What is the difference between epoxy sealed and ceramic sealed contactor?

1.Seal material

Epoxy
     (Alumina powder)

Ceramic
     (Alumina powder)

2.Arcing

Magnetic arc blow

Magnetic arc blow

3.Packing process

Epoxy curing seal
     （Double injection）

Ceramic welding and seal
     （Laser welding）

4.Filling gas

Nitrogen
     （Ionization can be higher than air）

Hydrogen
     （Ionization can be higher than nitrogen）

5.Isolation voltage

12-1500Vdc

12-1500Vdc