RESEARCH ON THE SAMARIUM-TYPE INTERMEDIATE PHASES OF INTRA-RARE-EARTH BINARY SYSTEMS

Four new binary intra-rare earth systems were investigated by metallography, hardness, and density measurements to confirm the presence of the intermediate samarium-type phase. The systems were: La-Lu, Nd-Lu, Sc-Gd, and Sc-La. The lutetium systems exhibited isomorphism with previous binary intra-rare earth systems, whereas the scandium systems did not. Thermal analysis and resistivity techniques were employed to determine the temperature at which the samarium phase forms in representative intra-binary systems. The thermal analysis and resistivity curves did not indicate reproducible thermal arrests or inflections. The thermodynamics of the intra-binary rare earth systems are being studied by liquid metal solution calorimetry. It was found that the solution of light rare earths were relatively easy in tin, whereas the heavy rare earths were very slow. Other liquid metal calorimeter baths are presently being investigated such as bismuth and indium. Indium shows much more promise for the solution of heavy rare earths. (Author)