Muscovite Mica Grades

Created by Kathleen Patrick, Modified on Thu, 13 Jun 2024 at 08:49 AM by Kathleen Patrick

EMS Mica Sheets offer a clean surface for EM applications, carbon filming and particle spraying, as well as for AFM applications. There are two types of mica: muscovite and phlogopite. Generally, one differs from the other by colour (Muscovite is Ruby, Green or White; Phlogopite is Amber, Yellow, or Silver). The maximum operating temperature for Muscovite is about 500-600°C and for Phlogopite is about 800-900°C. Our line consists of High Quality Muscovite Mica. This mica peels off very thin up to 0.0001" uniform layers, exposing "virgin" mica upon splitting.


The highest quality distinction of the mica:

High quality (V-1 or V-2) to the Medium Quality (V-4 to V-6)


The quality of muscovite mica is verbal determination by visual quality classification ASTM (D351-57T) from the best V-1 to the worst is V-10A.


1. V-1: Clear - Hard, of uniform colour, nearly flat, free of all stains, foreign inclusion, cracks, and other similar defects.


2. V-2: Clear and Slightly Stained - Hard, of uniform colour, nearly flat and may contain slight crystallographic discolouration, and very slight air inclusions and not more than one fourth of the usable area.


3. V-3: Fair Stained - Hard, of uniform colour, may contain slight waves, slight crystallographic discolouration, and slight air inclusions and not more than one-half of the usable area.


4. V-4: Good Stained - Hard, of uniform colour, may contain medium waves slight crystallographic discolouration, and medium air inclusion in not more than two-third of the usable area.


5. V-5: Stained A Quality - Hard, may contain medium air inclusions, uniformly distributed in the usable area; slight green vegetable stains, medium waviness, and heavy waves if specified.


6. V-6: Stained B Quality - Hard, may contain heavy air inclusions and heavy waves, medium green vegetable stains, slight black and red dots (mineral) and clay stains.


7. V-7: Heavy Stained - Hard, and may contain heavy air inclusions and waves, slight light black and red dots (mineral), medium cloudy stains, clay stains and green stains (vegetable). Soft, buckles, ridges, and sand blast acceptable if specified.


8. V-7A: Densely Stained - Hard and soft. May contain heavy waves and air inclusions, cloudy stains. High black and red dots (mineral). Medium black and red stained (mineral), buckles, and ridges. Also, green stain (vegetable type), clay stains, herring bones, and sand blast.


9. V-8: Black Dotted - Hard, may contain medium waves, heavy air inclusions, cloudy stains, light black and red dots (mineral), and green stains (vegetable).


10. V-9: Black Spotted - Hard, may contain medium waves, heavy air inclusions, cloudy stains, light black and red dots (mineral), and green stains (vegetable type), slight black stains (mineral), and sand blast.


11. V-10: Black Stained - Hard, may contain medium waves, heavy air inclusions, cloudy stains, light black and red dots (mineral), green stains (vegetable type), and sand blast, medium black stains (mineral), slight red stains (mineral), and clay stains.


12. V-10A: Densely Black and Red Stained - Hard, may contain heavy waves, air inclusion, cloudy stains, light black and red dots (mineral), red stains (mineral), black and red stains (mineral), green stains (vegetable type), and sand blast, very dense black and red stains (mineral), and slight clay stains. Soft if specified.


Characteristics:

Muscovite, potash type mica, also called granitic mica, is indeed the greatest of all micas in dielectric power, cleavage perfection and clarity.

It has the following chemical formula: H2KAI3(Si04)3.


Chemical Composition:

Silica:45.5%
Alumina:37.5%
Potash:12.0%
Water:5.00%


It has a vitreous lustre and is colourless to grey, brown, pale green, violet, dark olive green, or rose red. It may be transparent to translucent. It has strong double refraction and is optically negative. It loses water of constitution at 600°C and is practically non-magnetic. It exhibits pleochrism, which is the property of varying in colour when viewed from different angles.

RUBY muscovite is harder than green and has a pale brownish red colour in thin sheets (0.020") or ruby red in thick plates (0.4"). Ruby mica can be split easily into films of 0.001" or thinner because it has such excellent cleavage. In other colours, this thinness can be obtained but at a considerable risk of cracking.


Physical Properties:

Hardness: Moh's scale:2.8 - 3.2
Shore's Test:80 - 150
Specific Gravity:2.6 - 3.2g/cm3
Tensile Strength:~ 1750kg/cm2
Compression Strength:1900 - 2850kg/cm2
Refractive Index (air=1):1.56 - 1.60/61
Dielectric Strength @20°C in volt/mil:3,000 - 6,000
Maximum Thermal Resistance:625°C (1,157°F)
Modulus of Elasticity, :1400 - 2100kgf/cm2E(-3)
Optic Axial Angle:50° - 75°
Coefficient of Expansion per °C:Perpendicular to cleavage plane 9E(-4) - 36E(-4)
Calcining Temperature700 - 800°C
Thermal Conductivity:~0.0013gm.cal/sec/cm2/°C/cm
Water of Constitution:4 - 5%
Moisture Absorption:Very low
Apparent Electric Strength:
(0.001-0.003" thick)
120 - 200kV/mm
Permittivity @ 15°C:6 - 7
Power Factor (loss Tangent) @15°C:0.0001 - 0.0004
Volume Resistively @25°C:4E(-15) - 2E(-17)Ohm.cm
Acid Reaction:Affected by HF


Applications:

In general, for those whom are using mica for the making of carbon support films, thin films coatings research, and some AFM studies where HOPG are used to taking place, the mica V-4 or V-5 is recommended. (Mica must always use freshly cleaved surfaces).


For AFM and SPM calibration, V-1 or V-2 is recommended. However, we believe that it is important that you know what kind of mica is being used in your lab. The information on the mica as given above should be used to make your choice.


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