Phase Composition and Structure of the Ce-83.3 at%Ir Alloy Obtained by Electron Beam Melting

Photocathodes made of the Ir-Ce system alloys have high thermal resistance, electrical, and thermal conductivity along with high electron emission properties and are widely used as sources of electrons. In this paper, the phase composition and structure of the Ce-83,3ат%Ir alloy intended for use as a photocathode material are studied. The alloy obtained by electron beam melting has a component ratio corresponding to the CeIr5 intermetallic compound. Despite this, a dispersed multiphase material is formed during crystallization. X-ray phase analysis shows the presence of three phases, such as Ir, CeIr5, and Ce2Ir7, in the photocathode material. Optical microscopy studies of the photocathode microstructure reveal that the basis of the alloy is the CeIr5 + Ir eutectic. The CeIr5 phase forms a matrix in which Ir crystals are included. The Ir phase has the form of rods with an average diameter of 0.7 microns. The high dispersion of the structure can increase the emission properties of the photocathode.