Pore size measurement in metal filter media: challenges and solutions
Metal filter media are widely used thanks to their durability, high-temperature resistance and corrosion protection. From woven meshes and expanded foils to sintered discs and foams, they play a key role in oil and gas, chemical processing, sterile medical filtration and catalyst recovery.
But their diverse structures make pore size characterization far from straightforward.
The challenge of measuring pore size in metals
Metals can be manufactured through multiple fabrication techniques, each leaving a different pore architecture. A perforated sheet has predictable, uniform pores, while sintered discs or foams feature tortuous and irregular channels.
This diversity leads to several measurement difficulties:
Thickness variation: from fragile electroformed sieves to dense sintered discs several millimeters thick.
Wettability issues: not every wetting liquid interacts properly with metals.
Geometry effects: irregular pore shapes create unpredictable pore neck constrictions.
Mechanical fragility: thin meshes and foils risk damage under pressure.
Relying on microscopy alone often fails to capture these complexities, making a robust pore size measurement technique essential.
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Capillary flow porometry as a solution
Capillary flow porometry offers a practical and reliable way to determine through-pore size, pore size distribution and permeability in metal filters. The method works by wetting the porous structure and measuring the flow of gas as pressure gradually displaces the liquid.
Two complementary instrument families address these challenges:
POROLUX™ Cito series: pressure scan porometers that provide fast and reproducible results, suitable for quality control of thin and open metal samples.
POROLUX™ Revo series: step stability porometers with patented MP² technology, delivering accurate measurements of thick or tortuous samples.
Both series measure parameters such as bubble point, mean flow pore, smallest pore, pore size distribution and gas permeability. Specialized sample holders ensure that fragile meshes or thick discs can be tested safely.
Insights from the application note
In our recent study, we tested a range of metal media, including woven meshes, metal foams and sintered discs. Results show how coating, thickness and pore architecture influence pore size distribution. The measurement curves also demonstrate how these differences are reflected in the air permeability behaviour of the samples.
Why it matters
Accurate pore size characterization enables manufacturers and researchers to:
Compare the effect of fabrication techniques or surface treatments
Select the right media for demanding liquid or gas applications
Ensure consistent performance in industrial and medical filtration
Read the full application note
The full study provides detailed measurement data and comparative graphs of woven meshes, foams and sintered metals.
Download the application note on metal filter media
For more information on our instruments, visit the POROLUX™ product page.