Applications of In Situ Neutron Diffraction to Optimisation of Novel Materials Synthesis

Summary

For almost a decade the development of ultra-fast, high-flux neutron diffractometers has largely exceeded the experimental requirements of most users. Fortunately, in recent years the unique capabilities of these instruments have become more widely recognised and they are being applied as a reliable means of kinetic analysis. When combined with PSDs capable of a wide angular range (5–160^∘ 2θ) and very fine time-resolution ( < 80 ms), high-flux neutron diffractometers begin to emerge as an industrially relevant technique in the design, characterisation and certification of advanced materials. The ability to implement such detailed analysis has been significantly aided through the concurrent development of batch Rietveld data processing suites and the Quantitative Phase Analysis (QPA) technique.

This present research will outline all developmental work using the D20 diffractometer (ILL, France) in the exploration of M _n + 1 AX _n Phase materials. D20 has enabled us to explore the ultra-fast reaction kinetics of a Self-propagating High-temperature Synthesis (SHS) of model M _n + 1 AX _n Phase systems at a < 900 ms time resolution. In turn, this technique has been further refined and applied in the confirmation of a novel solid state M _n + 1 AX _n Phase precursor design. The ability to simultaneously explore the in situ chemical and thermal environments of large volume samples has provided us with a means of rapidly prototyping novel synthesis techniques. By way of example, the successful application of solid state precursors has reduced the M _n + 1 AX _n Phase synthesis times and temperatures by approximately 50 and 44%, respectively. The development and application times for these precursors could not have been achieved without application of these diffractometers’ capabilities.

More generally, time-resolved in-situ neutron diffraction has the potential to redefine many research techniques in both materials science and solid state physics if two experimental methodologies can be perfected: (1) concurrent experimentation and (2) complementary analysis. More specifically, we should aim to couple in situ neutron scattering with the simultaneous analysis of chemical, thermal, physical or environmental factors, while analysis using complementary techniques (e.g. neutrons and X-rays) will ideally produce higher scientific standards in characterisation. Together, these methodologies will significantly reduce the development time and complexity of novel materials syntheses, while ultimately lowering associated costs. The key to achieving these goals is the design and implementation of robust in situ sample environments capable of exploring a wide range of synthesis and simulated service environments. In conclusion, the designs and commissioning of equipment intended for these aims will also be discussed.