Ammonium Paratungstate Preparing Nano-Scale Zirconium Tungstate--Hydrothermal Synthesis Method

Zirconium tungstate belongs to ceramic materials, its widest temperature range of negative effects of expansion, high negative thermal expansion and maintain isotropic, making it one of the hot negative thermal expansion material of a Subsidiary . Zero expansion or low expansion material can significantly improve the thermal stability and geometric impact resistance. In this article, nano-scale zirconium tungstate with uniform particle size and negative good expansion properties is prepared from ammonium paratungstate and zirconium oxychloride by hydrothermal synthesis method.



Steps as follows:
1. Take an appropriate amount of ammonium paratungstate and thermal decompensate under a certain conditions to obtain ammonium metatungstate;
2. Respectively take and weight the zirconium oxychloride and ammonium metatungstate according to a certain proportion, and then formulate into zirconium oxychloride and ammonium metatungstate solution;
3. Stirring the AMT solution, and adding zirconium oxychloride solution at the same time, continually stirring and preheating the solution to 60~70 ° C for I~3 hours; and then adding hydrochloric acid solution with stirring and heating to 80~100°C for 2.5~3.5 hours, then zirconium tungstate precursor suspension got;
4. Zirconium tungstate precursor suspension is carried out hydrothermal reaction at 170~190°C for 4~6 hours, and then cooled down, the precipitate was collected and washed to remove Cl^-; after dried, the precipitate is calcined at a 800~KKKTC for 1~5 hours to obtain the product we need.

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