Sintering in colloidal particles of rare earth hydroxycarbonate and its decomposition products

Abstract

The hydroxycarbonates of binary or ternary rare earths prepared as amorphous colloidal spheres by controlled homogeneous precipitation from urea solutions are shown to sinter without an incoherent interface at each step in their decomposition to the oxide. This behavior is followed whether the decomposition is accomplished by the electron-beam during observation in the high-resolution electron microscope or during heat treatment outside the microscope. The absence of distinct boundaries in clusters of particles without long range order is illustrated. Coherent boundaries are shown to persist even with the substantial morphological change which occurs when the particles become crystalline.