The fibrous carbon material is then impregnated with a second thermosetting resin containing {TAIL ~ a boron compound} and, optionally, a refractory metal capable of reacting with boron to form {HEAD ~ a metal boride} 
The fibrous carbon material is then impregnated with a second thermosetting resin containing { TAIL ~ a boron compound } and , optionally , a refractory metal capable of reacting with boron to form { HEAD ~ a metal boride }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD