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