Metal-rich TiNiCuySn Half-Heusler nanocomposites have promising power factors and may find application in thermoelectric waste heat recovery. The aim of the experiment is to determine the distribution of the excess copper, which is either contained within the TiNiSn matrix or fully segregated into a distinct TiNiCuSn phase. Laboratory X-ray powder diffraction reveals substantial changes in the copper distribution when comparing cold-pressed and hot-pressed samples but cannot be used to determined accurate compositions due to the similar scattering strength of Ti, Ni and Cu. Neutron powder diffraction does provide good scattering contrast and is needed to determine accurate experimental compositions for the matrix and the fully segregated phase.
