metalenceramische

Metalenceramische, or metal-ceramic composites, are a class of materials that combine ceramic phases with a metallic phase to form a single material system. They are designed to blend the hardness and wear resistance of ceramics with the toughness and damage tolerance of metals, yielding properties intermediate between conventional ceramics and metals. The term can refer to either a ceramic matrix reinforced by metal or a metal matrix containing ceramic inclusions, with cemented carbides (cermets) being a common example.

The most widely known metalenceramische system is tungsten carbide grains embedded in a cobalt (or nickel) binder, producing WC-Co cemented carbide. Other systems use ceramic particles such as TiC, TiN, Al2O3, or SiC within Ni-, Fe-, or Co-based metal matrices. Microstructure—particle size, distribution, and porosity—greatly influences hardness, strength, and fracture behavior, as does the ratio of ceramic to metal.

Fabrication typically employs powder metallurgy: blending ceramic and metal powders, pressing, and sintering. Advanced methods include hot isostatic pressing, spark plasma sintering, and certain additive manufacturing techniques, which allow finer microstructures and more complex shapes. Key properties include high hardness and wear resistance, good compressive strength, and improved fracture toughness relative to pure ceramics, though still more brittle than many metals. Thermal stability varies with materials chosen, and oxidation can degrade high-temperature performance in some systems.

Applications span cutting tools, mining and drilling components, wear parts, and components operating in harsh or high-temperature environments. Challenges include production cost, processing complexity, residual stresses, and limited thermal shock resistance for some formulations. Ongoing research seeks to tailor phase content and microstructure to enhance toughness and stability while preserving hardness.