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KMg3(AlSi3O10)(OH)2 - is a hydrous potassium magnesium aluminium silicate. Here the calcination temperature is reached at about 800 C. Generally speaking, Phlogopite Mica is softer than Muscovite Mica and this for instance makes it more suitable for the manufacture of commutator Micanite used in commutators of flush running designs.
Phlogopite Mica is commonly called Amber Mica and varies in color from light silver to dark brown. Phlogopite Mica has poor electrical properties and cheMical resistance in comparsion to Muscovite Mica. |
| Physical Properties |
| |
|
Specific gravity |
2.82 |
|
Index of refraction |
1.58 |
|
Hardness (Moh's scale) |
2.5 |
|
pH value (BS 3483) |
7.7 |
|
pH for distilled water |
5.2 |
|
Oil absorbtion |
60-90 g/oil |
|
(BS 3483) |
100g Mica |
|
Water Soluble |
Not more |
|
(BS 1765) |
than 0.5% |
|
Effect by common acids |
Slight |
|
Phericity Factor |
0.01 |
|
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| Chemical Properties |
| |
|
Silica (SiO2 ) |
45.70% > |
| Alumina (Al2 O3 )
|
33.10
|
| Potassium Oxide (k2O)
|
09.87%
|
| Ferric Oxide (Fe2O3)
|
02.48%
|
| Sodium Oxide (Na2O)
|
00.62%
|
| Titanium Oxide (TiO2)
|
Trace
|
| Calcium Oxide (CaO) |
00.21% |
| Magnesia (MgO)
|
00.38% |
| Moisture @ 100 °C |
00.25% |
| Phosphorous (P) |
00.03% |
| Sulphur (S) |
00.01% |
| Graphitic Carbon (C) |
00.44% |
| Loss on ignition (H2O) |
02.74% |
|
|
Properties
|
Units
|
Muscovite |
Phlogopite
|
|
Color
|
|
Ruby/ Green/ White |
Amber/ Silver/Green |
|
Density |
gm/cm3 |
2.6 - 3.2
|
2.6 - 3.2 |
|
Specific heat |
|
0.21
|
0.20 |
|
Hardness
|
Moh scale |
2.8 - 3.2
|
2.3 - 3.0 |
| |
Shore Test |
80-105 |
70-100 |
|
Breakdown voltage
|
KV/mm |
120 - 200
|
- |
|
Coefficient of expansion per °C perpendicular to cleavage plane
|
|
9 x 10-6 – 36 x 10-6 |
30 x 10-6 – 60 x 10-6 |
|
Thermal conductivity perpendicular to cleavage plane
|
Gm.cal/sec/cm2/°C/cm |
about 0.0013
|
about 0.0010 |
| |
BTU/hr/ft2/0f/ft |
about 0.31 |
about 0.24 |
|
Thermal conductivity parallel to cleavage plane
|
Gm.cal/sec/cm2/°C/cm |
|
about 0.012 |
| |
BTU/hr/ft2/0f/ft |
|
about 3.0 |
|
Water of Constitution %
|
|
4.5 |
3.0 |
|
Moisture Absorption
|
|
Very low |
Very low |
|
Volume Resistivity
|
25°C (77°F) ohm cm |
40 x 1013 -2 x 1017 |
1 x 1012 -1 x 1012 |
|
Acid Reaction
|
|
affected by hydrofluoric acid |
affected by sulphuric acid |
|
Insulation resistence
|
x1013ohm/cm |
4-20000
|
0.1 - 10 |
|
Calcining temp
|
°C |
700-800
|
900-1000 |
|
Max. operating temp
|
°C |
500-600
|
800-1000 |
|
Optic axial angle
|
degrees |
55 - 75
|
5 -25 |
|
Tensile strength
|
MN/m2 |
175
|
1000 |
|
Shear strength
|
MN/m2 |
220 - 270
|
1000-1300 |
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Compression strength
|
MN/m2 |
190 - 285
|
- |
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Modulus of Elasticity
|
Kgfcm2 x 10-3
lbf/in2 x 10-6 |
1400 – 2100
20 - 30 |
1400 – 2100
20 – 30 |
|
Loss tangent
|
x10-4 |
1-4
|
10-50 |
|
Permittivity at 15°C (60°F)
|
|
6 - 7 |
5 -6 |
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