Aqueous ammonia was made use of to regulate the pH value of the solution at about 8.5.After ballmilling and drying,the powders were calcined in the air at 650 องศาเซลเซียส for 2 hr. Polyvinyl alcohol(PVA)was added into the remilled powders as organic binder to help the formation of cylindrical compacts of about 12 mm in diameter and 1 mm in height under a uniaxial pressure of around 20 MPa.