A powder core 1 wherein said upper layer coating has an average thickness of {HEAD ~ at least 10 nm} and {TAIL ~ no more than 1 micron} 
A powder core 1 wherein said upper layer coating has an average thickness of { HEAD ~ at least 10 nm } and { TAIL ~ no more than 1 micron }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL