NO.

Property

Unit

Alumina

1

Al₂O₃

%

>99.3

2

SiO₂

%

-

3

Density

g/cm³

3.88

4

Water absorption

%

0.01

5

Cold compressive strength

MPa

350

6

20ºC leakage rates

Torr/L.sec

<10^-11

7

Twisting in high temperature

mm

0.2 allowed in 1600ºC

8

Bonding in high temperature

not bonded in 1600ºC

9

20-1000ºC coefficient ofthermalexpansion

mm.10^-6/ºC.m

8.2

10

Thermal conductivity

W/m.k

25

11

Electric insulation strength

KV/mm

20

12

20ºCdirect current

insulation resistance

Ohm/cm

10¹⁴

13

High-temperature

insulation resistance

1000ºC MΩ

≥0.08

1300ºC MΩ

≥0.02

14

Thermal shock resistance

4 times not cracked in 1550ºC

15

Maximum working temperature

ºC

1800