Study on the Phase Equilibria of the Fe-Al-Ni-O System at 750°C

Phase equilibria of the Fe-Al-Ni-O system at 750°C were determined by scanning electron microscopy coupled with energy-dispersive X-ray spectrometer and X-ray power diffraction. 54 alloys were prepared with weighted metal and Ni2O3 powder and were annealed at 750°C for 45 days. Two four-phase equilibrium regions and three three-phase equilibrium regions were confirmed, and the boundary between spinel and corundum was obtained. Comparing with the Fe-Al-Ni-O oxidation diagram at 750°C calculated with FSstel and FToxid databases, the phase boundary of the spinel and corundum oxides from experiments was inclined to the Ni-Al side. The determined relationship between primary oxides and alloy composition in this work can be used as a reference for the preparation of the oxide film by selective oxidation.

Phase Equilibrium and Synthesis in Ionic Melts of the System Na2WO4-K2WO4-Pb2WO4

Interest in a comprehensive study of lead tungstate single crystals is due to its scintillation properties [1-5]. It was found that lead tungstate occupies an exceptional position in the family of tungstates with a scheelite structure. Lead tungstate single crystal is a scintillation material [1] used in the LHC electromagnetic calorimeter and photon detector in the ALICE experiment at CERN [1, 2]. Now it can be said unequivocally that lead tungstate is the most promising scintillation material in the next decade.

Phase equilibrium diagram of the Hf-Fe-Sn system at 1070 K

Experimental studies of the phase equilibrium diagram of the Hf-Fe-Sn ternary system at 1070 K were performed by X-ray powder diffractometry, scanning electron microscopy and electron probe microanalysis techniques in the whole concentration range. At annealing temperature four ternary compounds are realized: Hf6FeSn2 (K2UF6 structure type, space group P-62m), Hf1.8Fe5Sn3.8 (Hf1.82Fe5Sn3.82 structure type, space group Cmmm), Hf3Fe4Sn4 (Zr3Fe4Sn4 structure type, space group Pnma), and Hf9Fe3.7Sn10.3 (Hf9Fe4Sn10 structure type, space group Cmc21). An existence of the Hf1-xFe2+x-ySny solid solution formed by substitution of the iron atoms by tin in the Hf1-xFe2+x (MgZn2-type) binary compound up to 19 at. % Sn was found. Solubility of Fe in the Hf5Sn3 binary (Mn5Si3-type) extends up to 10 at. % (a=0.8363(2)-0.8324(4), c=0.5726(1)-0.5686(4) nm).