There is then a further heating and cooling step in a reducing atmosphere wherein {HEAD ~ the oxidised metallic component} is reduced to {TAIL ~ a metal} 
is reduced to
There is then a further heating and cooling step in a reducing atmosphere wherein { HEAD ~ the oxidised metallic component } is reduced to { TAIL ~ a metal }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL