Multicomponent refractory alloys prepared from single sours precursors under mild conditionsWednesday (28.09.2016) 17:45 - 18:00 Part of:
Multicomponent alloys containing platinum group metals and rhenium have high hardness and high thermal stability, and can be applied as high-temperature and high-hardness materials. Platinum group metallic alloys are known to be used as the working elements of high-temperature thermocouples and high-temperature and chemically resistant materials for crucibles. Recently, various multicomponent composites containing platinum group metals have been also proposed as active and selective heterogeneous catalysts. It is well known that the properties of metallic solid solutions are affected by their composition and preparatory conditions, as well as by the presence of impurities. The composition and temperature dependence of alloy properties is widely studied in order to analyse and predict the behaviour of metallic phases. However, difficulties in preparing solid solutions have led to poor and inconsistent information about multicomponent systems based on platinum group metals and the corresponding physical properties of its metallic phases.
Here, a single source precursors strategy for the preparation of multicomponent platinum group metallic alloys under mild conditions using multimetallic double complex salts [1-3] will be presented. As an example, a co-crystallisation of two isoformular isostructural compounds [Ir(NH3)5Cl][ReCl6] and [Ir(NH3)5Cl][IrCl6] results in the single-phase salt [Ir(NH3)5Cl][IrCl6]x[ReCl6]1–x. Thermal decomposition of the latter gives Ir0.5+0.5xRe0.5–0.5x alloy. This method allows us to synthesize a broad range of metallic compositions including metastable and nano-structured and can also be applied to complex systems including multi-component alloys.
Several binary and ternary systems were investigated under high-temperature (up to 3000 K) and high-pressure (up to 140 GPa) to prove their applicability under extreme conditions. Detailed investigation of binary systems gives an essential fundament for a preparation of more complex systems including models for multicomponent ultra heavy minerals and catalysts.
 Yusenko et al. (2015): J. Alloys and Comp. 622, 155;  Yusenko (2011): Platinum Met. Rev. 55, 186;  Yusenko (2013): Platinum Met. Rev. 57, 57.
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