Among many materials present in our daily lives, technical ceramics occupy numerous fields. Their applications range from energy, biomedical to transport (automotive, aeronautics, space, etc …) sectors. Sintering is a key processing of the powder metallurgy to produce ceramics with desired physical performances. It determines both the densification (porosity rate) and the microstructure (grain size) as well as the shape of the part. In the last decades, the development of more energy efficient and environmentally friendly manufacturing processes has encouraged intensive research on low-temperature and/or ultrafast sintering processes. These efforts have led to the elaboration of new materials, multi-materials and composites for applications in various socio-economics fields.
 
In this communication, we will first present a state of the art of the literature on the Cold-SPS process. In a second part, we will discuss the original strategies developed and demonstrate the possibility of producing nanostructured oxide ceramics through three examples (lanthanum phosphate: LaPO4; Yttria: Y2O3 and stabilized zirconia: 3Y-ZrO2) through engineered grain boundaries by reactive Cold-SPS of hydrated or hydroxide precursors. The complex chemical mechanisms involved in the process of densification are highlighted. Finally, the mechanical properties of the nano-ceramics obtained are discussed in relation to their structures and microstructures.