Subsolidus area of the system CdO - V2O5 - Fe2O3

Phase diagrams in the subsolidus area of the systems FeVO₄ - CdO and FeVO₄ - Cd₂V₂O₇ have been deduced using the results of XRD and DTA analyses. On the basis of these diagrams and some additional verifying research, a projection of the subsolidus area of the CdO - V₂O₅ - Fe₂O₃ system onto the plane that comprises the components’ concentration triangle has been presented. The H-type phase is the only phase formed in this system. It co-exists at equilibrium with other phases in six subsidiary subsystems.      

Phases in the subsolidus area of the system CuO–V2O5–Fe2O3

The phase equilibria in the solid state in the system FeVO₄?CCu₃V₂O₈ and FeVO₄?CCuO have been determined. Based on the obtained DTA and XRD analysis results and some additional research, a phase diagram in the whole subsolidus area of the system CuO?CV₂O₅?CFe₂O₃ has been worked out. Eighteen subsidiary subsystems can be distinguished in this ternary system. Basic properties of the obtained phases with howardevansite- and lyonsite-type structure have been investigated by DTA, IR, and SEM methods.     

Phase relations in the system ZnV2O6 -ZnFe2O4

Using DTA and XRD methods, a diagram of phase equilibria in ZnV₂O₆-ZnFe₂O₄ system has been constructed. System ZnV₂O₆-ZnFe₂O₄ is in subsolidus area a real binary system and its components form a compound Zn₂FeV₃O₁₁. Zn₂FeV₃O₁₁ melts incongruently at 835±5°C with deposition of two solid phases: b-Zn₂V₂O₇ and ZnFe₂O₄. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reactivity of FeVO4 towards Zn2V2O7

The reactivity of iron(III) orthovanadate(V) towards zinc divanadate(V) in the solid state was investigated over the whole component concentration range. On the base of DTA and XRD measurements the phase diagram of the FeVO₄-Zn₂V₂O₇ system in the subsolidus area was constructed for the whole component concentration range. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase equilibria up to the solidus line in the V2O5−Cr2(MoO4)3 system

Phase equilibria being established in the subsolidus area of the V₂O₅?Cr₂(MoO₄)₃ system at the whole component concentration range have been studied basing on DTA and X-ray phase powder diffraction. It has been established that the system is not a real two-component system in the subsolidus area. The fact has been proved by the presence of fields in that area, where three solid phases remain in mutual equilibrium.     

Phase relations in subsolidus area of ZnO-V2O5-Fe2O3 system

Phase equilibria in subsolidus area in the ZnO-V₂O₅-Fe₂O₃ system have been investigated over the whole concentration range of the oxides. The components of this system form two compounds: Zn₂FeV₃O₁₁ and Zn₃Fe₄(VO₄)₆. A solidus area projection onto the component concentration triangle plane of the ZnO-V₂O₅-Fe₂O₃ system has been constructed using DTA and XRD methods. 11 subsidiary subsystems can be distinguished in this system. Melting temperatures of mixtures of solid phases coexisting at equilibrium in each of subsidiary subsystems were determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase equilibria up to the solidus line in the V2O5-CrVMoO7 system

The phase equilibria being established in the V₂O₅-CrVMoO₇ system in the solid state and the whole component concentration range have been studied by the X-ray powder diffraction and thermal analysis methods. The measurements have shown that the V₂O₅-CrVMoO₇ system is not a real two-component system in the subsolidus area.

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Zusammenfassung Mittels Thermoanalyse und Debye-Scherrer-Verfahren wurde das Phasengleichgewicht im Feststoffsystem V₂O₅-CrVMoO₇ im gesamten Konzentrationsbereich untersucht. Die Messungen zeigen, daß es sich bei dem System V₂O₅-CrMoO₇ im Bereich unter Solidus um kein echtes Zweikomponentensystem handelt.

