coated with the cation rich layer thus achieving the stable surface conversion to cubic or t prime zirconia in another embodiment the thermally treated ceramic component 2 having the stable cubic or t prime surface layer is coated with a hermetic coating to further assure that the ceramic component 2 will remain stable and will not be subject to low temperature degradation the hermetic coating is comprised of known ceramic materials that are capable of forming a hermetic coating including silica alumina silicon nitride zirconia silicon oxynitride aluminum oxynitride silicon aluminum oxynitride and ultra nanocrystalline diamond thin film these ceramic coatings may be applied by combustion chemical vapor deposition physical vapor deposition electron beam evaporation ion beam assisted deposition ion implantation or chemical vapor deposition the coating can be deposited at room temperature for combustion chemical vapor deposition physical vapor deposition electron beam evaporation or ion beam assisted deposition chemical vapor deposition known to those skilled in the art is performed in a high temperature furnace the furnace is heated to 800 u00b0 to 1300 u00b0 c and chemical precursors are placed into the furnace in gaseous form the gases dissociate in the heat and deposit on the substrate or part combustion chemical vapor deposition illustrated in fig2 does not employ a furnace and may be practiced in an air or inert gas milieu rather a combustion gun 10.