Overview
EN ISO 21068-2:2024 (ISO 21068-2:2024) specifies standardized analytical methods for the chemical analysis of raw materials and refractory products that contain silicon‑carbide (SiC), silicon‑nitride, silicon‑oxynitride and SiAlON. The standard covers procedures to determine volatile components, total carbon, free carbon, silicon carbide content, total and free silicon, and free and surface silica. It replaces EN ISO 21068-2:2008 and is intended for laboratories, manufacturers and quality‑control teams working with refractory ceramics and Si‑based raw materials.
Key Topics
- Determination of volatile components
- Gravimetric methods including loss on drying at 250 °C and loss on ignition in argon (LOIAr).
- Total carbon measurement
- Combustion techniques: resistance furnace with decomposing agents (e.g., lead borate or tin) and induction furnace (IF) methods with metallic powder.
- Detection: coulometry, infrared (IR) CO2 detection, thermal conductivity (TC).
- Free carbon determination
- Covers direct and indirect methods, procedural steps, calculations and considerations for accuracy.
- Silicon carbide (SiC) quantification
- Indirect and combustion-based procedures, including combustion at elevated temperatures (e.g., 750 °C) and residue analysis.
- Silicon analysis
- Total silicon and free silicon measurements, including acid pretreatment (HCl) and hydrogen evolution techniques for free silicon determination.
- Silica (SiO2)
- Determination of free silica and surface silica content with prescribed pretreatments and calculation methods.
- Quality controls
- Sample preparation, test assembly, blank tests, calculation formulas and precision statements are included to ensure reproducibility.
Applications
- Quality control and acceptance testing of refractory products, SiC refractories and raw powders.
- Material characterization in R&D labs developing Si‑based ceramics and composites.
- Supplier qualification, batch verification and failure analysis where carbon, silicon and silica phases affect material performance.
- Regulatory and certification testing when standardized analytical evidence is required.
Who Should Use This Standard
- Industrial testing laboratories and metrology labs
- Refractory and advanced ceramics manufacturers
- Research institutions focused on silicon‑based refractory materials
- Procurement and quality assurance teams specifying material conformity
Related Standards
- EN ISO 21068 series (other parts for complementary analyses)
- National and ISO standards on combustion, gravimetric and spectrometric detection methods (referenced normative documents within EN ISO 21068-2:2024)
Keywords: EN ISO 21068-2:2024, ISO 21068-2:2024, silicon carbide analysis, refractory materials testing, total carbon determination, free silica measurement.
