Na2 O is then dispersed in the calcined starting mixture to form a final mixture, and the final mixture is heated in {HEAD ~ an oxygen containing atmosphere} to above {TAIL ~ 1100° C.} to produce β alumina 
to above
Na2 O is then dispersed in the calcined starting mixture to form a final mixture , and the final mixture is heated in { HEAD ~ an oxygen containing atmosphere } to above { TAIL ~ 1100 ° C. } to produce β alumina
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH