Ag-Sn-Hg alloys as electron compounds

✍ Scribed by Johnson, L. B.

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 283 KB
• Volume: 4
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.820040207

✦ Synopsis

The extraordinary stability of the y, phase of dental amalgam was believed to indicate that part of the Sn in dental amalgam was contained in this phase. By extending the Hume-Rothery "electron compound" ideas to the three component Ag-Sn-Hg system, an estimate was made of the amount of Sn which could be held in the y~ structure.

A Ag-Sn alloy containing 9.1 weight per cent Sn was prepared, spheroidized, and sized. Portions were amalgamated and molded into tensile specimens, parts of which were subjected to X-ray diffraction, corrosion tests, and tests t o determine amalgamation rate and dimensional changes during setting.

X-ray diffraction patterns showed a complete absence of the 7 2 phase, (thus indicating that all Sn was in the y1 phase) and a stability intermediate between y Ag-Hg and the yl phase of dental amalgam. Physical tests showed a low amalgamation rate, low 1-hr strength, high 7-day strength, and high corrosion resistance.