Porefree

Porefree (often written as pore-free or porefree) is a descriptor used in materials science to denote materials or surfaces with negligible porosity. A porefree material has a density approaching the theoretical maximum and contains few, if any, interconnected voids that would permit fluid or gas transport. The term is typically applied to dense ceramics, metals, polymers, and coatings where impermeability and barrier properties are essential.

Key properties of porefree materials include high density, very low permeability to liquids and gases, and strong mechanical or thermal barriers. They usually exhibit excellent chemical resistance and can provide a smooth surface finish. In practice, porefree implies the absence of open porosity and a minimal presence of closed porosity, achieved through specialized processing.

Producing porefree materials involves techniques aimed at eliminating or sealing voids. In metals and ceramics, processes such as hot isostatic pressing, spark plasma sintering, vacuum degassing, and diffusion bonding are used to close internal pores. Forging and rapid solidification can also reduce porosity. In coatings and films, dense deposition methods like chemical vapor deposition, physical vapor deposition, and atomic layer deposition help form nonporous layers. Post-processing sealing treatments may be applied to eliminate micro-pores at surfaces.

Applications of porefree materials occur where impermeability and strength are critical. Examples include aerospace components and turbine parts, medical implants requiring reliable barrier properties, protective coatings for corrosion resistance, and barrier layers in electronics and packaging. It is important to note that achieving true porefreeness can be costly and challenging, and in some contexts controlled porosity may be desirable.

Measurement and verification of porefreeness rely on density assessments, porosimetry, X-ray computed tomography, and surface or cross-sectional imaging to detect residual porosity.