Y2O3 stabilizer

Figure 7.8 Zirconia-yttria binary system. The introduction of yttria into zir-conia ( — 15-51% Y2O3) stabilizes the structure into the cubic form throughout the usable temperature range of the refractory material [11],...

Aerosol-assisted chemical vapor deposition is illustrated by work published by Siadati et al. (2004). An aerosol is a vapor suspension of finely divided particles. The particles can be solid, as in smoke, or liquid, as in fog. A toluene solution of Zr(tfac)4, Y(hfac)3, and Ce(tmhd)4, converted to an aerosol, was used to deliver the metal in a carrier gas of O2. The film deposited was CeC>2-doped Y2O3-stabilized zirconia. The ligands used in this work to produce volatile metal compounds are frequently used in chemical vapor deposition. Trifluoroacety-lacetonate (tfac), hexafluoroacetylacetonate (hfac), and tetramethylheptanedionate (tmhd) are all 3-diketonates, and their structures are shown in Figure 3.22. Like the diethyl dithiocarbamates mentioned above, these precursors could potentially be the source of both the metal and the oxygen in the chemically deposited film. However, to ensure that the metal remains at its highest oxidation state and to avoid a film with mixed valencies on the metal, oxygen is used as the carrier gas. 

Solid oxide fuel cell (SOFC) uses solid ceramic material, such as Y2O3 stabilized Zr02 (YSZ), as an electrolyte. As SOFC operates at high temperature (600-1000° C), a variety of fuels, e.g., hydrogen, methane, and carbon monoxide, can directly be utilized. The high temperature places severe constraints on material selection and results in difficult fabrication process. Co-ZrO (or Ni-ZrO) and SrO doped LaMn03 have often been used for anode and cathode materials, respectively. 

The electrolyte in this fuel cell is a solid, nonporous metal oxide, usually Y2O3-stabilized Zr02. The cell operates at 1000°C where ionic conduction by oxygen ions takes place. Typically, the anode is Co-Zr02 or Ni-Zr02 cermet and the cathode is strontium-doped LaMnOs. 

The majority of EP studies have been carried out so far using 8 mol% Y2O3 -stabilized - Z1O2 (YSZ), an conductor, as the solid electrolyte (Table 1). 

Protective coatings for the hot gas duct tested were a NiCrAlY basis layer followed by a Y2O3 stabilized Zr02 layer. Other components which need to be especially designed are the isolation valves. Two different kinds have been investigated, axial-type and ball-type valves. Further tests before application are still necessary [41]. 

Electrolyte ZrOj Y2O3 stabilized Zr02 (YSZ) Basic material... 

The first implementation of such a sensor device is reported in Rbder-Roith et al. (2009), in which 8 mol% Y2O3 stabilized zirconia (YSZ) was used for the gas sensitive material. The sensor set-up was similar to the sensors described above however, an additional Pt-cermet was applied to get a high... 

This is a cell where the electrolyte is Y2O3 stabilized with Zr02, operating at 800-1000°C. SOFCs have an efficiency similar to MCFCs. The high operating temperature allows internal reforming, but suitable materials of fabrication are an issue. The CO is generated from the water gas shift reaction that occurs within the cell. 

Fig. 2.72 The influence of the temperature, T (diagrams a, c, e) at V h = 0.5 mm/min and of the speed V<-h, (diagrams b, d, f) at T = 1200 °C on the appearance of the load (P) versus deflection <5 a, b SN-1 c, d A-1 e, f Y-PSZ-3. SN-1 is a silicon nitride-based ceramic with additions of Y2O3 and AI2O3 A-1 is an alumina-based ceramic with an addition of MgO and Y-PSZ-3 is a Y2O3 stabilized zirconia based single crystal [18]. With kind permission of Elsevier...

Fig. 6.58 Typical creep experiment in Y2O3-stabilized Z1O2 at stresses of 84 and 66 MPa and three temperatures, 1466, 1516-1518, and 1558 °C [64]. With kind permission of John Wiley and Sons...

The first example concerns a composite of (SC2O3 -1- Y2O3) stabilized ZrOa, a pure ionic conductor, and LaossSro.isMnuoO, a pure electronic conductor, at a volume fraction 0.30 for the latter. Figure 4.1.48 shows an impedance spectrum obtained at ambient conditions. It resembles that of a classical solid electrolyte, with a bulk resistivity of 5 x 10 Qcm and a bulk capacitance of 4 x lO Fcm". ... 

Figure 4.148. Impedance spectrum at ambient conditions for a composite of (SC2O3 + Y2O3) stabilized Zt02, and LaossSr o.isMni.ioOi at a volume fraction 0.30. The spectrum resembles that of a classical solid electrolyte, but the bulk conductivity exceeds the expected value by a factor of 10. ...

Zirconium Oxide (Zr02) (stabilized, 0% porosity) Zirconium Oxide (Zr02) (stabilized, 0% porosity) Silicon Dioxide (Si02) Zirconium Oxide (Zr02) (Y2O3 stabilized) 0.005 at 200°C 0.005 at 400°C 0.005 at 1200°C 0.0053 at 800°C... 

The transport kinetics of Mg in cubic 10mol%Y2O3-stabilized zirconia were studied. 

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