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Item Open Access Boron in Palladium: interaction, phase formation and phase transformation(2001) Beck, Markus; Mittemeijer, Eric J. (Prof. Dr. Ir.)The principles for the formation of interstitial solid solution have been described in the past by rules, taking in consideration elastic relationships between solvent and solute atoms. These rules are not applicable on the formation of the solid solution of the late transition metals (a-Co, Rh, Ir, Ni, Pd, Pt) and boron. The focus of this work is the binary system Pd-B. It shows the largest homogeneous range of the solid solution of transition metals with boron. The interstitial nature of this solid solution as well as the solid solutions of Pd(C) and the late transition metals (see above) with boron is clarified. It is shown that the chemical interaction plays a more important rule than the geometrical (elastic) interaction in the formation of the interstitial solid solutions. The structure of the palladium-rich borides Pd5B, Pd3B and Pd5B2 has been clarified and refined using X-ray diffraction analysis. Further the formation of the amorphous boride Pd2B has been observed fulfilling the Nagel-Tauc criterion. The solid solution Pd(B) decomposes at lower temperatures in two phases isotypical with the homogeneous solid solution. This phenomenon has been primarily analyzed using X-ray diffraction. The decomposition process is described by use of a structure model for simulating the X-ray diffraction-line profiles. The microstrain in the decomposed state has been measured and compared with that of the initial, quenched supersaturated solid solution. The dislocation density determined by the X-ray line-profile analysis of the homogeneous solid solution has been compared with values resulting from TEM investigations. Temperature uncertainty and unknown specimen displacement are the most severe errors in high temperature X-ray diffractometry, in particular when using a strip heater mounted on a Bragg-Brentano goniometer. A new method is presented which enables the simultaneous determination of the specimen displacement and the temperature of the sample.