Metastable Phases of Mgo-TiO₂ Solid Solutions

Author

Liang-Chieh Ma

Date of Award

12-2002

Degree Name

Master of Science

Department

Civil and Construction Engineering

First Advisor

Dr. Pnina Ari-Gur

Second Advisor

Dr. James W. Richardson Jr.

Third Advisor

Dr. John B. Miller

Access Setting

Masters Thesis-Open Access

Abstract

Magnesium titanium oxide powders were synthesized by the sol-gel method using alkoxides of magnesium and titanium with different ratios. Matastable phases of qandilite, Mg₂TiO₄, were found with Mg:Ti ratios down to 1.52:1 in lower temperature 600 °C than in the equilibrium condition which is above 1200 °C. Powder samples were examined by neutron powder diffraction and X-ray photoelectron spectroscopy (XPS) for analysis of structure and oxidation states. Also, samples were tested for the Mg:Ti ratios by induced coupled plasma atomic emission spectrometry. The structure refinements of the samples were done by General Structure Analysis System (GSAS) using the Rietveld refinement method. Particle sizes were calculated from structure refinement. For the X-ray photoelectron spectroscopy analysis the commercial geikielite, MgTiO₃, and qandilite, Mg₂TiO₄ which was annealed at 1180 °c were used as references when were compared with nanostructured samples. The XPS results showed that Ti cations had lower oxidation states in the metastable samples with Mg:Ti ratios 1.52:1 and 2:1 than in the sample that was created under the stable condition in order to keep charge balance for the samples.

Recommended Citation

Ma, Liang-Chieh, "Metastable Phases of Mgo-TiO₂ Solid Solutions" (2002). Masters Theses. 4334.
https://scholarworks.wmich.edu/masters_theses/4334