The book provides an account of quasielastic neutron scattering (QENS) which has made many important contributions to the atomistic elucidation of diffusion processes in solids. The unique feature of QENS is that it probes the diffusion process on atomistic scales of space and time simultaneously. The aim of this book is to inform of the potential of QENS. Chapters 3-6 present the derivation of all equations in great details. Chapter 2 deals with neutron sources, and Chapter 7 with some experimental details of QENS. The second part addresses the expert and summarizes the scientific applications of quasielastic neutron scattering to special solid state material systems, as for example to diffusion in metals or to diffusion in solid state ionic conductors. By far the most favourable element for QENS is hydrogen: hydrogen is very mobile in metals and ceramics, so the restricted energy/time resolution of QENS is no limitation; hydrogen has a huge scattering cross section, so the limited intensity of existing neutron sources is no limitation; hydrogen leads to almost purely incoherent scattering which facilitates the theoretical treatment and interpretation of neutron scattering events appreciably.

The present work shows, for the first time, a comparative experimental study on the electrodeposition of aluminium in three different water and air stable ionic liquids, namely 1-butyl-1-methylpyrrolidinium-bis(trifluoromethylsulfonyl)imide ([BMP]Tf2N), 1-ethyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide ([EMIm] Tf2N), and trihexyl-tetradecyl-phosphoniumbis(trifluoromethylsulfonyl)imide (P(14,6,6,6) Tf2N). The ionic liquids [BMP]Tf2N and [EMIm]Tf2N show biphasic behaviour in the AlCl3 concentration range from 1.6 to 2.5 mol L(-1) and 2.5 to 5 mol L(-1), respectively. The biphasic mixtures become monophasic at temperatures >/=80 degrees C. It was found that nanocrystalline aluminium can be electrodeposited in the ionic liquid [BMP]Tf2N saturated with AlCl3. The deposits obtained are generally uniform, dense, shining, and adherent with very fine crystallites in the nanometer size regime. However, coarse cubic-shaped aluminium particles in the micrometer range are obtained in the ionic liquid [EMIm]Tf2N. In this liquid the particle size significantly increases as the temperature rises. A very thin, mirrorlike aluminium film containing very fine crystallites of about 20 nm is obtained in the ionic liquid [trihexyl-tetradecyl-phosphonium]Tf(2)N at room temperature. At 150 degrees C, the average grain size is found to be 35 nm.

Better than water: A method for the electrodeposition of nanocrystalline metals and alloys from ionic liquids has been developed (see schematic representation). This method enables the synthesis of aluminum nanocrystals with average grain sizes of about 10 nm, Al‐Mn alloys, as well as Fe and Pd nanocrystals.

Porous golden interiors: Highly organized macroporous metal structures can be synthesized by the preparation of ordered colloidal crystals by the Langmuir–Blodgett technique and subsequent precision electrodeposition controlled by current oscillations. After the assembly of a bioelectrocatalytic chain in the pores, these tailored surfaces can be used as transducers with currents increased by more than one order of magnitude (see diagram).

Pulsed electrodeposition (PED) is used to prepare nanocrystalline iron with an average grain size of 19 nm and thermal stability up to 550 K. At 663 K e T e 783 K the kinetics of grain growth, with respect to size and size distribution, is studied in situ by means of real-time synchrotron X-ray diffraction. The Bragg peak line shapes of the large number of diffractograms are analyzed using a Warren/Averbach procedure improved with respect to reliability and efficiency. We observe two regimes of grain growth: at less elevated temperatures grain growth is smooth and moderate up to limiting size values between 50 and 100 nm, depending on temperature. The initially rather narrow width of the size distribution increases slightly, and the activation energy of grain growth, about 100 kJ/mol, corresponds to the literature value for grain boundary self-diffusion in nanocrystalline Fe. At higher temperatures the grains grow first rapidly and then slowly up to limiting values between 200 and 400 nm, depending on temperature. The size distribution becomes rather broad, and the activation energy for grain growth, about 175 kJ/mol, corresponds to the literature value for grain boundary self-diffusion in coarse-grained polycrystalline Fe. We do not find evidence for a change of the type of distribution which indicates normal grain growth. The quality of our diffraction data allows a critical evaluation of different kinetic models of grain growth.