The bead may optionally be converted to {HEAD ~ a phosphate} or other desired phase by hydrothermal treatment after {TAIL ~ gelation} and prior to sintering 
The bead may optionally be converted to { HEAD ~ a phosphate } or other desired phase by hydrothermal treatment after { TAIL ~ gelation } and prior to sintering
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH