Preparation of TEM samples for hard ceramic powders

It is challenging to prepare a good sample for high-resolution electron microscopy of polycrystalline ceramic powders containing hard particles or particles with a strong preferential cleavage. Here we demonstrate that embedding the particles in a Cu matrix in a pressed pellet allows for straightforward conventional ion milling. The method is applied to powders of Mg10Ir19B16 and Na0.5CoO2 to show its feasibility, whereby transmission electron microscopy (TEM) samples with crystalline areas thinner than 10 nm can be obtained easily.