Qualities & Properties of Muscovite Mica

FED SPEC HHI 536

ASTM D-351

COMMERCIAL CLASS

USES

SCALE OF
COMPARATIVE VALUE

QUALITY: SUPERFINE

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

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

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

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

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:

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

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


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