title: Recent progress on RE2O3-Mo/W emission materials.
abstract: RE2O3-Mo/W cathodes were prepared by powder metallurgy method. La2O3-Y2O3-Mo cermet cathodes prepared by traditional sintering method and spark plasma sintering (SPS) exhibit different secondary emission properties. The La2O3-Y2O3-Mo cermet cathode prepared by SPS method has smaller grain size and exhibits better secondary emission performance. Monte carlo calculation results indicate that the secondary electron emission way of the cathode correlates with the grain size. Decreasing the grain size can decrease the positive charging effect of RE2O3 and thus is favorable for the escaping of secondary electrons to vacuum. The Scandia doped tungsten matrix dispenser cathode with a sub-micrometer microstructure of matrix with uniformly distributed nanometer-particles of Scandia has good thermionic emission property. Over 100 A/cm2 full space charge limited current density can be obtained at 950Cb. The cathode surface is covered by a Ba-Sc-O active surface layer with nano-particles distributing mainly on growth steps of W grains, leads to the conspicuous emission property of the cathode.
authors.affiliation: School of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China.
authors.forename: Jinshu
authors.initials: J
authors.lastname: Wang
authors.forename: Xizhu
authors.initials: X
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Yuntao
authors.initials: Y
authors.lastname: Cui
authors.forename: Yiman
authors.initials: Y
authors.lastname: Wang
authors.forename: Meiling
authors.initials: M
authors.lastname: Zhou