The role of statistical design in the development of electrostrictive materials

The role of statistical design in the development and optimization of ceramic products is examined with particular reference to lead magnesium niobate/lead titanate (PMN-PT) ceramic dielectrics. It is shown that considerable benefits can be derived by following an appropriate design in which a number of factors (processing parameters) are varied simultaneously while the system response such as density, dielectric constant, loss, etc. is monitored. If it is assumed that complex factor interactions (e.g., having greater than three factors) can be ignored, only a fraction of the whole factorial matrix need be examined. Even in cases where only eight factors are involved each having only two levels, useful information can be obtained from only 16 trials drawn from the total of 256 trials (2/sup 8/) required of a full factorial matrix. Such studies are valuable in screening and ranking the importance of the various factors on the system response. Examples of such screening designs and the subsequent modelling of the system response for the important process factors so identified are presented.