12 0 0 0 0 0 0
Hardness Mohs 6 8 9 9 9 9 9
Modulus of Elasticity GPa   100 280 280 280 300 300
Flexural Strength N/mm² 30 120 280 280 280 300 300
Coefficient of
Linear Expansion
(20–100) °C
(20–300)°C
(20–600) °C
(20–1000) °C		 10-6/K 3,5 – 5
3,5 – 5
4 – 6
4 - 7 		5 – 6
5 – 6
5 – 7
5 - 7 		5 - 7
6 – 7,5
6 - 8
7 - 9 		5 - 7
6 – 7,5
6 - 8
7 - 9 		5 - 7
6 – 7,5
6 - 8
7 - 9 		5 – 7
6 – 8
7 – 8
7 - 9 		5 – 7
6 – 8
7 – 8
7 - 9
Specific Heat (20 – 100 ) °C J/KgK 800 - 900 850 - 1050 850 - 1050 850 - 1050 850 - 1050 850 - 1050 850 - 1050
Thermal Conductivity L (20 – 100 ) °C W/(mK) 1.4 - 2 4 - 6 16 - 28 16 - 28 16 - 28 19 - 30 19 - 30
Maximum Thermal Stress (D t) K 350 150 140 140 140 150 150
Dielectric Constant (48 Hz – 62 Hz)     8 9 9 9 9 9
Dielectric Strength [KV/mm]   17 15 15 15 17 17
Max. Operating Temperature K 1873 1873 1773 1773 1873 1923 1923
               

back