Grotestraat 172, 7607CZ, Almelo, NL +31657433639 info@pmc4u.nl

Powders are bulk materials, made from:

• Solids (the particles)

• Liquid (water on the surface of the particle, in the particle or in the air between particles)

• Gas (normally air, between particles or fibrous materials, can also be absorbed by particle however!)

How these three phases interact determines their behaviour thus making powders extremely complex materials

• Powders (particles, gases & liquids) and Particles(solid particles) are two fully separate  entities, one being a bulk assembly of 3 phases the latter being a collection of solids

• Much scientific debate has been ongoing about how to best characterize materials.

• Particle characterization allows for the determination of a large amount of specific detailed information about the particles and their properties e.g. Specific gas absorption of particles, surface texture etc

• Powder characterization allows for the behavioural analysis of the bulk assembly E.g. Flow properties, compressibility etc

• Obviously these sciences overlap since particle characteristics do contribute to powder behaviour. But particle characterization alone is not enough nor is it a good scientific approach to predicting bulk assembly/ powder behaviour

 

Particle characterization

 

  • Particle Size & Distribution
  • Shape
  • Surface Texture
  • Surface Area
  • Density
  • Cohesion
  • Adhesion
  • Elasticity
  • Plasticity
  • Porosity
  • Potential for electrostatic charge
  • Hygroscopicity
  • Hardness / Friability
  • Amorphous content

All of these detailed particle characteristics contribute to powder behaviour.

 

Powder Characterization 

 

Powder Behaviour = fn (particle characteristics) + fn (environmental factors like humidity and aeration of the powder) + fn (material of production equipment used) + fn (packing state of powder, consolidated, loose, fluid like) + fn (MANY MORE FACTORS)....

This is why at PMC4U we look at the bulk assembly when predicting powder behaviour in specific environments or circumstances.

 

Important things to recognize:

  • Particle properties do not always influence powder behaviour or only part influence behaviour; a powder is a bulk assembly that as a whole also is prone to different stress regimes that influence the packing state.
  • Your material is exposed to many different stress regimes during your processes
  • Gaining predictive insights into behaviour of your material during specific processes allows for more lean management of the whole process and thus cost reductions overall
  • If your material does not behave as required under specific conditions this may influence your final product