High temperature thermodynamic properties of some of the rare earths

摘要: The design and construction of a high temperature vacuum ice calorimeter is described. It was calibrated from 1100 to 1700 deg C with alpha -Al/sub 2/O/ sub 3/, the results were compared other studies made on this material in range indicated. This instrument used determine heat content yttrium metal 1675 C. contents lanthanum, praseodymium, europium, ytterbium, studied 0 110O using conventional Bunsen calorimeter. enthalpy each expressed as function by fitting data empirical equations least-squares treatment; form these varied for regions studied. Thus, room crystalline transformation, cubic expression would usually fit well; region liquid, linear could be used. From expressing data, thermodynamic functions derived evaluated at 50 intervals well transformation temperatures. heats weremore » calculated 753, 760, 418, 1189 calories per mole. fusion 1482, 1652, 2204, 1830, 2732 mole, respectively. Quenching fcc modification lanthanum hcp reduced an annealing procedure that provided reproducible results. However, exact amount higher energy quenched not known. Anomalies found curves europium ytterbium 503 553 K. These small breaks attributed contributions capacity arising 4f electronic transitions resulting presence some trivalent ions predominantly divalent metal. observed confirmed density measurements two metals are primarily state.« less