ASTMD257-61 [ETC]

Beryllium Oxide Ceramic;


型号：	ASTMD257-61
厂家：	ETC
描述：	Beryllium Oxide Ceramic
文件：	总3页 (文件大小：24K)
中文：	中文翻译
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Beryllium Oxide Ceramic

Beryllium oxide insulators have a high dielectric strength, which allows safe

operating voltages of 1500 volts or more. For applications involving high frequency

or high pulse rate circuitry, the inherent low electrical capacitance of these insulators

revents circuit detuning and loss of signal power. Beryllium oxide insulators have a

dielectric strength of approximately 22.8 x 103 volts/mm for .81mm material (580

volts/mil for .032" material), and 17.7 x 103 volts/mm for 1.57mm material (450

volts/mil for .062 material). The thermal conductivity of beryllium oxide is 221.94

-1

Wm °C^-1(128.2 Btu/hr.ft.°F).

Beryllium oxide is chemically inert and completely safe to use in its fired state.

Handling of finished parts presents absolutely no health hazards. Beryllium oxide,

however, is toxic when dust, mist or fumes containing particles small enough to

enter the lungs are inhaled. Therefore, grindings, sanding, and pulverizing the

material should be avoided.

For TO-3

"A" = 39.65 (1.561)

"B" = 26.67 (1.050)

"C" = 3.68 (.145)

"D" = 3.68 (.145)

Part No. 4003, Thickness .062 (1.57)

Beryllium Oxide

PROPERTY

TYPICAL VALUE 25°C

CHEMICAL

TEST METHOD

Spectograph Analysis

(100%-% by wt. of total

metallic impurity).

Be0content

99.5% minimum

ELECTRICAL

Dielectric Constant

25°C (77°F)

6.5 (1MHz)

6.6 (10GHz)

ASTM D150-70

ASTM D2520-70

Dissipation Factor

25°C (77°F)

.0004 (1MHz)

.0004 (10GHz)

ASTM D150

ASTM D2520

Electrical Resistivity

25°C (77°F)

ASTM D150

ASTM D257-61

>10¹⁵ohm-cm

22.8 x 10³volts/mm

(.81mm) [580 volts/mil

(0.32")]

Dielectric Strength

(AC)

ASTM D149-84

PHYSICAL

2.85 g/cm (min)

ASTM C373-66

ASTM F77-671

Density

177.93 Lb/ft³

60 minimum

(Rockwel 45N)

Hardness

ASTM E18-67

MECHANICAL

Flexural Strength

25°C (77°F)

2.27 x 10⁸Pa (min.)

(33,000 psi min.)

ASTM Microbar 8025

ASTM D2442-70A3

3.45 x 10¹¹Pa (50 x

Modules of Elasticity

ASTM D2442-70A4

ASTM 565-66T

10⁶psi)

Poisson's Ratio

0.26

Tensile Strength 25°C 1.52 x 10⁸Pa (22,000 psi

(77°F)

)

Compressive Strength 1.55 x 10⁹Pa (25,000

ASTM C528

25°C (77°F)

psi)

THERMAL

ASTM E-228

ASTM C372-56

ASTM C327-56

ASTM C408-82

Coefficient of Thermal

Expansion

9.0 x 10^-6/°C

5.0 x 10^-6/°F

-1

251.28 Wm °C^-1(25°F)

[145.14 Btu/hr.ft °F]

(77°F)

Thermal Conductivity

ASTM C408-82

-1

186.44 Wm °C^-1(100°F)

[106.86 Btu/hr.ft °F]

(212°F)

-1

146.57 Wm °C^-1(150°F)

[84.67 Btu/hr.ft °F]

(302°F)

1.0 x 10^-3KJ/Kg°C

Specific Heat (180°C)

Melting Point

ASTM C351-81

[2.5 x 10^-4Btu/Lb °F]

2552°C (4625°F)

Maximum

Temperature for

2149°C (3900°F)

Continuous Use