Overview
ISO 22444-2:2020 - Rare earth - Vocabulary - Part 2: Metals and their alloys is an ISO international standard that defines the terminology and key concepts used for rare earth metals, rare earth alloys, and the methods of preparation and purification. Prepared by ISO/TC 298 (Rare earth), this part of the ISO 22444 series provides a common vocabulary to unify technical terms across production, inspection, trading, scientific research and education.
Key topics
The standard organizes and defines terms in several practical domains:
- Fundamental definitions - what constitutes a rare earth metal, individual vs mixed rare earth metal, mischmetal, Pr–Nd (didymium) and other named materials.
- Purity and impurity terms - rare earth impurity, non‑rare earth impurity, interstitial impurity, absolute and relative rare earth metal purity, and rare earth metal content.
- Alloy classifications - definitions for rare earth alloy, master alloy, ferroalloy, rare earth‑modified alloys (Al, Mg, Cu, Ti), and specific intermetallic compounds such as Nd‑Fe‑B, Sm‑Co, La‑Ni, Gd‑Si‑Ge, and Tb‑Dy‑Fe.
- Preparation and purification methods - standardized names and brief descriptions for processes such as metallothermic reduction, silicothermic (ferrosilicon) reduction, carbothermic reduction, reduction‑distillation, intermediate alloy method, molten salt electrolysis, reduction‑diffusion (R‑D) and co‑reduction.
- Measurement/derived terms - terms like average atomic mass of rare earths in mixed metals, with worked examples and calculation guidance.
Applications and users
ISO 22444-2:2020 is intended as a reference to reduce ambiguity and trade disputes by standardizing vocabulary. Typical users include:
- Producers and alloy manufacturers - for consistent product specifications and material declarations.
- Quality and inspection labs - to harmonize reporting of impurities, purity levels and compositional descriptors.
- Procurement, traders and regulators - to clarify contract terms, material grading and acceptance criteria.
- Researchers and educators - as a reliable terminological resource when publishing or teaching about rare earth metallurgy and processing.
Practical value / SEO keywords
Using ISO 22444-2:2020 helps ensure consistent communication on rare earth metals, rare earth alloys, vocabulary, preparation methods and purification processes, improving interoperability across supply chains, compliance workflows and scientific publications.
Related standards
- Part 1 of the series (ISO 22444‑1:2020) contains basic properties and terminology for individual rare earth elements; the complete ISO 22444 series can be found on the ISO website and the ISO Online Browsing Platform.
