Physical & Chemical Properties of Tungsten and Molybdenum Plates for Insulation Screens：

Type	Purity	Density	Vapor	Plastic Brittle Transition  Temperature	Recrystallization  Temperature
Tungsten Sheet	≥99.95%	≥19.2g/cm3	10-6Pa	200-400℃	~1350℃
Molybdenum Sheet	≥99.95%	≥10.2g/cm3	10-2Pa	20-200℃	~1050℃

The evaporation rate of molybdenum outweighs that of tungsten. Recommend using tungsten products  in the hot-zone with temperature higher than 1800℃.

Quality Control:

- Thickness available or customized thickness:    

a: Tungsten Sheet (mm)：   0.25  0.3  0.5  1.0  2.0   

b：Molybdenum Sheet (mm)： 0.25  0.3  0.5  1.0  2.0   

Thickness tolerance is 10% of the sheet thickness.

- For molybdenum, the biggest diameter of shielding made with one single sheet is Φ800 mm. While Tungsten is Φ400 mm.

- For molybdenum, the biggest height of shielding made with one single sheet is Φ700 mm. While tungsten is Φ600 mm.

- For molybdenum, the biggest diameter of upper or bottom shielding made with one single sheet  is Φ700 mm. While tungsten is Φ600 mm.

- Super large size shielding could be manufactured by joining several sheets according to the drawings.

Storage & Usage Recommendations:

- Tungsten and molybdenum sheets (especially tungsten sheet ) are brittle and must be handled gently with care.

- Shielding must be stored in a dry area (humidity less than 60%), otherwise it is easy to be oxidized.

- After one round, shielding become brittle whether it is tungsten or molybdenum material, due to the complete recrystallization and need to be handled carefully.

- Tungsten and Molybdenum oxidize easily at high temperature. The vacuum degree should be higher than 10^-3 Pa at high temperature.

- The evaporation rate of molybdenum outweighs that of tungsten. So tungsten sheets are better than molybdenum sheets when the temperature is over 1800℃.