Transmission electron microscopic study of early stage γ1 (Ag2Hg3) and β1 (Ag-Hg) phases: Technical note

Incomplete reaction, residual free mercury, and high volatility of mercury are often major causes of the discrepancy in chemical composition of γ1 measured by different methods. The high mercury volatility also proves to be a major difficulty in transmission electron microscopy (TEM) study of high mercury materials. Provided in this report is a preparation method for TEM thin foils that can largely eliminate the mercury loss problem. The results show that the lattice constant of early stage γ1 crystals is 10.05 Δ with a chemical composition of Ag41.08Hg58.92 (or Ag2Hg2.87). The chemical composition data shows that little or no mercury is lost during specimen preparation. The lattice parameters, a and c, of β1 crystals are 3.01 and 4.88 Δ, respectively with a chemical composition of Ag1.1Hg0.94. It seems that the present specimen preparation method allows for accurate TEM microanalysis of high mercury amalgam phases such as γ1 and β1, which has been extremely difficult to do in the past.