Copper reduces gamma-2 formation in amalgam. Which metal reduces gamma-2 formation?

Copper reduces gamma-2 formation in amalgam. Which metal reduces gamma-2 formation?

• A. Zinc
• B. Copper
• C. Silver
• D. Mercury

Answer: (B)

Copper lowers gamma-2 formation because gamma-2 is the tin-mercury phase that weakens amalgam properties. When copper is present in a high-copper alloy, it binds mercury to form copper-mercury compounds, which uses up mercury that would otherwise react with tin to form gamma-2. With less free mercury available, the Sn-Hg gamma-2 phase forms far less, improving strength and corrosion resistance. The other metals don’t produce this specific effect to suppress gamma-2 in the same way.

Copper lowers gamma-2 formation because gamma-2 is the tin-mercury phase that weakens amalgam properties. When copper is present in a high-copper alloy, it binds mercury to form copper-mercury compounds, which uses up mercury that would otherwise react with tin to form gamma-2. With less free mercury available, the Sn-Hg gamma-2 phase forms far less, improving strength and corrosion resistance. The other metals don’t produce this specific effect to suppress gamma-2 in the same way.