ESTIMATION OF MEAN PARTICLE-SIZE FROM SINGLE SECTIONS

The usual size descriptors for three-dimensional (3D) particles are vo lume (V), surface area (S) and, to a lesser extent, mean height (H), t he mean being over isotropic directions in space. With these parameter s we can construct 12 weighted means for the particle population, name ly {E-Y(X), X = H, S, V and Y = N, H, S, V}, where E-Y(X) represents t he population mean of the parameter X weighted by the parameter Y. The ordinary means are the number-weighted ones, namely {E-N(X), X = H, S , V}, whose estimation is only possible using a 3D probe (notably the disector) to sample the particles. In this paper we describe a general strategy to estimate E-Y(X) and consider in detail the estimation of E-S(V) and E-V(S); unbiased estimators have been proposed for both wei ghted means from single or independent sections, but to our knowledge the corresponding sampling and estimation procedures have not yet been illustrated with real data. We do this here for the tungsten particle s in a cemented carbide.