Efterhärdning

Efterhärdning is a general term for processes that continue or complete hardening, curing or strengthening of a material after an initial treatment. The word—literally "after-hardening"—is used in contexts such as polymers, composites, coatings, adhesives, metal heat treatments and construction materials to denote additional thermal, chemical or environmental exposure intended to develop final properties.

In polymers and fiber-reinforced composites, efterhärdning commonly refers to post-curing: holding parts at elevated temperature to advance cross-linking, reduce residual monomer, and stabilize dimensions and mechanical performance. In metals the concept can encompass tempering or aging treatments applied after quenching to adjust hardness, toughness and residual stresses. In concrete and mortars, controlled after-curing (moist curing) improves hydration and long-term strength.

Parameters that determine the outcome include temperature, duration, atmosphere (inert, oxidizing or moist), and applied pressure. Properly controlled efterhärdning can increase strength, wear resistance, dimensional stability and durability, and reduce volatile emissions or internal stresses. Conversely, inappropriate conditions may cause over-aging, embrittlement, distortion or surface degradation.

Terminology and specific methods vary between disciplines; more specialized terms such as post-curing, tempering or precipitation hardening may be used to describe particular mechanisms. Selection of efterhärdning regimes is based on material chemistry, intended properties and manufacturing constraints.