Silica-coated ferroelectric particles are promising building blocks for functional bulk composites such as dielectric resonators, supercapacitors, or multiferroics. The ferroelectric/silica interface was fully investigated by means of high-temperature in situ X-ray diffraction, high-resolution scanning electron microscopy, and X-ray photoelectron spectroscopy. Mechanisms occurring at the interface were visualized using high-resolution postmortem and in situ transmission electron microscopy performed at different temperatures. On the light of this interface investigation, we have used advanced sintering processes such as spark plasma sintering and microwave sintering to obtain nanostructured composite ceramics and to evaluate their dielectric properties.