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Sapphire Crystals

Product Highlights

 Sapphire crystalHTOT sapphire crystal is synthetic hexagonal structure crystal growing by high-temperature melting and crystallizing of high-purity alumina (Al2O3) with a purity over 99.999% in a crystal growth furnace. Sapphire crystal has remarkable characteristics of high sound velocity, heat resisting, corrosion resisting, high hardness, high light transmittance and extremely high melting point(2050℃). So sapphire crystal has been widely used for optical components, optoelectronics components, IR facilities, high-strength laser films and photomask.


HTOT sapphire crystal growth method is an advanced US technology based improved heat exchange method (HEM) . HEM sapphire crystal has several advantages:

-Sapphire boules's shape is regular.

-Sapphire quality is stable.

-Sapphire product utilization is high.

HTOT sapphire crystal properties:

Mechanical properties
  Optical properties
Density 3.97g/cm³ UV >70%
Vickers hardness 22GPa Visible~near mid-infrared >87%
Tensile strength 413.79MPa Refractive index 1.83@255nm
Compressive strength 2068.97MPa
Young's Modulus 74×106psi
Poisson's Ratio 0.28
Electrical Prperties Thermal properties

@25℃>1018ohm cm

@500℃>1012ohm cm

Melting Point 2050℃
Dielectric Constant

()C 9.3

(KHz-I GHz,25°)

Thermal Conductivity



()C 11.5

(KHz-I GHz,25°)

Dielectric Strength 480,000v/cm Specific Heat 1.99J/cm³℃
Item Parameter Testing Equipment
EPD <1000/c㎡ Leatz Polarrizing microscope

Rocking Curve


<15" X' TRA
Purity >99.999% GDMS

HTOT Sapphire Crystal's Orientation Difference:

Sapphire Crystal Orientation



Flexural Strength


Dielectric Constant
Different Orientation Performance
 C 2200 350 11.5 Isomorphism
 A  1800  500  9.3 Isomerism
 M  1800  500  9.3


HTOT Sapphire Crystal Sizes:

Weight Diameter Height Crystal orientation
115kg grades 100-200㎏ 380-400mm 210-260mm A-Plane
130kg grades 120-140㎏ 380-400mm 250-300mm A-Plane
165kg grades 140-170㎏ 440-460mm 260-300mm A-Plane
200kg grades 200-260㎏ 500-520mm 280-300mm A-Plane

This document is copyright © September 1, 2015 GHTOT. All rights reserved. This document is provided for information purposes only; contents are subject to change without notice. It is not warranted to be error-free, nor subject to any other warranties or conditions including implied warranties and conditions of merchantability or fitness for a particular purpose. 

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