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