Qualities & Properties of Muscovite Mica
| FED SPEC HHI 536 | ASTM D-351 | COMMERCIAL CLASS | USES | SCALE OF COMPARATIVE VALUE |
|---|---|---|---|---|
QUALITY: SUPERFINE |
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| NMC | V-1 | Clear | Geiger-Muller counter windows, Klystron Tubes, Microwave windows, X-Ray Analysis Instrument, Ultra-thin Mica Windows, Medical, Nuclear, Airborne. | 100 |
| NMS | V-2 | Clear & Slightly Stained | Large transmitter capacitors, bolometers, metalized resistance cards, special high quality TV applications, air regulating diaphragms | 65 |
QUALITY: CAPACITOR QUALITY |
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| NMF | V-3 | Fair Stained | Low power loss and high "Q" - for radio & general electronic | 45 |
| NMG | V-4 | Good Stained | "Q" slightly lower - for average radio & electronic works Mica Observation Window for Gauge Glass and Oil Burner |
32 |
QUALITY: RADIO TUBE QUALITY |
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| NMSA | V-5 | Stained A | Small capacitors and high quality radio tube spacers | 14 |
| NMSB | V-6 | Stained B | Absolutely clear fuse windows for special applications | 12 |
QUALITY: CLEAR ELECTRIC |
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| NMH | V-7 | Heavy Stained | Fuse windows, heating elements, neon electrodes, thermostat insulators, low quality tube spacers & for low voltage applications | 10 |
QUALITY: SPOTTED ELECTRIC, STAINED ELECTRIC |
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| NMBS | V-10 | Black Stained | Resistors, motors & appliances (more surface leakage & stains conduct at high voltage) | 3 |
| NMBD | V-8 | Black Dotted | 110 / 220 volt insulation, transformer layer insulation, appliances | 5 |
| NMBS | V-9 | Black Spotted | Non-conductive dots & spots (small surface leakage in mica) | 4 |
FEDERAL & ASTM Specifications
| Federal and ASTM specifications may be used any time, as we are able to furnish certificate of compliance on the products fabricated. Following are some of the applicable specifications:
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MUSCOVITE MICA: PROPERTIES
Optical |
|
|---|---|
| Optic axial angle (2V) degrees | 38 - 47 |
| Optic plane to plane of symmetry Orientation | Perpendicular |
| Indices of refraction | Alfa : 1.552 - 1.570 Beta : 1.582 - 1.607 Gamma : 1.588 - 1.611 |
Electrical | |
| Dielectric Constant | 6.5 - 9 |
| Dielectric Strength ( 1-3 mils thick), Volts/Mil. | 6,000 - 3,000 |
| Power Factor at 25°C (77°F) (), percent: | 60 cycles : 0.08 - 0.09 1 megacycle : 0.01- 0.02 |
| Resistivity, Ohm-Cm | 1012 - 1015 |
Mechanical | |
| Density | Gr./Cu. Cm. : 2.6-3.2 Lb./Cu. Ft. : 160-200 |
| Hardness, Mohs | 2.0-3.2 |
| Cleavage | Basal, Eminent |
| Crystal Structure | Monoclinic |
| Max. Temperature with no decomposition | 400-500°C |
| Specific heat (25°C) | .206-.209 |
| Thermal Conductivity perpendicular to cleavage | Cal./Sq. Cm./Sec./Cm./°C : 16x10-4 B.T.U./Sq. Ft./Hr./I.°F : 4.6 |
| Coefficient of expansion per °C perpendicular to cleavage | 20° - 100° C : 15x10-6 - 25x10-6 100° - 300° C : 15x10-6 - 25x10-6 300° - 600° C : 16x10-6 - 36x10-6 |
| Coefficient of expansion per °C parallel to cleavage | 0° - 200° C : 8x10-6 - 9x10-6 200° - 500° C : 10x10-6 - 12x10-6 |
| Tensile strength P.S.I. | 37,000 - 43,000 |
| Modulus of elasticity | 25x106 |
