Revised phase diagram and X‐ray data of The Mn₃O₄Al₂O₃ System in air

Abstract

The phase diagram of the quasi‐binary Mn3O4Al2O3 system in air has been redetermined at temperatures from 850 to 1550°C with the help of the X‐ray powder diffraction technique including high‐temperature diffractometry. Lattice constants of manganese aluminates and the powder diffraction patterns of Mn3O4, MnAl2O4 and Mn2AlO4 are presented. The influence of specimen cooling on the cubic‐to‐tetragonal transition of MnAl spinels is demonstrated. The inversion degree of the spinal compounds is discussed.

Effect of alumina additions in YSZ on the microstructure and degradation of the LSM–YSZ interface

“…Then, upon further cooling the cubic αMn 2 O 3 should form. In the present study only the hausmanite structure is [19].…”

“…The characteristic needle-like structure can be seen, which are interchangeably rich in either manganese or aluminium. This indicates that on cooling the excess aluminium, that cannot be incorporated into the hausmanite structure, precipitates as a second, aluminium-rich phase [19].…”

“…3). The tetragonalisation on cooling is a well established phenomenon in the [19,21] and is attributed to the cooperative JahnTeller effect, which is exhibited by the octahedrally co-ordinated Mn 3+ ions. The tetragonal (Mn,Al) 3 O 4 structure can only incorporate 10-15 at.…”

“…From the Mn 2 O 3 -Al 2 O 3 phase diagram [19] the stable phases at 850°C would be cubic α(Mn,Al) 2 O 3 and αAl 2 O 3 . Golikov et al [22] report the dependence of the Mn-Al-O system on temperature and oxygen partial pressure.…”

Compressibility and structural stability of spinel-type MnIn2O4

“…Surprisingly, limited information is available about Mn 2 þ -M(IIIA) spinels (M(IIIA) ¼Ga 3 þ , Al 3 þ and In 3 þ ), those capable for cooperative paramagnetic and spin-liquid behavior. Among these spinels, MnAl 2 O 4 is the most studied one [17][18][19][20][21], for MnGa 2 O 4 a number of controversial results are reported [22][23][24][25][26] and the properties of MnIn 2 O 4 are addressed in only one study [27].…”