Thermal Spray Tips - Swinburne University of Technology

Compiled by Jo Ann Gan, Edited and advised by Christopher C. Berndt
Swinburne University of Technology Thermal Spray Group (SwinTS)
Please contact Prof. Christopher Berndt at cberndt @swin.edu.au for further enquiries
3.8. Particle Size Distribution Plots
Particle classification curves, (a) Cumulative plot (b) Frequency plot
A particle size distribution can be graphically represented as a cumulative plot or a frequency plot. These
graphs are essentially identical since they can be derived from each other; the summation of the
individual frequencies at each size enables the cumulative plot to be developed. The key features
conveyed from particle size distribution data are:
• The most commonly occurring particle size (i.e., the modal value) is indicated by the peak in the
frequency plot. The mean value can be determined from the diameter at the 50 wt% value of the
cumulative graph.
• The sharpness of the plot gives a qualitative indication of the spread in particle size. A sharp peak
indicates that the particles are of similar size, whereas a flat or broad curve indicates that the
particle sizes are spread over a wide range of values.
• The maximum and minimum values in measurable diameters allow the particle size range to be
determined.
• It is important to look for a distribution that does not fluctuate, because that indicates a bimodal
distribution of particle sizes. Such powders do not feed reliably.
Source: Particle Characterization, Christopher C. Berndt, Stony Brook University, as published in
Handbook of Thermal Spray Technology, J.R. Davis (Ed.), ASM International, 2005, p 164.
Information and data acquired from ASM International Thermal Spray Society
website at http://asmcommunity.asminternational.org/portal/site/tss/SprayTips/
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