The substrate consists of a metal or {HEAD ~ an alloy} mainly composed of Ni or Al, or {TAIL ~ stainless steel} 
The substrate consists of a metal or { HEAD ~ an alloy } mainly composed of Ni or Al , or { TAIL ~ stainless steel }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL