Influence of grain boundary sliding on diffusion in yttria doped zirconia

A study into stress relaxation in oxides formed on zirconium alloys

“…These tend to range from 0-8 wt% yttria or calcium, 75 nm-15 lm grain size, 950-1600°C test temperature, with the creep test stresses reaching 200 MPa. Typically, the grain size power ranges between 2 and 3, and the stress exponents range from 1 to 2, leading most authors to the conclusion that either Coble or Grain Boundary Sliding creep mechanisms are in operation [23][24][25][26][27][28]. Identification of transitions in the creep mechanisms are very rare and difficult to validate [24].…”

“…A fundamental issue with all of the creep tests, particularly with very small grain sizes, is the tendency for dynamic grain growth to occur. This has been known to generate additional strain in the materials and although attempts are frequently made to correct for this, it adds significant uncertainty to the analysis [23][24][25][26][27][28]. Another issue is the presence of the doping elements which are known to segregate to grain boundaries and have been linked with reduction in diffusion due to a solute dragging mechanism [26].…”

“…Strain rates of up to 1 Â 10 À3 s À1 have been recorded at 1150°C for nanocrystalline, yttria stabilised tetragonal zirconia [23]. This has led to a significant amount of research into creep [23][24][25][26][27][28], and a number of tracer element diffusion tests designed to define the diffusion coefficients have been conducted [29][30][31][32]. However this temperature is much higher than would be observed in reactor under normal operating conditions, and the morphology of the oxides are very different.…”

Performance enhancement of natural pigments on a high light transmission ZrO2nanoparticle layer in a water-based dye-sensitized solar cell

“…However, the coating materials that are applied in optics must be stable and have certain optical properties, such as a high refractive index. ZrO 2 is a green material [5][6][7] with a very low thermal conductivity [8,9] and high refractive index (n = 2.3-2.1 in visible light regime) [10], and is able to act as an insulator for buildings. If the transmission of light were controlled to exhibit high transmission in winter and high reflectance in summer, the building would be cool in summer and warm in winter, making it a so-called green building.…”