The coins (UK Sterling) being tested are:
1 pound coin - Nickel brass (70% Cu, 5.5% Ni, 24.5%Zn)
10 pence coin - Cupro Nickel (75%Cu, 25%Ni)
2 pence coin - Copper plated steel (97% Cu, 2.5%Zn, 0.5%Sn)
15 to 16% oxygen in stomach gas so reactions could occur.
What about these alloys?