Phase Relations and Structures in the System PbO–Fe₂O₃

Abstract

A detailed study of the system PbO‐Fe2O3, largely by X‐ray diffraction analysis, has been made. The results indicate the existence of three intermediate phases: (1) a phase (beta) extending from PbO·5Fe2O3 to PbO·6Fe2O3, (2) a phase (gamma) extending from PbO ‐ 2Fe2O3 to PbO ‐21/2Fe2O3, and (3) a phase (delta) 2PbO·– Fe2O3. Structures are proposed for the beta and gamma phases that explain their solubility limits, magnetic properties, and very great similarity in structure and in lattice dimensions.

Lead Zirconate Titanate–Magnetoplumbite Composites: A First Step Toward Multiferroic Ceramics?

“…According to the PbO–Fe 2 O 3 phase diagram depicted in Fig. 2, 16 the formation of PF (γ‐phase) occurs between 750° and 946°C, when the mol PbO/Fe 2 O 3 ratio covers the range from 1:2 to 2:5, while the formation of MP (β‐phase) starts above 760°C, with a PbO/Fe 2 O 3 mol ratio ranging between 1:5 and 1:6. Because the calcination temperature was 850°C and because of the corresponding composition, the phase stability falls in the β‐γ two‐phase region of the phase diagram.…”

“…The β–phase is a permanent magnet and has the magnetoplumbite (MP) crystal structure with the space group P 6 3 / mmc and lattice parameters of a =5.88 Å and c =23.02 Å. The unit cell contains two formula units and the structure is composed of spinel blocks with in‐between intermediate layers, each of which contains one Pb 2+ ion, three Fe 3+ ions, and three O 2− ions 16,17 …”

“…The γ‐phase is a derivative of the β‐phase structure type; it is antiferromagnetic and has the plumboferrite (PF) structure, also with the space group P 6 3 / mmc , but with cell dimensions of a =5.93 Å and c =23.55 Å. The hexagonal unit cell contains five formula units of PbO·2Fe 2 O 3 and contains layers of spinel blocks with in‐between layers hosting Pb 2+ ions, one Fe 3+ ion, and O 2− ions 16–19 …”

“…The δ‐phase is quite unexplored, with the only available data from the work of Mountvala et al 16 2PbO·Fe 2 O 3 has a nonmagnetic, tetragonal structure with lattice parameters of a =7.79 Å and c =15.85 Å, while the unit cell contains eight formula units.…”

Effect of Slag Composition on the Distribution Behavior of Pb between FetO-SiO2 (-CaO, Al2O3) Slag and Molten Copper

“…This is thermodynamically consistent with the fact that there are several stable lead ferrite compounds such as Pb 2 Fe 2 O 5 (2:1, d-phase), PbFe 4 O 7 (1:2, c-phase), and PbFe 12 O 19 (1:6, b-phase). [28,29] C. Influence of Cu 2 O on the Distribution Ratio of Pb and Stability of PbO in the Slag Phase…”