Combined effects of Pb and Sn additions on the corrosion of Zn-12 pct am pct Cu-0.02 pct Mg sand cast alloy in wet steam

The effects of varying the Sn content from 0 to 0.01 pct at 0.005 and 0.015 pct Pb on the corrosion of sand-cast Zn-12 pct Al-1 pct Cu-0.02 pct Mg alloy in saturated water vapour at 95°C were investigated. Within the relevant specification limits there was no interaction between Pb and Sn, the combined effect being equivalent to that of Sn alone. The tolerance of the alloy for Sn was so low that the maximum for this impurity was considered to be 0.001 pct. For Pb, 0.01 pct produced substantially the same corrosive attack as 0.001 pct and would be considered as the upper limit for this alloy.