Journal of Dental Research, Vol 64, 67-73, Copyright © 1985 by International & American Associations for Dental Research Online Journals
Structural changes in the oxidation zones of gold alloys for porcelain bonding containing small amounts of Fe and Sn
H. Ohno and Y. Kanzawa
The oxidized surfaces of cross-sections of gold alloys containing a total
of 1.5 mass % Fe and Sn, oxidized at 1000 degrees C for one hr, have been
studied by various techniques, including secondary electron micro-analysis,
X-ray micro-analysis, X-ray diffraction, and thermogravimetry. Over the
composition range (0.30-1.50 mass % Fe), an external oxidation zone
containing only Fe oxides was formed. The quantity of Fe2O3 was greater
than that of SnO2 for 0.45-1.50 mass % Fe. With an Fe content below 0.45
mass %, the amount of SnO2 was greater than that of Fe2O3. Traces of Fe3O4
were formed in high Sn content alloys. Internal oxidation particles
composed of Fe2O3 and SnO2 precipitated deep in the alloy matrix (0.90-1.50
mass % Fe), and these changed to an internal oxidation band composed mainly
of SnO2 for 0.3 mass % Fe.
