microcrevices

Microcrevices are tiny surface or near-surface cracks at the micrometer scale that occur in solids, including metals, polymers, ceramics, and rocks. They are typically invisible to the unaided eye and can form in new materials or develop during service.

Microcrevices arise from a combination of mechanical, thermal, chemical, and manufacturing factors. Mechanical processes such as machining, grinding, and finishing can introduce microscopic damage. Thermal cycling and residual stresses can drive crack formation, while chemical attack or crevice environments can promote localized corrosion within confined spaces. Manufacturing defects and imperfect coatings can also seed microcrevices.

These features are usually narrow and shallow, but they can act as stress concentrators and crack initiation sites under load. In metals, microcrevices can accelerate fatigue crack growth and contribute to localized corrosion in creviced environments where fluids stagnate. In geology, microcrevices influence rock porosity and permeability by creating pathways for fluid flow and chemical weathering at small scales. In engineering surfaces, they can affect wear, lubrication retention, sealing performance, and overall durability.

Detection and study of microcrevices rely on high-resolution techniques such as scanning electron microscopy, optical or confocal microscopy, atomic force microscopy, and X-ray computed tomography. Surface roughness measurements and leakage observations can also indicate their presence. Their analysis supports failure analysis, quality control, and the development of more durable materials and coatings.

Mitigation strategies include improving surface finishes to reduce roughness, applying protective coatings or sealants, redesigning geometries to minimize crevice traps, selecting more corrosion-resistant materials, and controlling environmental and operational conditions to limit crevice formation and growth.