Sapphire crystal is the common form of single crystal. It has a series of excellent physical and chemical properties, such as high strength, high hardness, high temperature resistant, friction resistance, corrosion resistance, good pervious to light performance, good electrical insulating performance and etc .Therefore, sapphire can be widely used in national defense, scientific research, civilian industry, and other areas of the various demanding. Over the past five years, as LED lighting substrate and consumer electronic touch screen marked expanded, sapphire crystal industry got the best opportunities than ever before.

Crystal structure:	Six-party crystal series
Crystal cell parameters:	a=4.785 Å , c=12.991Å
Melting point:	2045℃
Density:	3.98g/cm3
Mohs hardness:	9
Thermal expansion coefficient:	5.8×10-6/K
Specific heat:	0.418W.s/g/k
Thermal conductivity:	25.12W/m/k (@ 100℃)
Refractive index:	no=1.768  ne=1.760
dn/dt:	13x10-6/K(@633nm)
Pervious to light features:	T≈80% (0.3～5μm)
Dielectric constant:	11.5(∥c), 9.3(⊥c)

The sapphire melting point is 2045℃，it is such a high temperature that plenty of high melting point metal such as tungsten and molybdenum are used in the process of sapphire growing.

The methods of crystal growth:

− KY Method: Kyropoulos Method

− TGT Method

− EFG Method：Edge Defined Film-fed Growth

− HEM Method： Heat Exchange Method

− VHGF Method：Vertical Horiaontal Gradient Freezing Method

− Horizontal Bridgman method

KY Method 、HEM and EFG method are mainly used methods.

As the tungsten (melting point 3420℃) and molybdenum (melting point 2610℃) materials have high temperature resistant, low pollution, high temperature creep resistance and other properties, they are widely used for sapphire growing. We can provide all kinds of parts in the hot zone .

We can provide customers with a full set of tungsten or molybdenum materials which are needed in all kinds of crystal growth methods.

− Tungsten Heater

− Tungsten Crucible

− Tungsten Shields

− Molybdenum Crucible, Molybdenum Tube, Molybdenum Ring, Molybdenum Core Rod

− High Temperature Binding Wire

− Other Custom Tungsten Products

− Tungsten and Molybdenum Alloy

We have the world's largest tungsten crucible and tungsten tube manufacturing capability. Our hot zone can satisfy your needs no matter which type furnaces you are using,30kg or 300kg.

Diameter(mm)	Tickness(mm)	Height(mm)
30-50	8-10	<1300
50-100	8-15
100-150	10-15
150-200	12-20
200-300	15-20
300-400	15-30
400-450	15-30
450-550	15-30
550-650	25-35
650-750	25-35

Tungsten and molybdenum semi-finished products are manufactured via the powder metallurgy process.

We use high tech forging, rolling and heat treatment methods to continue the deep processing, shape the materials and improve their performance.

We use high precision mechanical processing technology and equipment to complete the finished product processing

➢ With sixty-year experiences from AT&M Refractory Materials Branch and thirty-year experiences from TLWM, ATTL owns the professional crucible manufacture technology and is the first supplier of tungsten crucible in China.

➢ We have the nation's largest advanced tungsten & molybdenum materials production lines which can satisfy your different product requirements.

➢ Precision machining technology, the use of CNC laser cutting, high precision, to ensure that the heat evenly spaced, provides the high level of environment for the sapphire growing.

➢ We can design and improve the hot zone together with you. We have more than 20 thermal field technology engineers always ready for your production line, make recommendations for you.

➢ We never stop footsteps of technical innovation. As a state-owned company, we take responsibility of leading the development of domestic refractory metal technology.

➢ Company certificated by the ISO9001, ISO14001 and OHSAS18001 system authentication