Zirconia calcia-stabilised

The standard Gibbs energy of formation of NiO has been experimentally determined over the temperature range from 900 to 1400 K using a galvanic cell with the solid electrolyte made of 15% calcia-stabilised zirconia. The measured value of AfG (NiO) at 1300 K was - 123.555 kJmol with a precision of+0.057 kJ-mof and an estimated accuracy not worse than 0.200 kJ-mol. This precision is equivalent to an error of only 0.2 - 0.3 mV in the cell potential (emf). In comparison, most previous studies have reported a precision of 1 - 2 mV. Using the third law analysis, the authors obtained for the enthalpy of formation of NiO, Af//° (NiO, 298.15 K) = - 240.110 kJ-mol. ... 

This is an excellent study of NiO, CoO, Ni2Si04 and Co2Si04 using an electrochemical technique. Cells were used with calcia-stabilised zirconia as an oxygen specific electrolyte. The fact that not only the overall cell reaction ... 

Thermodynamic data of high accuracy and reliability for the Ni - NiO system at high temperatures were obtained from electrochemical cells with yttria- or calcia-stabilised zirconia electrolytes. The experimental results are in excellent agreement with available calorimetric data as well as emf measurements of previous publications. The recommended Gibbs energy equation for the reaction ... 

Calcia-stabilised zirconia provides a good example of the consequences of incorporating an ion with... 

Figure 3.16 The structure of calcia stabilised zirconia. The crystal contains a number of Ca ions substituted for Zr ions. Each Ca ion is accompanied by an 0 vacancy to maintain charge neutrabty. The unit cell is outlined...

The elastic modulus of sintered calcia stabilised zirconia with a porosity of 5 % is 151.7 GPa. Estimate the elastic modulus of completely-pore-ffee material. 

Uranium dioxide has a number of properties that make it suitable for a fuel. The crystal structure is the fluorite (CaF2) type, similar to that of calcia-stabilised zirconia, and is stable to temperatures in excess of 2000 °C. Because it is a ceramic oxide, the material is refractory, chemically inert and resistant to corrosion Enrichment does not change these features. The oxide powder is pressed into pellets and sintered to a density of about 95 % maximum by traditional ceramic processing technology but is carried out in conditions that minimise risks from radiation effects. The pellets are contained in zirconium alloy (zircaloy) containers, which are then introduced into the reactor. The moderator, which... 

On the same diagram the electrolytic domains for calcia stabilised zirconia and yttria doped thoria is shown. There is a certain uncertainty on the exact limit of these domains. One can see for instance that for measurement in molten copper at say 1200 C, no problem with electronic conductivity of zirconia should be met down to an O2 partial pressure of 10 " atmosphere. On the other hand measurement in steel at I600 C appears to be limited to between 10 8 and 10 " atm. 

The tubular SOFC was pioneered by the US Westinghouse Electtic Corporation (now Siemens Westinghouse Power Corporation or SWPC) in the late 1970s. The original design used a porous calcia-stabilised zirconia support tube, 1 to 2 mm thick onto which the... 

In the late 1970s, electrochemical vapour deposition began to be used to make tubular cells at Westinghouse [9.10]. A porous tubular substrate, around 15-20 mm in diameter, made originally from calcia-stabilised zirconia but later from the cathode material, doped lanthanum manganite, was placed in a low-pressure furnace chamber, and zirconium chloride plus yttrium chloride... 

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