FY07 LDRD Final Report Synthesis under High Pressure and Temperature of New Metal Nitrides

Crowhurst, J C ; Sadigh, B ; Aberg, D ; Zaug, J M ; Goncharov, A F

关键词: ACCURACY;    CHEMICAL REACTIONS;    DIAMONDS;    IRIDIUM;    IRON;    MELTING;    NITRIDES;    PALLADIUM;    PLATINUM;    SCATTERING;    SYNTHESIS;    TRANSITION ELEMENTS;    X-RAY DIFFRACTION;    X-RAY PHOTOELECTRON SPECTROSCOPY;   

DOI  :  10.2172/945755
RP-ID  :  LLNL-TR-407463
PID  :  OSTI ID: 945755
Others  :  TRN: US200904%%143

学科分类：化学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

The original aim of this LDRD was to determine with unprecedented precision the melting curve of iron to geophysically relevant pressures. In the course of developing much of the technology and techniques required to obtain this information we have encountered and studied novel chemical reactions some of whose products are stable or metastable under ambient conditions. Specifically we have synthesized nitrides of the platinum group metals including platinum, iridium, and palladium. We have also carried out in depth first principles theoretical investigations into the nature of these materials. We believed that the scientific impact of continuing this work would be greater than that of the original goals of this project. Indeed the work has led to a number of high profile publications with additional publications in preparation. While nitrides of the transition metals are generally of tremendous technological importance, those of the noble metals in particular have enjoyed much experimental and theoretical attention in the very short time since they were first synthesized. The field was and clearly remains open for further study. While the scientific motivation for this research is different from that originally proposed, many of the associated methods in which we have now gained experience are similar or identical. These include use of the diamond anvil cell combined with technologies to generate high temperatures, the in-situ technique of Raman scattering using our purpose-built, state-of-the-art system, analytical techniques for determining the composition of recovered samples such as x-ray photoelectron spectroscopy, and finally synchrotron-based techniques such as x-ray diffraction for structural and equation of state determinations. Close interactions between theorists and experimentalists has and will continue to allow our group to rapidly and reliably interpret complicated results on the structure and dynamics of these compounds and also additional novel materials. Although the purely scientific dividends of this project have been substantial, there remains the possibility of a technological application--now that nitrides with likely desirable properties have been shown to exist, large-scale synthesis techniques can be considered.