| Since it was reported that SrCeO3 doped Yb3+ion showed good protonic conduction under atmosphere containing hydrogen or steam at high temperature in early 1980's, the applications of perovskite-type proton conductors on electrochemical devices such as solid oxide fuel cells, gas sensors, hydrogen pump, steam electrolyzer for hydrogen production, hydrogenation and dehydrogenation of organic compound have exihibited very important values and wide prospect and attracted extensive attention all over the world.In this paper, we reviewed crystal structure, forming of proton, conduction mechanism and application prospect of perovskite-type proton conductors, and characteristics of perovskite-type proton conductors were classified and discussed according to their chemical constituents (1 st Chapter). And then the common preparation and characterization methods of perovskite-type proton conductors were introduced (2nd Chapter); The influence of milling time for original mixture during the preparation process on partical size distribution, crystal structure, micro-topography and electrical property of BaCe0.90Y0.10O3-αand Ba3Ca1.18Nb1.82O9-δpowders and sintered samples were discussed (3rd,5th Chapter); This paper attempts to form CaZr0.9In0.1O3-αtubes by hot pressure casting. And a set of reasonable process parameters were found. Meanwhile, properties of CaZr0.9In0.1O3-αproton conductor were characterized (4th Chapter). The present situation about dehydrogenation and detection of hydrogen in molten aluminium and aluminium alloy was introduced at home and abroad at present; Electrochemical hydrogen pumps constructed by CaZr0.9In0.1O3-α, BaCe0.90Y0.10O3-α, BaCe0.85Y0.15O3-αand BaCe0.90Sm0.10O3-αas electrolytes were used to dehydrogenate molten aluminium and the hydrogen content was detected by the sensors constructed by CaZr09In0.1O3-αas electrolyte by electrochemical method (6th Chapter); At the end of the paper, the discussions were summed up (7th Chapter) and further studying on perovskite-type proton conductors and its development direction was described (8th Chapter). The main research results of this work were reported as follows:(1) The powder particles were refined by prolonging the milling time of original mixture properly, which can not only lower the synthesis temperature of BaCe0.90Y0.10O3-αor Ba3Ca1.18Nb1.82O9-δ, but also can synthesize the powders with small particle size, narrow particle size distribution and large specific surface area. As a result, the densities and electrical properties of sintered samples were improved, respectively.(2) The conductivities of BaCe0.90Sm0.10O3-α,BaCe0.90Y0.10O3-αand BaCe0.85Y0.15O3-αproton conductors increased, whose activation energies decreased in turn at 573-873K in air. This result indicates that the electrical properties of BaCeO3-based materials also can be improved by means of increasing the concent of Y3+ion or doping the ion whose radius is close to the radius of Ce4+ion.(3) A set of reasonable parameters for forming CaZr0.9In0.1O3-αtubes by hot pressure casting included the casting pressure 0.5MPa, the duration of pressure 15s, the mold temperature 30℃, the wax material temperature 73℃, the wax material composed of powders 87.8%, paraffin 11%, beeswax 1%, oleic acid 0.2% and the wax removal temperature 1000℃. The content of In3+ion decreased in the sintered samples, which was due to the dissociation of In2O3 for InO and O2 during the sintering.(4) Electrochemical hydrogen pump constructed by CaZr0.9In0.1O3-αas electrolyte was used to dehydrogenate the molten Aluminium by vacuum extracting, gas carrying or applied voltage method, respectively. The results showed that the fastest dehydrogenating rate was realized by applying voltage 1.5V, and then vacuum extracting. The dehydrogenating rate by gas carrying was relatively low. The effect of oxygen gas carrying was better than that of argon gas carrying.(5) The molten Aluminium is dehydrogenated by an electrochemical hydrogen pump constructed by BaCe0.90Sm0.10O3-α, BaCe0.85Y0.15O3-αand BaCe0.90Y0.10O3-αas electrolyte in molten aluminium at 760℃,780℃and 800℃, at water vapor pressure between 4122.8Pa and 4754.7Pa and applied voltage of 0.4V,0.8V and 1.2V, respectively. The results exhibited that the current in the pumps became larger when the temperature in molten Aluminium, water vapor pressure or applied voltage increased.(6) The mixture of YH0.55+YH0.9 was synthesized as a new type of reference electrode material. The response time of the hydrogen sensor constucted by CaZr0.9In0.1O3-αas electrolyte and YH0.55+YH0.9 as reference electrode was about 20s. |
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