ISO 9276-6:2008

Overview

ISO 9276-6:2008 - "Representation of results of particle size analysis - Part 6: Descriptive and quantitative representation of particle shape and morphology" - specifies rules, nomenclature and minimum descriptor sets for describing particle shape and morphology. The standard complements particle size data (see ISO 9276‑1) by defining how to represent shape quantitatively, especially for image-analysis-derived silhouettes. It focuses on methods that can be correlated with physical properties in industrial applications and emphasizes that simple averaging of shape is ineffective - distributions of shape-related characteristics are required in addition to size distributions.

Key topics and requirements

• Scope and intent: Define consistent terminology and representation rules so particle shape/morphology can be related to macroscopic properties.
• Evaluation criteria for shape descriptors: accessibility (computational cost), scope, uniqueness, stability/sensitivity, and invariance to rotation, reflection and scale.
• Classification of methods: qualitative (verbal) vs quantitative (numeric descriptors) and method classes suitable for industrial correlation.
• Levels of shape description:
  • Macroshape (overall form),
  • Mesoshape (roundness, corners),
  • Microshape (surface texture, roughness).
• Shape descriptors and normalization: minimum descriptor set derived for direct comparison of methods; use of size parameters to normalize shape metrics.
• Sources of error: image resolution, binarization, algorithmic calculation differences and their impact on descriptor robustness (Clause 6).
• Practical computation and presentation: normative equations (Annex A) and examples of data presentation (Annex B).
• Restriction to applicable methods: only descriptors that can be correlated with technological properties are prioritized.

Applications

ISO 9276-6 is intended for any process or product where particle shape affects performance, including:

• Powder flow, mixing and segregation analysis
• Abrasive/grinding performance and wear prediction
• Pharmaceutical solids (dissolution, compactibility)
• Materials science, ceramics, coatings, and food powders
• Image analysis and particle characterization workflows where morphology and texture matter

Who should use this standard

• Analytical laboratories performing particle size and shape characterization
• R&D and product development teams linking particle morphology to performance
• Quality assurance and process control engineers in powder-handling industries
• Manufacturers of particle-sizing and image-analysis instruments and software
• Metrology bodies defining measurement procedures and reporting

Related standards

• ISO 9276‑1 - Graphical representation and particle-size fundamentals
• ISO 13322‑1 / ISO 13322‑2 - Static and dynamic image analysis methods
• Other parts of ISO 9276 (Parts 1–5) covering statistical and graphical treatments of size data

Keywords: ISO 9276-6:2008, particle shape, particle morphology, particle size analysis, shape descriptors, image analysis, macroshape, mesoshape, microshape, particle characterization.