Thermal stability of nanostructurally stabilized zirconium oxide

Abstract

Nanostructurally stabilized zirconium oxide (NSZ) hard transparent films were produced without chemical stabilizers by the ion beam assisted deposition technique (IBAD). A transmission electron microscopy study of the samples produced below 150 °C revealed that these films are composed of zirconium oxide (ZrO2) nanocrystallites of diameters 7.5 ± 2.3 nm. X-ray and selected-area electron diffraction studies suggested that the as-deposited films are consistent with cubic phase ZrO2. Rutherford backscattering spectroscopy (RBS) indicated the formation of stoichiometric ZrO2. The phase identity of these optically transparent NSZ films was in agreement with cubic ZrO2, as indicated by the matching elastic modulus values from the calculated results for pure cubic zirconium oxide and results of nanoindentation measurements. Upon annealing in air for 1 h, these NSZ films were found to retain most of their room temperature deposited cubic phase x-ray diffraction signature up to 850 °C. Size effect and vacancy stabilization mechanisms and the IBAD technique are discussed to explain the present results.

Ambient temperature stabilization of crystalline zirconia thin films deposited by direct current magnetron sputtering

“…It should be noted that the films at low O 2 ratio would have significant oxygen nonstoichiometry creating oxygen vacancies. The correlation between strain, grain size, vacancies and formation of the cubic phase at ambient temperature has been reported previously [27] and the grain size dependent low temperature formation of cubic phase is well documented [28]. There are also a few reports that correlate the stability of the cubic phase with strain [29,30].…”

Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

“…7. 31 Remarkably, as shown in Fig. 8(b), the growth exponent b remains approximately constant across the whole temperature range (varying between 0.380 and 0.406).…”

“…[31][32][33][34] These approaches concentrate on the Author to whom correspondence should be addressed. Electronic mail: pmilani@mi.infn.it crystalline structure and thermal stability of the films; no systematic investigation on the nanoscale structure and topography and on their reproducibility, thermal stability and quantitative control have been reported so far.…”

Bulk modulus for polar covalent crystals

“…2 are systematically smaller than experimental values1317224243. It should be noted that an average bond length was used for rutile and corundum structures in Table 2.…”