The objective of this work was to optimize the process of non-linear polarization (apodization) of piezoelectric ceramic disks. The apodization of the piezoelectric ceramic was performed to reduce the diffraction in the acoustic field generated by ultrasonic transducers. We looked for the better temperature of the insulating mineral oil that surrounds the piezoelectric ceramic, and how long the poling electric field should be applied to the ceramic to achieve a good apodization (piezoelectric coupling coefficient k t>0.4 for the thickness mode of vibration). We have tested different initial oil bath temperatures and time interval of the poling field application. The results showed that if we raised the oil bath temperature above 200°C we needed to apply the poling field for a shorter time. Temperatures below 160°C were efficient only when the poling field was applied until the oil were cooled down to 35°C (what did not take less than 4 hours). We concluded that using higher temperatures, but still below Curie Point, it was possible to reduce the poling process, with satisfactory results, from 4-5 hours to 5 minutes.2 11111114Button, V.L.S.N., Costa, E.T., Maia, J.M., Non-uniform piezoelectric ceramic polarisation: Minimising ultrasound field diffraction (2000) Proceedings of the 25th Acoustical Imaging, 25, pp. 131-136. , edited by Michael Halliwell and Peter N. T. Wells (ISBN 0-306-46516-7)Button, V.L.S.N., Costa, E.T., Maia, J.M., Dantas, R.G., Diffractive limited acoustic field of an apodized ultrasound transducer (2000) SPIE's International Symposium on Medical Imaging 2000, 3982, pp. 132-141. , ISBN: 0-8194-3599-6Stephanishen, P.R., Transient radiation from pistons in an infinite planar baffle (1971) Journal of Acoustical Society of America, 49 (5 PART 2), pp. 1629-1638Weight, J.P., Hayman, A.J., Observations of the propagation of very short ultrasonic pulses and their reflection by small targets (1978) Journal of Acoustical Society of America, 63 (2), pp. 396-404Weight, J.P., Restori, Diffraction effects in the pulsed and continuous wave fields (1986) Proceedings of Institute of Acoustics, 8 (PART 2), pp. 103-111Brittain, R.H., Weight, J.P., Fabrication of non-uniformly excited wide-band ultrasonic transducers (1987) Ultrasonics, 25, pp. 100-106. , MarchJaffe, B., Cook, W.R., Jaffe, H., (1971) Pizoelectric Ceramics, pp. 7-48. , Academic Press, London and New Yorkchs. 2 and 3(1978) IEEE Standard on Piezoelectricity, pp. 43-44. , ANSI/IEEE Std 176-1978