The phase relationships of the ternary system Eu 2 O 3 - La 2 O 3 - ZrO 2 and binary Eu 2 O 3 - La 2 O 3 subsystem were experimentally and thermodynamically studied. Six three-phase fields and nine two-phase ones in the Eu 2 O 3 - La 2 O 3 - ZrO 2 system were investigated by X-ray diffraction, scanning electron microscopy and electron probe microanalysis with wavelength dispersive spectrometer at 1873 K and 1673 K. Nevertheless, there only existed a two-phase region in the Eu 2 O 3 - La 2 O 3 system in the temperature range from 1873 K to 1673 K. After that, the ternary mixing parameters for the system Eu 2 O 3 - La 2 O 3 - ZrO 2 including the binary interaction parameters in the Eu 2 O 3 - La 2 O 3 subsystem are optimized with the CALPHAD (CALculation of PHAse Diagrams) method, based on obtained experimental results. The high-temperature phase relationships and the special type of continuous solid solutions (La 2-x Eu x Zr 2 O 7 ) investigated in present work will contribute to exploring new materials with specific properties such as optical transparency.
Growth of high-quality III–V nanowires at a low cost for optoelectronic and electronic applications is a long-term pursuit of research. Still, controlled synthesis of III–V nanowires using chemical vapor deposition method is challenge and lack theory guidance. Here, we show the growth of InP and GaP nanowires in a large area with a high density using a vacuum chemical vapor deposition method. It is revealed that high growth temperature is required to avoid oxide formation and increase the crystal purity of InP nanowires. Introduction of a small amount of Ga into the reactor leads to the formation of GaP nanowires instead of ternary InGaP nanowires. Thermodynamic calculation within the calculation of phase diagrams (CALPHAD) approach is applied to explain this novel growth phenomenon. Composition and driving force calculations of the solidification process demonstrate that only 1 at.% of Ga in the catalyst is enough to tune the nanowire formation from InP to GaP, since GaP nucleation shows a much larger driving force. The combined thermodynamic studies together with III–V nanowire growth studies provide an excellent example to guide the nanowire growth.