The aim of the present investigations is to systematically vary the leaching conditions (time, temperature, leaching medium, effect of microwave radiation) for pre-sintered BaTiO3 particles in order to obtain a controlled growth of amorphous TiO2-surface layers and to further improve the sliding properties of the grains, and thus the density and microstructure of the final ceramics. Microstructure and nanochemistry of the resulting surface layers and final ceramic bodies will be characterized by high voltage (HVEM), high resolution (HREM) and analytical electron microscopy. The supplementary investigations of leaching under microwave radiation were carried out as microwave energy can enhance the mass transport and the solid-state reaction rates near surfaces and interfaces [9,10]. To reduce the number of pores and to improve the electrical properties of the resulting ceramics some selected powder compacts were hot isostatically pressed (hip) in addition.