Liquidus Curves and Corrosion of Fe, Ti, Zr, and Cu in Liquid Bi-Pb Alloys Available to Purchase

Liquidus curves were measured of Fe in Pb, Fe in Pb-Bi alloys ranging from 39.3 to 93.5% Bi, Cu in Pb-Bi alloys around the eutectic composition, and Ti and Zr in Pb-Bi alloys of approximately the eutectic composition. In all cases these solutes are less soluble in Pb or Pb-Bi alloys than in Bi. The Fe solubility decreases monotonically with increasing Pb concentration; the logarithm of the Fe solubility is approximately a linear function of the Pb concentration with slight positive deviations, expeeially in Bi-rich alloys. The relative corrosion behavior of steels in Bi-Pb alloys at 650 to 500 C AT is estimated from the measured solubilities, and compared with the corrosion behavior of steels in these two liquids. Although the solubilities of Ti and Zr in Bi-Pb alloys are lower than in Bi, adequate amounts of these metals can be added to inhibit corrosion of steels in Pb-Bi systems and possibly also in liquid Pb systems. The heats of solution of Fe in Bi, Pb, and their alloys also increase monotonically from Bi to Pb. This behavior is interpreted in terms of the Alcock-Richardson model for dilute ternary solutions.