Particles can be described by a great number of properties, most of which exhibit wide fluctuations within a sample. In order to have greater understanding of particulate behaviour it is important to understand the particle characteristics, such as size and shape, mechanical properties, adhesive properties etc. Particle size is a simple concept that is complicated by the particle shape. Particles can rarely be described suitably by one single sieve diameter, hence a great number of descriptors exist for characterising particle shape.

The response of a particle to compression is governed by mechanical properties, such as Young’s modulus, hardness and fracture toughness. Breakage of particles is governed by these properties, as such measurement of these properties can provide some insight into particle failure.

A degree of adhesion is usually present between particles and any surfaces they contact. The magnitude of this adhesive force is dependent on the surface chemistry and the size of the particles. Our research group has developed a quick and simple test device for estimating the characteristic adhesive force for a bulk sample. This approach, known as the drop test method, applies a rapid deceleration force to particles adhered to a substrate. Contacting particles must also overcome friction in order to slide past one another. The frictional force between particles can be assessed using a pin-on-disk device known as the Micromaterials NanoCrush.

Our research group has access to a number of devices for characterising particles:

  • Sieve shakers – for size analysis
  • Malvern Mastersizer 2000 – for size analysis by laser diffraciton
  • Malvern Morphologi (G3) – for size analysis by imaging
  • Micromaterials NanoTest – for determining hardness, Young’s modulus and fracture toughness by nanoindentation
  • Drop Test – for measurement of single particle adhesion
  • Micromaterials NanoCrush – for measurement of friction and mechanical strengh testing of single particles
  • Nanotom XRT – for particle shape analysis

Related Publications

  1. Zafar, U., Hare, C., Hassanpour, A., and Ghadiri, M.,”Drop Test: A New Method to Measure the Particle Adhesion Force “, Powder Technology, Submitted
  2. Liu, Y., Calvert, G., Hare, C., Ghadiri, M., Matsusaka, S., 2012, ” Size measurement of dry ice particles produced from liquid carbon dioxide “, Journal of Aerosol Science, 48, 1-9.
  3. Olusanmi, D., Roberts, K., Ghadiri, M., Ding, Y. 2011. “The breakage of Aspirin under quasi-static indentation and single particle loading: Effect of crystallographic anisotropy”, International Journal of Pharmaceutics, 411(1-2), 49-63.
  4. Supuk, E., Seiler, C., and Ghadiri, M., 2009, “Analysis of a Simple Test Device for Tribo-Charging of Bulk Powders”, Particle and Particle Systems Characterization, 26, 7-16.
  5. Watanabe, H., Ghadiri, M., Matsuyama, T., Ding, Y., Pitt, K.G. , 2007, “New instrument for tribocharge measurement due to single particle impacts”, Review of Scientific Instruments, 78(2), 024706/1-024706/5.
  6. Hassanpour, A. and Ghadiri, M., 2007, “Characterisation of flowability of loosely compacted cohesive powders by indentation”, Particle and Particle Systems Characterisation, 24 (2), 117-123.
  7. Hassanpour, A., Ghadiri, M. , 2004, “Distinct element analysis and experimental evaluation of the Heckel analysis of bulk powder compression”, Powder Technology, 141, 251-261.