     

The subsolidus area of CoO–In2O3–V2O5 system

The subsolidus phase relations of the ternary system CoO?CIn₂O₃?CV₂O₅ were investigated by differential thermal analysis and X-ray diffraction techniques. It has been shown that the system consists of seven subsidiary systems in which three solid phases coexist in equilibrium. The melting temperatures of these subsystems have also been determined.     

Phase formation in the FeVO<Subscript>4</Subscript>–Co<Subscript>3</Subscript>V<Subscript>2</Subscript>O<Subscript>8</Subscript> system

Phase relations in the solid state in the FeVO₄–Co₃V₂O₈ system, in the whole range of components concentration have been studied. It was found that the composition of the phase of the howardevansite type structure, formed in the investigated system, corresponds with the Co_2.616Fe_4.256V₆O₂₄ formula. The phase of the lyonsite type structure has a homogeneity range with the Co_3+1.5xFe_4–xV₆O₂₄ formula (0.476 formula (0.476<x<1.667). The melting temperature and the volume of the unit cell of the lyonsite type structure phase increases together with the rise of cobalt quantity contained in it. Basing on the results of the DTA and XRD measurements a phase diagram of the FeVO_4–Co₃V₂O₈ system up to the solidus line was constructed.     

Phase equilibria and solid solution relationships in the La2O3-TiO2-ZrO2 system

In the ternary La₂O₃-TiO₂-ZrO₂ system the subsolidus phase relations at 1350 °C were determined using X-ray diffraction, scanning electron microscopy end energy dispersive X-ray analysis. The collected results are presented in the form of a phase diagram. In the equilibrium state there are 7 ternary and 5 binary compatible subsystems. In the system TiO₂ss, ZrO₂ss, ZrTiO₄ss, La₂Zr₂O₇ss and La₂O₃ss solid solutions were confirmed and La₄Ti₉O₂ss and La₂Ti₂O₇ss solid solutions were identified. The addition of ZrO₂ does not stabilize the La_2/3TiO₃ perovskite compound, nor the addition of TiO₂ a highly temperature stable compound La_2/3ZrO₃.     

Phase equilibria in the Li2O-CdO-B2O3 system

Phase equilibria in the Li₂O-CdO-B₂O₃ ternary system were studied by X-ray powder diffraction analysis. Quasi-binary sections of the system were identified by the method of intersecting sections. An isothermal section in the subsolidus region at 650°C was constructed. The formation of one ternary phase, LiCdBO₃, was confirmed, which melts incongruently at 862°C.     

Phase equilibria in the solid state in the V9Mo6O40-Cr2O3 system

Phase equilibria have been established in the solid state in the V₉Mo₆O₄₀-Cr₂O₃ system. The results obtained have permitted to state that the system of interest, in the subsolidus area, is not a real two-component system in the whole component concentration range.

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Zusammenfassung Im Festzustand des Systemes V₉Mo₆O₄₀-Cr₂O₃ wurden Phasengleichgewichte ermittelt. Die erhaltenen Resultate lassen darauf schließen, daß das fragliche System im Subsolidus-Gebiet über den gesamten Konzentrationsbereich kein reelles Zweikomponentensystem ist.

     

Reaction Mechanism of Fe8W10W16O85 Synthesis

The reaction mechanism of the synthesis of Fe₈V₁₀W₁₆O₈₅ was studied by means of XRD, IR spectroscopy and DTA techniques. It was found that the intermediate in the reaction may be either FeVO₄ or FeVO₄ admixed with an unidentified phase X, depending on the reaction temperature. The IR spectrum of the phase Fe₈V₁₀W₁₆O₈₅ is reported for the first time. This revised version was published online in July 2006 with corrections to the Cover Date.     

