Overview
ISO 24235:2007 is an international standard that specifies a laser diffraction method for determining the particle size distribution of fine ceramic powders, also known as advanced or technical ceramics. This method measures how laser light is scattered at different angles by particles dispersed in a liquid, enabling precise characterization of particle sizes typically ranging from 0.1 µm to 50 µm. The standard aims to ensure consistent, accurate measurement practices for fine ceramic powders used in industrial and research applications related to advanced ceramics.
Key Topics
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Measurement Principle
The technique relies on illuminating ceramic powder particles suspended in a liquid phase with a collimated laser beam. The laser light scatters at angles dependent on particle size, shape, and refractive index. Detectors capture the angular distribution of scattered light, and the data is mathematically analyzed using scattering theories such as Mie or Fraunhofer diffraction to calculate the size distribution.
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Equipment Requirements
The standard outlines essential apparatus including:
- Laser light source (typically He-Ne or semiconductor lasers)
- Beam expander/collimator to generate a parallel laser beam
- Dispersion tank with stirring and circulation pump to keep particles suspended
- Fourier lens and multiple detectors positioned to capture forward, side, and back-scattered light
- Ultrasonic dispersers for sample preparation to break down agglomerates
- Data processing systems for converting signals into particle size distributions
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Sample Preparation
Sample handling must follow procedures for representative sampling (ISO 3082), particle dispersion (ISO 14703), and dispersion media selection (ISO 14887). Proper ultrasonic treatment and dispersion are crucial to avoid particle aggregation and ensure reliable measurement.
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Measuring Procedure
Operators are guided through calibration, medium circulation, background measurement, suspension injection, and data acquisition steps to obtain accurate particle size distribution results. Inputs such as refractive indices of particles and media must be correctly entered for precise analysis.
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Reporting Results
Results are reported as cumulative volume percentage distributions, with particle size values at 10%, 50% (median), and 90% volume cumulative levels. Complete documentation of measurement conditions and sample preparation, including equipment specs and dispersion media, is mandated to support reproducibility.
Applications
ISO 24235:2007 is vital for industries and laboratories working with fine ceramic powders, ensuring consistent particle size characterization to enhance material performance and quality control. Common application areas include:
- Advanced ceramics manufacturing: Optimizing powder properties for sintering, mechanical strength, and thermal resistance.
- Electronics and semiconductors: Controlling particle size for dielectric and conductive ceramic components.
- Automotive and aerospace: Assuring the quality of ceramic materials for sensors, insulators, and engine components.
- Research and development: Studying powder behavior, developing new ceramic materials, and improving processing techniques.
Related Standards
- ISO 13320-1:1999 – Particle size analysis using laser diffraction general principles.
- ISO 14703:2000 – Sample preparation for fine ceramic powders particle size determination.
- ISO 14887:2000 – Dispersion procedures for powders in liquids.
- ISO 3082:2000 – Sampling and sample preparation for iron ores (methodological relevance for powder sampling).
Utilizing ISO 24235 alongside complementary standards ensures standardized, accurate particle size measurements necessary for quality assurance and innovation in fine ceramics industries.
Keywords: ISO 24235:2007, laser diffraction, particle size distribution, fine ceramics, advanced ceramics, ceramic powders, particle measurement, Mie scattering, Fraunhofer diffraction, dispersion medium, ultrasonic disperser, particle size analysis, technical ceramics standards, powder characterization.