At Phosphor Technology, we are equipped to perform particle size analysis on materials ranging from approximately 1 micron up to 150 microns using in-house equipment.

At Phosphor Technology Ltd, we test all supplied materials for particle size data. The results accompany the material as part of the service we provide. For a modest charge we can also analyse materials provided by a customer.

A Coulter Multisizerâ„¢ 3 provides the primary measurement of particle size median and spread. Confirmation of the measurement is achieved through microscopic analysis, so that materials that suffer from severe agglomeration or hydrolysis will not generate incorrect results.

The standard measurement procedure uses an aqueous electrolyte. We have also established a procedure using a non-aqueous electrolyte. With this procedure we can measure materials that will react with aqueous solutions.

The reporting of results is in a way that represents the spread of particle sizes as well as the median particle size. Following common industry practice, we report results by listing a particle size against a percentage number. These percentages remain constant: 5%, 25%, 50%, 75%, 95%; as shown in the example below.


Each percentage represents a bottom fraction of the particle size range. The particle size reported against that fraction is the top-end particle size in that fraction. Fractions are based on the volume of material, so we talk about 5% of the total volume taken up by the material rather than 5% of the total number of particles. Reading from the example, we can say that the bottom 5% of particle sizes are less than or equal to 2.4 microns and that the bottom 25% of particle sizes are less than or equal to 3.5 microns. The particle size reported at 50% is the median particle size.

A quartile deviation is also calculated from the values at 25% and 75%. The calculation is as follows:

Q. D. = ([75%]-[25%]) / ([75%]+[25%])

e.g., Q. D. = (6.5-3.5) / (6.5+3.5) = 3.0 / 10.0 = 0.30

Typical values will range from 0.20 to 0.35, anything less has a very narrow spread, and anything more has a very broad spread.

As a further service we can also generate scanning electron micrographs (SEMs) of the material. As well as showing the general particle size, an SEM can also display the morphology of the material.

To submit samples for testing, please relay any information you have regarding the samples to us. A general idea on particle size and any information on possible instability of the material will allow the testing to proceed more efficiently.