A method is described wherein a ceramic oxide nanocomposite coating has been produced via a co-precipitation route. The first step in the process consists of forming a solid solution by use of plasma melting, homogenization, and rapid quenching of two ceramics that are normally immiscible. In the best case, the resulting structure is a true solid solution in a new, metastable crystalline structure. The quenched particles can be deposited as a coating or sprayed into water or onto a chill block to form a powder. When the material is sintered via a pressureless process, such as that for a coating, the phase decomposition proceeds quickly, resulting in a homogeneously distributed two-phase structure of micron sized particles. However, when the powders are compacted and sintered at very high pressures (1-8 GPa) and low temperatures (T ~ 0.3 - 0.5 Tm), the increased nucleation of the precipitates results in a composite in which both phases have grain sizes less than 25nm. This paper will review the underlying phenomenon behind the method and the resulting kinetics.