Specimens of a gallium-based dental alloy were prepared with different condensation techniques, with and without the removal of a surface layer, and after aging for 2 hours at 50°, 100° and 150°C. X-ray diffraction at times ranging from 10 minutes to 1 day showed the development of the four matrix phases (ß-Sn, CuGa2, Ga28Ag72, and In4Ag9) during the setting reaction. Scanning electron microscope (SEM) examination of specimens loaded to failure revealed brittle fracture, with greater porosity for hand-condensed specimens, and provided insight into crack propagation processes. Aging increased the amount of ß-Sn in freshly prepared specimens, and removal of the Ga-rich surface layer after condensation decreased the amount of this phase. For specimens stored for 5 weeks at room temperature, aging substantially increased the amount of the CuGa2 phase but caused only moderate increases in the amount of ß-Sn.
Shaker, Randa E.; Brantley, William A.; Wu, Qiang; and Mitchell, John C.
"X-Ray Diffraction and Scanning Electron Microscopy Analyses of a Gallium-Based Dental Restorative Alloy,"
Cells and Materials: Vol. 9
, Article 5.
Available at: http://digitalcommons.usu.edu/cellsandmaterials/vol9/iss1/5