wherein the coating material has a concentration of {HEAD ~ the specific microstructural portion} which exceeds {TAIL ~ the required concentration}, and 
wherein the coating material has a concentration of { HEAD ~ the specific microstructural portion } which exceeds { TAIL ~ the required concentration } , and
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH