Principal benefit of Monocrystal Synthetic Mica (Fluor-phlogopite Crystal)

IKK has been continued research and development on Synthetic Mica towards commercialization of the technology. At present*, IKK is the only company in Japan that has fabrication sector for the product, and the product has earned a high reputation in the marketplace.
*: as of March 2014

  • flat and smooth crystalline plane
  • very few impurities / nearly clear and colorless compared to natural mica
  • extremely high heat resistance (of 1100°C), being far superior to that of heat-resistant glass
  • highly resistant to high temperature and high pressure steam
  • excellent in erosion resistance
  • filmic and sheet-like
  • resistant to practically any acid or alkali
  • size of generable single crystal: 70 x 70 x 7 mm
  • specific gravity: 2.85
  • melting point: 1375°C

Note: On display at Nagoya University Museum

Specifications of Monocrystal Synthetic Mica (Fluor-phlogopite Crystal)

Characteristics comparison between Synthetic Mica (Fluor-phlogopite) and Natural Mica
Synthetic Mica (Fluor-phlogopite Crystal) Natural Mica (Muscovite) Natural Mica (Phlogopite)
Chemical Formula KMg3AISi3O10F2 KAL3Si3O10(OH)2 KMg3AISi3O10(OH)2
Specific Gravity 2.85 (g/cc) 2.7〜3.0 (g/cc) 2.7〜2.9 (g/cc)
Refractive Index 1.522〜1.554   1.522〜1.615      
Temperature Characteristics
Maximum Working Temperature 1100 (℃) 550 (℃) 800 (℃)
Melting Temperature 1375 (℃) - (℃) - (℃)
Dehydration Temperature - (℃) 700〜900 (℃) 800〜900 (℃)
Thermal Conductivity 4.30 (J/m.s.K): (cleavage planes direction) 3.6 (J/m.s.K) - -
0.67 (J/m.s.K): (vertical direction) - - - -
Thermal Diffusivity 0.018 (㎠/s) 0.015 (㎠/s) - -
Specific Heat(cp ) 1.62 (J/㎤K) 1.63 (J/㎤K) - -
Mohs' Hardness 3.4 (mohs) 2.0~3.0 (mohs) 2.0~3.0 (mohs)
Ultimate Tensile Strength 27〜31 (kg/㎟) 35〜39 (kg/㎟) 20〜28 (kg/㎟)
Elastic Modulus 17500 (kg/㎟) 16000〜21000 (kg/㎟) - (kg/㎟)
3-point Bending Strength
(At Room Temperature)
45.6 MPa 79.0 MPa - -
Thermal Shock Bending Strength(200℃) 29.8 MPa 105.3 MPa
Dielectric Characterics of Synthetic Mica (Fluor-phlogopite Crystal)
Measuring Frequency Dielectric Constant Dielectric Loss
1 5.43 0.0089
10 5.38 0.0039
100 5.38 0.0037
1000 5.38 0.0249

Applications of Monocrystal Synthetic Mica (Fluor-phlogopite Crystal)

  • Observation window material for high temperature / high pressure boilers
  • Observation window material for radiation (X-ray) equipment
  • Substrate for single crystal growth
  • Various optical components
  • For other materials to be permeable at high temperature environment

Additional Information about Monocrystal Synthetic Mica (Fluor-phlogopite Crystal)

Image by Laser Microscope

Image by Laser Microscope

Measuring surface roughness of cleavage plane of single crystal Synthetic Mica by laser microscope.
Confirmed flat and smooth plane practically equivalent to quartz glass substrate.

Arithmetical mean of roughness Ra = 3 nanometers

Crystal Structure of Synthetic Mica

Crystal Structure of Synthetic Mica

  • Chemical Formula KMg₃AlSi₃O₁₀F₂ (Fluor-phlogopite Crystal)
  • SiO₄ regular tetrahedrons are connected sheet-like and an Mg ion combines two SiO sheets to form a layer. Because these layers are loosely connected by K ions, layers can be cleaved easily and as a result, smoothly-surfaced crystals are generated.

Transmittance of UV-visible and NIR

Measuring equipment: Spectrophotometer Hitachi U-4000

Transmittance chart of UV-visible and NIR

- Transmittance of Synthetic Mica is higher than that of Natural Mica in UV-visible range.
- In NIR range, too, Synthetic Mica shows slightly higher transmittance than Natural Mica.
- Absorption peaks are observed at 1400nm and 2200nm with Natural Mica, while no such absorption is seen with Synthetic Mica.

Transmission rate of infrared ray

Measuring equipment: FT-IR (Fourier transform infrared spectrophotometric) JEOL Ltd. JIR-650

Chart of infrared ray transmission rate of natural mica #1 Chart of infrared ray transmission rate of syntehtic mica #1 Chart of infrared ray transmission rate of natural mica #2 Chart of infrared ray transmission rate of synthetic mica #2

- Data at around 4µm is wavy due to interference
- Synthetic Mica is higher in transmittance at entire wavelength region if compared with samples of same thickness
- An absorption peak is observed at around 2.7µm with Natural Mica only. This is considered to be a coherence which exists only with Natural Mica, because no such absorption is seen with Synthetic Mica.
- It is presumed to be a coherence of OH-radicals.

INQUIRY / ITOH KIKOH CO., LTD.  Technology Division
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ITOH KIKOH CO., LTD. Technology Division
ADDRESS: Nu-no-wari 412-4, Minamishibata-machi, Tokai, Aichi 476-0001, Japan
TEL: +81 52 604-7942
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