Synthesis and Characterization of Nanocrystalline Hf6Ta2O17 Ternary Oxides by Solvothermal Method

Herein, nanocrystalline Hf6Ta2O17 ternary oxide powders have been newly synthesized from hafnium chloride and tantalum chloride as starting materials using the solvothermal method. As confirmed by powder x-ray diffraction analysis, single-phase Hf6Ta2O17 powders were prepared at a minimum temperature of 1200 degrees C for 1 h. The cell parameters of the Hf6Ta2O17 powders were calculated precisely by Cohen's method, confirming the superior phase stability of the samples. Moreover, as demonstrated by a combination of characterization techniques, the nanoparticles were highly crystalline and homogenously distributed with crystallite sizes of approximately 50 nm. The measured fringe spacing of the crystal lattice is in agreement with the theoretical value, and the selected area electron diffraction pattern revealed the single-crystalline nature. Finally, the synthesized powder was densified into monolithic Hf6Ta2O17 ceramics with high relative density (97.9%) by pressureless sintering.