In situ oxidation and reduction of the oxides of cerium, praseodymium and terbium by high‐voltage electron microscopy

Abstract

SUMMARYIn situ oxidation and reduction of the oxides of cerium, praseodymium and terbium in a controlled atmosphere and temperature have been studied utilizing a high‐voltage electron microscope. Experiments were carried out in the environmental cell of the Berkeley KRATOS EM 1500 HVEM at temperatures between 298 K and 1023 K in an atmosphere of oxygen, hydrogen or vacuum. Electron diffraction patterns revealed the course of small fragments of the crystalline oxides. In nearly all cases, the degree of reduction recorded was greater than expected from equilibrium tensimetric studies in the absence of an electron beam. Furthermore, reoxidation appeared to be more sluggish and to a lesser extent than is observed in specimens outside the microscope.