Loss mechanism and lifetime estimation of Ce–W cathode in high temperature thermionic emission electrostatic precipitation

• Emission cathodes in thermionic emission electrostatic precipitation was researched.
• Microstructure of emission cathode was explored.
• Variation of emission characteristics was investigated.
• Lifetime of emission cathode in field of electrostatic precipitation was estimated.

Rare earth tungsten, 2.2% cerium–tungsten (Ce–W), was used as emission cathode material in thermionic emission electrostatic precipitation. The microstructures and emission properties were investigated. A model was established to estimate cathode lifetime in high temperature and oxygen-bearing atmosphere. Results show that there were not great changes in the inner microstructure of emission materials. But on the surface, tungsten was oxidized to tungsten trioxide and then tungsten trioxide and rare earth oxides evaporated and lost. Decrease of oxygen concentration was effective to prolong operation time of cathode. The increase of temperature reduced cathode lifetime remarkably.

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