Spin Coated YSZ Thin Films on Silicon Substrate
Yttria Stabilized Zirconia (YSZ) thin films (<10 μm) were fabricated by spin coating technique on silicon (Si). Parameters such as concentration ratio of YSZ powder to solvent were varied accordingly. The effects of these variations were investigated and discussed. Using X-ray Diffraction and Raman Spectroscopy, the crystal structure of the samples were determined. The 8-YSZ thin films have cubic fluorite structure. The X- ray diffraction patterns were in agreement with the samples' Raman spectra. Pores were evident on single coated substrates but were minimized using higher YSZ concentration. Index Terms—Yttria Stabilized Zirconia,YSZ, spin-coating, thin film ——————————  ——————————
Processing of YSZ thin films on dense and porous substrates
Abstract Yttria-stabilized zirconia (YSZ) thin films with a Zr/Y molar ratio of 0.84:0.16 were synthesized on both dense Si substrates and porous Ni–YSZ anodes using the spin coating technique. Two polymeric precursors were used to process the YSZ films on the Si substrates. The first one utilized a commercial precursor, with butanol added as the diluting solvent. By controlling the content of butanol in the solution, dense and crack-free YSZ films with thickness of 500 nm were obtained after 8 coating runs with a final anneal of 700 °C for 4 h. X-ray diffraction was used to monitor the crystallization process in the films during annealing, which indicated that the YSZ films started to crystallize at 300–400 °C and became fully crystalline with a cubic structure at temperature ≥ 600 °C. In the second case, a new YSZ polymeric precursor was prepared and used for coating. It was found that the viscosity of the precursor solution is critical in controlling the film quality. Relatively thick, dense YSZ films were also synthesized on porous Ni–YSZ anode substrates using a combined colloidal–polymer method.
Effects of the mineral phase and valence of vanadium on vanadium extraction from stone coal
The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 mol/L H2SO4 at 90°C for 2 h. After the sample is roasted at 900°C for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the content of V(V) increases with the rise of roasting temperature from 600 to 900°C, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000°C. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.