Phase equilibria in the system FeVO4−Fe2WO6 in the solid state

A diagram of the phase equilibria established in the solid state in the system FeVO₄?Fe₂WO₆ was plotted on the basis of X-ray phase analysis and DTA. This system, one of the intersections of the three-component system Fe₂O₃?V₂O₅?WO₃, does not appear to be a real two-component system in the solid state.     

Subsolidus phase equilibria in the SrO-Bi2O3-B2O3 system

Phase equilibria in the SrO-Bi₂O₃-B₂O₃ system were studied using powder X-ray diffraction (XRD) and differential thermal analysis (DTA). Quasi-binary sections were determined, and an isothermal section of the system in the subsolidus region at 600°C was constructed using the crossing spections method. A new ternary compound was found: SrBi₂B₄O₁₀. The existence of SrBi₂B₂O₇ was verified. Bi₂O₃-SrB₂O₄ and Bi₄B₂O₉-2SrO: 3B₂O₃ polytherms were constructed.     

Subsolidus equilibria in the system BaO.TiO2.Al2O3

The subsolidus phase equilibrium relations in the system BaO.TiO₂.Al₂O₃ have been investigated using conventional solid state reaction techniques and X-ray powder diffraction. The existence of three known ternary compounds, BaTi₅Al₂O₁₄, BaTiAl₆O₁₂, and Ba₃TiAl₁₀O₂₀, was confirmed and their stability relations were studied. Various tie-lines existing between the ternary compounds and the binary titanates and aluminates of barium were established and a subsolidus phase diagram showing the phase assemblages compatible at 1200°C is presented.     

Phase equilibria in the BaO-Bi2O3-B2O3 system

Phase equilibria in the BaO-Bi₂O₃-B₂O₃ system have been investigated by X-ray powder diffraction analysis and DTA. Quasi-binary sections have been determined, and an isothermal section of the system in the subsolidus region has been constructed. The BaO-Bi₂O₃-B₂O₃ ternary system has been divided into 22 triangles of coexisting phases. It has been found that four bismuth barium borates exist, namely, Ba₃BiB₃O₉, BaBi₂B₄O₁₀, BaBiB₁₁O₁₉, and BaBiBO₄. Ba₃BiB₃O₉ undergoes a phase transition at 850°C and exists up to 885°C, where it decomposes in the solid state. BaBiB₁₁O₁₉ and BaBi₂B₄O₁₀ melt congruently at 807 and 730°C, respectively. BaBiBO₄ melts incongruently at 780°C. X-ray powder diffraction data for the low-temperature polymorph of Ba₃BiB₃O₉ are presented.     

Phase relations in the CoO–V<Subscript>2</Subscript>O<Subscript>5</Subscript>–Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> system in subsolidus area

Thermal properties of Co₂FeV₃O₁₁ have been reinvestigated. It has been proved that this compound does not exhibit polymorphism. It melts incongruently at the temperature of 770±5°C and the phase with lyonsite type structure is the solid product of this melting. Phase relations in the whole subsolidus area of the CoO–V₂O₅–Fe₂O₃ system have been determined. The solidus area projection onto the component concentration triangle plane of this system has been constructed using the DTA and XRD methods. 15 subsidiary subsystems can be distinguished in this system.     

New phase in the system FeVO<Subscript>4</Subscript>-Cd<Subscript>4</Subscript>V<Subscript>2</Subscript>O<Subscript>9</Subscript>

A new phase Cd₄Fe_7+xV_9+xO_37+4x, where −0.5<x<1.5, has been obtained in the solid-state in the FeVO₄−Cd₄V₂O₉ system. The temperature of incongruent melting and the unit cell volume of this phase decrease with decreasing the content of cadmium. The IR spectrum and SEM image of the new phase are presented.     

The FeVO4-MoO3 system

A phase diagram of the FeVO₄-MoO₃ system has been constructed from the results of DTA and X-ray analysis. The components of the system form a compound FeVMoO₇. This compound melts incongruently at 680±5 °C, with separation of the solid Fe₄V₂Mo₃O₂₀.