Patent ID: 7354565

Claim:
A two-step calcination process for the preparation of lead iron tungstate relaxor material comprising subjecting appropriate initial mixture of starting materials of weighed amount of a wet ground iron oxide and tungsten oxide to calcination at a temperature of about 1000Â° C. for a period of 2 hours, subjecting the calcined material to further grinding for about ten hours after mixing lead oxide therein and then subjecting the mixed calcined material again to calcination at a temperature in a range of 750 to 830Â° C. to yield a final product stoichiometric Pb(Fe 2/3 W 1/3 )O 3 , wherein excess PbO is used to obtain a self-doped stoichiometric relaxor material, and doping is done by adding excess amount of PbO salt to the initial mixture and wet grinding the mixture so obtained in order to homogenize the mixture so obtained.