| NMC | V-1 | Clear |
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| NMS | V-2 |
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Large transmitter capacitors, bolometers, metalized resistance cards, special high quality TV applications, air regulating diaphragms | ||
| NMF | V-3 |
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Low power loss and high “Q” – for radio & general electronic | ||
| NMG | V-4 |
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“Q” slightly lower – for average radio & electronic works Mica Observation Window for Gauge Glass and Oil Burner | ||
| NMSA | V-5 |
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Small capacitors and high quality radio tube spacers | ||
| NMSB | V-6 |
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Absolutely clear fuse windows for special applications | ||
| NMH | V-7 |
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Fuse windows, heating elements, neon electrodes, thermostat insulators, low quality tube spacers & for low voltage applications | ||
| NMBS | V-10 |
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Resistors, motors & appliances (more surface leakage & stains conduct at high voltage) | ||
| NMBD | V-8 |
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110 / 220 volt insulation, transformer layer insulation, appliances | ||
| NMBS | V-9 |
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Non-conductive dots & spots (small surface leakage in mica) | ||
FEDERAL & ASTM Specifications
Federal and ASTM specifications may be used at any time, as we are able to furnish certificates of compliance on the products fabricated.
Following are some of the applicable specifications:
| ASTM-D-351-97 : | VISUAL QUALITY MICA |
| ASTM-D-748 : | MICA FOR FIXED CAPACITORS |
| HH-I-536 : | VISUAL QUALITY MICA |
| HH-I-538 : | ELECTRICAL PASTED MICA |
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 | 00-500°C |
| Specific heat (25°C) | .206-.209 |
| Thermal Conductivity perpendicular to cleavage | Cal./Sq. Cm./Sec./Cm./°C : 16×10-4 B.T.U./Sq. Ft./Hr./I.°F : 4.6 |
| Coefficient of expansion per °C perpendicular to cleavage | 20° – 100° C : 15×10-6 – 25×10-6 100° – 300° C : 15×10-6 – 25×10-6 300° – 600° C : 16×10-6 – 36×10-6 |
| Coefficient of expansion per °C parallel to cleavage | 0° – 200° C : 8×10-6 – 9×10-6 200° – 500° C : 10×10-6 – 12×10-6 |
| Tensile strength P.S.I. | 37,000 – 43,000 |
| Modulus of elasticity | 25×106 |