eimetalliset

Eimetalliset is a Finnish-language term used in materials science to denote a broad class of substances whose properties are dominated by non-metallic bonding and structure. The term serves as a counterpart to metals and metal alloys and is commonly encountered in introductory textbooks and industry reports within Finland. In practice, eimetalliset encompass ceramics, glasses, polymers, and many composites, but exclude metallic conductors and metal-based composites.

Characteristic features of eimetalliset include high electrical resistivity, often high hardness and brittleness (especially in ceramics), variable thermal conductivity, and chemical inertness in many environments. They typically exhibit low to moderate density compared with metals and tend to form covalent or ionic bonds rather than metallic bonding. Optical properties vary widely, ranging from transparent glasses to opaque polymers.

Processing of eimetalliset relies on methods such as powder sintering and ceramic shaping, glass forming, polymerization, and composite fabrication. Challenges include brittleness, processing shrinkage, and compatibility between different subgroups, such as ceramics and polymers in a composite. Advances focus on improving toughness, impact resistance, and thermal stability.

Applications span electrical insulation, architectural materials and glazing, wear-resistant parts, optical components, packaging, and biomedical devices, where inertness and biocompatibility are advantageous. In research, eimetalliset are studied for their environmental resistance, dielectrics, and performance under extreme temperatures.

Etymology and usage: The name derives from the Finnish prefix ei- meaning 'not' and metalliset meaning 'metals'—reflecting its role as a category separate from metallic substances. While widely used in Finnish contexts, the term is less common in English-language literature, which more often uses 'non‑metals' or 'ceramics, polymers, and glasses' to describe the same class.