Thermal Analysis of 3‐mol%‐Yttria‐Stabilized Tetragonal Zirconia Powder Doped with Copper Oxide

Thermal analysis was performed upon 3‐mol%‐yttria‐stabilized tetragonal zirconia polycrystals (3Y‐TZP) which had been doped with CuO using an aqueous adsorption technique. Cyclic differential thermal analysis (DTA) scans indicated that the CuO present on the powder surfaces first transforms to Cu 2 O and then melts. The molten Cu 2 O then reacts with yttria at the powder surfaces to form a new phase containing Y, Cu, and O. Because Y takes time to diffuse to the particle surfaces, the apparent melting point of this new phase appears at higher temperatures in initial DTA scans than in subsequent scans. Vaporization of the molten copper‐oxide‐rich phase at the temperatures studied causes a gradual shift in composition from Y 2 Cu 4 O 5 to the less copper‐rich Y 2 Cu 2 O 5 phase. The presence of the Y 2 Cu 2 O 5 phase in CuO‐doped 3Y‐TZP allows for previous sintering and superplasticity results to be explained.