Search

We report a fluxing technique for ZrMo 2 O 8 single crystal growth. The volatility of MoO 3 coupled with the limited temperature range of its stability with the liquid phase makes the single crystal growth of ZrMo 2 O 8 a formidable challenge. Single crystal growth of ZrMo 2 O 8 was carried out in a horizontal tubular furnace using a platinum boat and utilizing Li 2 MoO 4 as a fluxing agent. The synthesized faceted crystals were up to 3 mm along the maximum dimension. Laue and single crystal X-ray diffraction confirmed the monoclinic crystal structure having a space group C 1 2/c 1 (S.G#15), and a single crystallographic domain within the crystals. Reduced elastic modulus and hardness were determined to be 108±4 GPa and 6.4±0.2 GPa respectively using nanoindentation. Appearance of additional peaks in Raman spectra of the indented region when compared with the fresh crystal indicated a possible pressure induced phase transformation during indentation. [ABSTRACT FROM AUTHOR]

Abstract: ZrW2O8 is known for its isotropic negative thermal expansion over a wide of range of temperature from −272 to 777°C. However, ZrW2O8 melts incongruently at 1257°C and is stable only over a short temperature interval between 1105 and 1257°C. This makes the growth of single crystals a formidable challenge. In order to study the intrinsic properties of this compound, a repeatable, viable single crystal growth strategy is required. Here we report a simple, self-seeding, self-fluxing single crystal growth process which resulted in single crystals of ZrW2O8 up to about 4mm in size. Grown crystals were characterized by X-ray diffraction (XRD), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Mechanical properties of the crystals were studied using nanoindentation. [Copyright &y& Elsevier]