Ankit Kumar

The homogeneous zirconia thin films having a thickness of 250 nm synthesized on silicon substrate using an e-beam deposition technique and annealed in the temperature range of 600–1000°C have been investigated for phase transformations of zirconia. It has been observed from the X-ray diffraction (XRD) pattern and the Raman spectroscopy that phase transformation from cubic phase to monoclinic phase of zirconia occurred in the temperature range 600–800°C, despite the amorphous nature of deposited films. From Rietveld refinement studies, it has been found that crystalline phase in zirconia films annealed at 600°C, is cubic in nature. Further, the morphological studies revealed that the grain size of zirconia increases with an increase in the annealing temperature. It is expected that the present studies on structural and morphological properties of zirconia having an emphasis on its cubic phase stabilization shall help to explore its possibility in device applications.

The phase evolution studies of zirconia, with 4–16 mol-% doping of calcium, have been carried out after sintering the pellets at 1400°C. From the X-ray diffractometer patterns, it is evident that the zirconia exists only in the monoclinic phase. However, Rietveld refinement of calcium-doped zirconia revealed the stabilisation in the monoclinic and cubic phases. With increasing calcium doping, the development of the cubic phase in zirconia is seen and at 16 mol-% doping of calcium, almost fully stabilised cubic phase of zirconia (∼97%) is achieved. The microstructure and elemental analyses of the sintered pellets are done using a field-emission scanning electron microscopy and energy-dispersive spectroscopy, respectively. Raman spectroscopic studies validate the findings of XRD. It is expected that the present study on calcium-doped zirconia opened a new channel for its potential applications in new technology such as oxygen sensors and solid electrolyte.

In this work, the target of zirconia with 2-inch diameter is prepared from the powder form having a particle size 5 µm by giving 4 tonnes of pressure in the hydraulic press. The prepared target is sintered at 1000-degree Celsius for 10 hrs. Yttria-stabilized zirconia target is also obtained in a similar process. The structural properties of both targets are investigated using Ɵ-2Ɵ geometry of X-ray diffractometer system. The changes in structure are studied in doped and undoped zirconia. The structural findings are showing the transformation of phase with doping. These studies help to understand the structural properties of zirconia with and without doping for technological application.