wherein {HEAD ~ the metal} is selected from {TAIL ~ the group} consisting of: cobalt, nickel or chromium, and a metal alloy of these metals 
is selected from
wherein { HEAD ~ the metal } is selected from { TAIL ~ the group } consisting of : cobalt , nickel or chromium , and a metal alloy of these metals
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH