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In recent years, niobium, tantalum salt series of ceramic materials by the widespread concern of the researchers, their excellent piezoelectric, ferroelectric properties, nonlinear optical effect of the crystal electro-optic effect and light refraction effect, making it the piezoelectric and thermal interpretation of electrical parts, the laser frequency doubling electro-optic modulators, optical memory and optical computing has potential applications. In these compounds, niobium, tantalum, zinc ceramic materials with excellent properties, and thus become one of the most active area of ??research in recent years, functional ceramics. ZnTa2O6 ceramic microwave dielectric properties: Q × f = 65200 GHz, er = 37.6 and τf = 9 ppm / ° C. The ZnNb2O6 with excellent microwave dielectric properties: Q × f = 87300 GHz, er = 25 and τf = -56 ppm / ° C. Molten salt synthesis of ZnTa2O6 equipment and ZnNb2O6-Hydrothermal Preparation Techniques, not yet reported in the literature, and has a leading position in the academic research in this article. In this paper, the molten salt the legal system ZnTa2O6 the powder, hydrothermal synthesis prepared ZnNb2O6 powder. Discusses in detail the procedure and conditions of the type of process methods for preparing powders to study the impact of the process conditions during the preparation of the product powder. The use of XRD, SEM, TEM, HRTEM, EDS and other means of product phase and morphology were characterized. The molten salt the synthesis of ZnTa2O6 powder, prepared by changing the molten salt system out ZnTa2O6 powder, and on the basis of this molten salt system by changing the synthesis temperature molten salt molar ratio of zinc source to study the the ZnTa2O6 product powder phase composition and morphology of the body. The results show that: (1) different molten salt system KCl-NaCl, KCl-NaCl-ZnCl2 and KCl-ZnCl2 system of experimental products. Concluded that KCl-ZnCl2 molten salt system is the most suitable for this article molten salt. Using KCl-ZnCl2 molten salt system, to analytically pure Ta2O5 and Zn (NO3) 2.6 H2O as raw materials, through the molten salt method in the temperature range of 700 ° C -800 ° C synthesized ZnTa2O6 of powder. (2) on the basis of the KCl-ZnCl2 molten salt system, by changing the reaction temperature, the molar ratio of the molten salt, zinc source to study the optimal process conditions preparing ZnTa2O6 powder. The optimal synthesis process in this article: KCl-ZnCl2 molten salt system, KCl/ZnCl2 molar ratio ≤ 0.1:1 synthesis temperature of 700 ° C insulation 3h. Compared to ZnO and Zn (OH) 2, Zn (NO3) 2 zinc raw material suitable herein. This process conditions on the basis of the successful preparation of irregular shape, an average particle size of about 700nm ZnTa2O6 powder. Using the hydrothermal synthesis prepared ZnNb2O6 powder, including hydrothermal system and solvothermal system. Discusses the process of hydrothermal and solvothermal process temperature, reaction time and the kind of solvent, pH value, presence or absence of mineralized and mineralized agent types of synthetic powders, powder particle size and shape of impact by XRD SEM, TEM, HRTEM, EDS, etc. The resulting powder phase analysis, the microstructure morphology analysis, as well as elemental composition analysis, discover the optimum conditions of preparation out ZnNb2O6 powder. The results showed that: (1) hydrothermal system has many advantages, but in this article by hydrothermal system through a variety of process conditions, including changes in raw materials, pH, mineralizing agent types are still unable to succeed in the water as reaction The solvent conditions prepared out ZnNb2O6 powder. (2) in the solvent under heat system using cyclohexane as a solvent, it is possible to successfully synthetic ZnNb2O6 powder, the particle size in the 50 nm to about 200nm. (3) Study of the solvothermal conditions, kind of solvent, kind of mineralizing agent, reaction temperature, reaction time on product. I.e. cyclohexane compared to ethylene diamine, tetra-methyl ammonium hydroxide is a suitable solvent: Comparison with different mineralizing agent, without mineralizing agent, the use of the solvothermal method can be successfully prepared ZnNb2O6 powder; 190 ℃ and above temperature can the success ZnNb2O6 crystal phase, while above 190 ℃ temperature increase had no significant effect on the Crystallinity: reaction time on the the crystal powder ZnNb2O6 product growth and no obvious effect on the morphology, thereby extending holding time on of this article ZnNb2O6 crystalline phase generated no positive impact. Niobium pentoxide and zinc nitrate as raw materials, solvent cyclohexane as a mineralizing agent is not added, solvothermal reaction temperature of 190 ° C and at different times (10 min-6h) can successfully prepared ZnNb2O6 powder. Grains having a fine crystal structure and a wide particle size distribution range. Primary particles, crystal morphology is complete, the the first grain particle size of about 50nm-200nm, wherein the large particles is considered to be a small-particle aggregates.
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