beryllium oxide ceramic beryllium oxide insulators have a high dielectric strength, which allows safe operating voltages of 1500 volts or more. for applications involv ing 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 wm - 1 c - 1 (128.2 btu/hr.ft.f). beryllium oxide is chemically inert an d 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, grindin gs, 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 25c test method chemical be0 content 99.5% minimum spectograph analysis (100% - % by wt. of total metallic impurity). electrical dielectric constant 25c (77f) 6.5 (1mhz) 6.6 (10ghz) astm d150 - 70 astm d2520 - 70 dissipation factor 25c (77f) .0004 (1mhz) .0004 (10ghz) astm d150 astm d2520 electrical resistivity 25c (77f) >10 15 ohm - cm astm d150 astm d257 - 61 dielectric strength (ac) 22.8 x 10 3 volts/mm ( .81mm) [580 volts/mil (0.32")] astm d149 - 84 physical density 2.85 g/cm 3 (min) 177.93 lb/ft 3 astm c373 - 66 astm f77 - 671 hardness 60 minimum (rockwel 45n) astm e18 - 67 mechanical flexural strength 25c (77f) 2.27 x 10 8 pa (min.) (33,000 psi min.) astm mic robar 8025 astm d2442 - 70a3 modules of elasticity 3.45 x 10 11 pa (50 x 10 6 psi) astm d2442 - 70a4 poisson's ratio 0.26 astm d2442 - 70a4 tensile strength 25c (77f) 1.52 x 10 8 pa (22,000 psi ) astm 565 - 66t compressive strength 25c (77f) 1.55 x 10 9 pa (25,00 0 psi) astm c528 thermal coefficient of thermal expansion 9.0 x 10 - 6 /c 5.0 x 10 - 6 /f astm e - 228 astm c372 - 56 astm c327 - 56 astm c408 - 82 thermal conductivity 251.28 wm - 1 c - 1 (25f) [145.14 btu/hr.ft f] (77f) 186.44 wm - 1 c - 1 (100f) [106.86 btu/hr.ft f ] (212f) astm c408 - 82
146.57 wm - 1 c - 1 (150f) [84.67 btu/hr.ft f] (302f) specific heat (180c) 1.0 x 10 - 3 kj/kgc [2.5 x 10 - 4 btu/lb f] astm c351 - 81 melting point 2552c (4625f) maximum temperature for continuous use 2149c (3900f)
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