The effect of temperature and pressure on Ag-Sn-Hg alloys.

Studies have been conducted to evaluate the influence of temperature and pressure on Hg loss and structural transitions in Ag-Sn-Hg alloys containing varying amounts of Sn. Hg loss and structural transitions in the alloys that were subjected to heat (100°C) and pressure (193 MN/m2) show that Sn atoms from the γz (Sn7–8Hg) phase can be forced into and accommodated by the γ1 (AgzHg3) and β1 (AgHg) lattices, leaving no γ2 as a unique phase in the alloy. Samples heated to 100°C at atmospheric pressure exhibited virtually no Hg loss for the Sn-containing alloys. However, in the absence of applied pressure, the γ1 amalgam was seen to transform to the β1 and γZ phases. This implies that Hg liberated by γ1 decomposition is not given off by the sample as free Hg but reacts with excess Ag3 to force a self-perpetuating reaction.