Vacancy-Impurity Atom Interaction in Noble Metals and Their Alloys: Dependence on the Impurity Valence (1). Calorimetric Detection of Quenched-in Defects in Metallic Powders (2). Growth of Ii-Iv Compound and Electrooptical Single Crystals (3)

摘要

As a part of a wider experimental program on the behaviour of point defects in pure and impure noble metals equilibrium measurements of the influence of lattice vacancies and vacancy-impurity complexes on electrical resistivity of noble metals containing small percentages of noble-metal or transition-metal impurities have been performed. The binding energies of the impurity-vacancy complexes and the ratios of resistivity contributions of free to bound vacancies have been determined. The impurity-vacancy interaction results positive in six of the investigated solvent-solute systems, and null or negative in the other three. The results agree well with theoretical expectations and with other independent results in most cases. The few discrepancies are discussed. The possibility to detect quenched-in defects in platinum powder by microcalorimetric measurements is discussed, a powder quenching device is described and two projects for high sensitivity, high-temperature thermopiles, to be used in an isothermal microcalorimeter, are presented. Good-quality ZnTe and Zn(TeSe) single crystals and excellent-quality ADP, KDP, HIO3 and (NH4)2C2O4.H2O single crystals have been grown by various methods. The growth methods and the properties of obtained crystals are described and discussed. (Author)