The　Scandia　doped　thermionic　cathodes　have　received　great　attention　owing　to　their　high　electron　emission　density　in　past　two　decades.　Here,　Scandia　doped　Re3W　matrix　scandate　(RS)　cathodes　are　fabricated　by　using　Sc2O3　doped　Re3W　powders　that　prepared　by　spray　drying　method.　The　micromorphology,　surface　composition　and　chemical　states　of　RS　cathode　are　investigated　with　various　modern　technologies.　It　reveals　that　the　reduction　temperature　of　RS　powders　is　dramatically　increased　by　Sc2O3.　On　the　surface　of　RS　cathode,　a　certain　amount　of　Sc2O3　nanoparticles　and　barium　salt　submicron　particles　are　observed.　According　to　the　in　situ　Auger　electron　spectroscopy　analysis,　the　concentration　ratio　of　Ba:Sc:O　is　determined　to　be　2.9:1.1:2.7.　The　X-ray　photoelectron　spectroscopy　data　indicates　that　low　oxidation　state　of　Sc　is　clearly　observed　in　scandate　cathodes.　The　high　atomic　ratio　of　Ba　on　RS　cathode　surface　is　suggested　due　to　the　high　adsorption　of　Re3W　to　Ba.　Moreover,　RS　cathode　shows　better　adsorption　to　Sc　by　comparison　with　conventional　tungsten　matrix　scandate　cathode.　For　RS　cathode,　the　main　depletion　of　Sc　is　suggested　to　-OSc　desorbing　from　RS　cathode　surface.　RS　cathode　is　expected　to　be　an　impressive　thermionic　cathode　with　good　emission　properties　and　ion　anti-bombarding　insensitivity.　(C)　2018　Elsevier　B.V.　All　rights　reserved.