SHAPE CHANGES BY (100) LITHIUM-FLUORIDE RIDGE-CHANNEL ARRAYS AND OF LITHIUM-FLUORIDE PARTICLES AT SINTERING TEMPERATURES

Parallel channels of rectangular cross section were etched into an LIF {100} single-crystal surface, by a photolithography technique, to produce ridge-channel arrays of controlled size and shape. The shape changes undergone by these arrays and by LIB isolated particles and powder beds at sintering temperatures were studied by SEM. The ridge-channel arrays and particles developed either faceted or rounded shapes, depending on temperature and atmosphere. Adsorption of an impurity, presumably H2O or O-2, although it causes faceting,(1) increases the rate of mass transport from the ridges to channels. The influence of array geometry on mass transport rates is compared to models to show that the rate-limiting mass transfer step is probably a surface step when the surfaces remain faceted and may be a surface step when the surfaces are rounded.