Method for preparing lanthanum zirconate powder

Abstract

The invention relates to a method for preparing a lanthanum zirconic acid powder, which belongs to the preparation field of ceramic powder used for high temperature heat barrier. The method uses lanthanum oxide or lanthanum soluble salt and zircon salt for respectively preparing the solutions containing La<3+> and Zr<4+>; the two solutions are mixed and dropped into a precipitator (or the precipitator is dropped into the mixing solutions) under continual stirring to obtain precipitate; and the precipitate are washed with a plurality of times, then dried, ground and finally calcined at certain temperature to obtain La2Zr2O7 of defect fluorite structure or pyrochlore constitution. Compared with the existing universal solid reaction process, the method lowers the synthesis temperature by 500-700 DEG C. The heat-insulating property (heat diffusivity) of the obtained power is reduced by about 50 percent compared with YSZ, and reduced by about 40 percent compared with the lanthanum zirconic acid powder obtained by the solid reaction process. The method solves the problems of overhigh heat diffusivity, severe sinter and phase change inefficiency in the existing ceramic materials used for the coating of high temperature heat barrier.

Description

technical field [0001] The invention relates to a method for preparing lanthanum zirconate powder, which belongs to the field of preparation of ceramic powder for high-temperature thermal barriers. Background technique [0002] In order to improve the thrust-to-weight ratio of aero-engines and the thermal efficiency of large gas turbines, the most feasible and economical way is to use thermal barrier coatings (TBC) on the premise of using superalloy materials and cooling technologies. As a result, the transfer of heat in the combustion chamber from the gas to the metal matrix can be reduced, the efficiency of gas use can be improved, and the oxidation of the matrix alloy can be prevented, thereby ensuring the normal operation of these hot end components at relatively high temperatures. For the selection of thermal barrier coating materials, the following conditions usually need to be met: 1) High melting point (T m >2000K); 2) Low thermal conductivity (κ<2W / m K); 3) N...

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Problems solved by technology

Although the thermal conductivity of the LZ powder obtained by the solid-state method is lower than that of YSZ to a certain extent after being pressed into tablets, its performance at higher temperatures is limited due to the large grain size and uneven particle size distribution. use

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