Sapphire Growth Technique History

The history of sapphire growth technique has been more than 100years, since 1885, Fremy, Feil and Wyse applied method of hydroxide flame melting natural ruby ​​powder and potassium dichromate and created "Geneva Ruby".

Since then, in order to meet scientific and technological development and industrial production for the special requirements of sapphire crystal quality, size, shape, and improve the yield of sapphire crystal, utilization and reduce costs, for sapphire growth method, the related research has been stopped and the result is also very significant. The manufacturing capability is going higher and higher. Meanwhile, the matched sapphire growth furnace is going larger and larger for producing crystal with large diameter. Nowadays, the diameter of crystal has increased from 2 inches to 12 inches.

With the rapid development of the sapphire growth, the importance has gone to the lower cost but higher quality. Generally speaking, the methods to grow sapphire crystal are solution growth, melt growth, and growth of three gas phases. And the melt growth due to a rapid growth rate, high purity and crystal integrity and good features, and is used to grow large and the most common method to crystal growth of a particular shape of the crystal.

By growing sapphire crystal, tungsten crucible and heating field are most important for its quality. If you are in need of high quality crucible, please feel free to contact sales@chinatungsten.com.

Sapphire Crystal Growing Methods Comparison

Sapphire Crystal Growing Methods Comparison
Growing Method	Advantages	Disadvantages	Application
Kyropoulos	High quality, Large size, High yield, Low cost	Complicate operation, Low consistency, low qualified yield, Not suitable for C sapphire	Rublcon (LED sapphire base)
Czochralski	Production examination easily, Good Shape	High density, iridium gold crucible, High cost, Size restriction	HoneyWell
EFG	High quality	Complicated Equipment and technology	Kyocera
TGT	Simple equipment, easy operation, high yield, C crystal	Uniformity temperature, long period, high cost	Shanghai Institute of Optics and Fine Mechanics
VGF	Simple equipment, high yield	High density	Yunnan, China
VHGF	Crystal size and shape are not restricted	Right is kept in STC	STC
HEM	High quality, large size	High requirement on equipment, complicated techniques, high cost, sapphire easier to break	Crystal System
SAPMAC	Entire crystal, annealing same location, short circle, low cost	Easily influenced by temperature fluctuation	Northeast China

All the above methods to grow sapphire can use tungsten crucible.

More details, please contact sales@chinatungsten.com.

Why Sapphire is Suitable for Infrared Transparent Window

Therefore, the materials for infrared transparent window needs to be high qualified, and should meet the basic requirements as following:
1)High mechanical strength: infrared transparent window material should have sufficient strength, so that it can withstand the high-speed movement of the pressure load.
2) High thermal stability: can withstand the impact of aerodynamic heating and high temperature caused by the change, transmittance and refractive index by the temperature changes.
3) High chemical stability: the material is exposed to the air, so that the material should be able to prevent salt solution or etching gas corrosion, and should not be easy deliquescence
4) High optical transmittance: can efficiently transmit the ultraviolet to the infrared radiation
5) High optical properties: small optical scattering and good refractive index
6) Meet requirement of large size window

Sapphire growing in tungsten crucible, is a wonderful material that can meet all the above requirements. It is suitable for television, infrared imaging and radar. Furthermore, it can meet the high requirement of hypersonic missile wave-transparent. And this is why sapphire has become an excellent choice for high-speed fighter in advanced countries, missiles and other medium wave infrared transparent window material. 

More details, please contact us by email sales@chinatungsten.com. 

Growing Process of Sapphire by Using Tungsten Crucible

The above process shows the process of growing sapphire by using tungsten crucible. CTOMS is mainly producing tungsten crucible for this purpose. If you have got any comment, please feel free to send us email sales@chinatungsten.com.