The vacuum vessel sealing materials

① a sufficiently low saturation vapor pressure. Generally low vacuum, the saturated vapor pressure at room temperature should be less than 1.3 × 10-1 ~ 1.3 × 10-2Pa. High vacuum, should be less than 1.3 × 10-3 ~ 1.3 × 10-5Pa.

 

② chemical and thermal stability. Sealing parts, does not occur due to a reasonable temperature rise rain softening, chemical reaction or volatile, and even the atmosphere to break through.

 

③ there are certain mechanical and physical properties. Cooling after hardening of the solid sealing material, plastic sealing material or dried and hardened, sealing wax, etc., to be able to smoothly close to the sealing surface, no bubbles, no wrinkles. When the temperature changes, should not become brittle or cracked. Liquid or colloidal sealing material should be kept to the original viscosity.

 

④ some of the sealing material should be soluble in certain solvents, for the replacement of easy cleansed.

 

In addition to the above requirements on the application of the material in the vacuum, in some cases must also consider the electrical properties of insulating properties, optical properties, magnetic properties and thermal conductivity, etc..

 

Of course, in addition to the above properties of the material, but also consider the cost of materials, utilization, and the optional possibility.