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.　(C)　2014　Elsevier　BM.　All　rights　reserved.