Property

Materials

Alumina
95％

Alumina
92％

Alumina
90％

Mullite

Porcelain

Steatite

Zircon cordierite

Formula, composition

Al₂O₃

Al₂O₃

Al₂O₃

-

-

MgO・SiO₂

Zircon cordierite

Alumina content

%

95

92

90

50～60

-

-

-

Apparent density (specific gravity)

kg/cm³

3.7

3.6

3.6

2.6

2.5

2.7

2.8

Water absorption

%

0

0

0

0

-

0

0

Mechanical property

Bending strength

N/mm²

275

280

270

170

69

180

140

Compressive strength

N/mm²

-

2150

2000

1470

411

-

580

Thermal property

Thermal properties

RT～200°c

×10^-6／k

-

-

-

5.6

-

-

-

RT～400°c

-

7.2

7.4

-

-

-

-

RT～500°c

7.7

-

7.6

-

-

8

-

RT～700°c

-

7.4

7.8

-

5

-

2.8

RT～800°c

-

-

-

-

-

-

-

Thermal conductivity　20°c

W/(m・K)

16.7

16.7

16.7

3.5

1.16

2

2.9

Electrical characteristics

Dielectric strength

kV/mm

>15

>13

12

10

<10

11

-

Volume resistivity

20°c

Ω･cm

>10¹⁴

>10¹⁴

>10¹⁴

-

10¹²

>10¹⁴

10¹²

100°c

>10¹³

-

>10¹³

10¹²

10¹⁰

-

-

200°c

>10¹²

>10¹²

>10¹²

10⁹

10⁷

10¹²

10⁹

300°c

>10¹⁰

-

>10¹⁰

10⁸

10⁶

10¹⁰

-

400°c

-

-

-

10⁷

10⁵

10⁹

-

Permittivity （1MHz）

－

9.3

9

8.5

-

5.5

7

5

Key features

Injection
molding
complex-shaped

Powder molding press
simple geometry
effective mass production

extrusion
slip casting
lengthwise possible

Variety injection molded
extrusion
powder molding press
(dry and wet)

Low thermal conductivity
large insulated

Low thermal expansion