Meaning
Standardized measurement guidelines for particle size analysis using light scattering methods provide cross-industry consistency in powder characterization. The laser diffraction ISO 13320 standard establishes requirements for optical alignment, sample dispersion, and instrument validation across a wide range of materials. This specification covers both wet and dry measurement systems, ensuring that laboratories use comparable calculations to report size distributions.
Industrial supply chains rely on this standard to define particle metrics.
Optical Principle
Particle suspension passes through a laser beam, causing the light to scatter at angles that are inversely proportional to particle size. Compliance with laser diffraction ISO 13320 requires using either the Mie scattering theory or the Fraunhofer approximation to convert the angular intensity of scattered light into a volumetric size distribution. The Mie theory is preferred for sub-micron particles because it accounts for the refractive and absorptive index of the material.
Modern instruments measure the light intensity over a wide range of angles to generate accurate, high-resolution size distribution curves. This ensures that the instrument’s detector array captures the scattering signals from both very large and very small fractions within the same sample.
Dispersion Parameter
Achieving reproducible sizing results requires complete deagglomeration of the powder sample before it enters the measurement zone. The laser diffraction ISO 13320 standard outlines how to optimize dispersion pressures for dry powders and surfactant concentrations for wet suspensions. Over-dispersing can break fragile particles, while under-dispersing results in agglomerates being measured as single large particles.
Both errors distort the reported particle sizes.
Quality Standards
Instrument validation involves measuring certified reference materials, such as spherical glass beads, to verify that the measured size lies within acceptable tolerance bands. Operating under laser diffraction ISO 13320 gives procurement departments confidence that the reported particle diameters, such as the median value, are accurate and reproducible. This reduces the risk of process variations when the powder is incorporated into battery electrode slurries.
