Homogeneous yttria stabilised zirconia lms were synthesised using thermal annealing of Y/Zr layers of strictly controlled thickness in air in the temperature range 600 -1000°C. Intermixing and oxidation kinetics were investigated. Secondary ion mass spectrometry analysis was used to record the depth pro les of the most important elements across the thickness of the synthesised lms. The characterisation of lm structure was carried out by X-ray diffraction. Surface roughness and topography were monitored by atomic force microscopy and scanning electron microscopy. Results showed that there is a correlation between surface topography and mixing and oxidation kinetics. The existence of columnar boundaries and a nanocrystalline structure in the lms seem to affect the oxygen penetration mechanism signi cantly.

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Thin films of ZrO2-8mol%Y2O3 have been deposed by pulsed DC magnetron sputtering method. The substrates of Ni-cermet and alloy-600 for the films were used. The results of the investigation of the X-ray diffraction patterns and SEM showed that the films are nanocrystalline and belong to cubic symmetry. The relaxation process is related to the ion transport in thin films. The results of the investigation of the temperature dependencies of thin films ionic conductivity (σ) showed that the dependence σ(T) is caused by the temperature dependence of oxygen vacancy mobility, while the number of charge carriers remains constant with temperature.

This paper presents a generalized approach to the mechanisms of oxidation, hydrogenation and nitriding of metals under ion irradiation with reactive particles at elevated temperatures. Experimental results on the plasma oxidation of bilayered Y/Zr lms, the plasma hydrogenation of Mg lms and the ion beam (1.2 keV N + 2 ) nitriding of stainless steel are presented and discussed. We make special emphasis on the analysis of surface e¬ects and their role in the initiation of mixing of bilayered lms, the ingress of reactive species in the bulk and the restructuring of the surface layers. It is suggested that primary processes driving reactive atoms from the surface into the bulk are surface instabilities induced by thermal and ballistic surface atom relocations under reactive adsorption and ion irradiation, respectively. The di¬usion of adatoms and vacancies, at temperature when they become mobile, provide the means to relax the surface energy. It is recognized that the stabilizing e¬ect of surface adatom di¬usion is signi cant at temperatures below 300-350 o C. As the temperature increases, the role of surface adatom di¬usion decreases and processes in the bulk become dominant. The atoms of subsurface monolayers occupy energetically favorable sites on the surface, and result in reduced surface energy.