Metal porous material testing service

Metal Porous Material Testing Service – Comprehensive Characterisation and Performance Validation for Brazilian Filtration, Energy and Industrial Applications

As an ISO/IEC 17025 accredited independent testing laboratory, we provide comprehensive testing services for metal porous materials – including sintered metal powders, metal foams, woven wire meshes, and perforated or expanded metal sheets – used across Brazilian filtration, catalysis, energy storage, heat exchange, noise control, and biomedical sectors. Metal porous materials offer unique combinations of permeability, mechanical strength, thermal stability, and corrosion resistance, but their performance depends critically on pore structure, porosity, permeability, mechanical integrity, and cleanliness. Our test protocols quantify these parameters using internationally recognised methods aligned with ABNT NBR standards, ISO 4003 (Bubble test method for determining the pore size), ISO 4022 (Permeable sintered metal materials – Determination of fluid permeability), ASTM E128 (Pore size characteristics of rigid porous filters), ASTM B328 (Density and interconnecting porosity), ISO 2738 (Sintered metal materials – Determination of density and open porosity), ASTM E362 (Constant‑rate tensile test for metal powders), and ISO 13314 (Mechanical testing of metallic porous materials – Compression test). Our reports are recognised by INMETRO (product certification), ABNT (technical compliance), ANP (oil and gas equipment qualification), IBAMA (environmental filtration), and Brazilian engineering and manufacturing firms for quality assurance, material selection, and supplier qualification.

Types of Metal Porous Materials We Regularly Test

Our laboratory accommodates a wide variety of metal porous products, from fine‑pore filters to high‑porosity foams. Typical test specimens include:

• Sintered metal powder filters – bronze, stainless steel, nickel, titanium, and Monel® elements
• Metal fiber felt and sintered fiber media – for high‑temperature gas filtration and coalescence
• Metal foams (open‑cell) – aluminium, copper, nickel, and steel foam for heat exchangers and battery electrodes
• Woven and knitted wire meshes – for screening, sieving, and support layers
• Perforated and expanded metal sheets – for acoustic panels, grating, and battery current collectors
• Porous metal membranes – for microfiltration and ultrafiltration applications
• Additively manufactured porous structures – lattice and gyroid designs for orthopaedic implants and lightweight components
• Catalytic supports and electrode substrates – with controlled pore gradients

Pore Structure Characterisation – Bubble Point, Pore Size Distribution and Permeability

• Bubble point and maximum pore size (ISO 4003 / ASTM E128 / ABNT NBR 11861) – We immerse the test specimen in a wetting liquid with known surface tension (e.g., isopropanol or perfluoroether) and pressurise it from one side with air or nitrogen. The first steady stream of bubbles on the downstream side is detected, and the pressure is recorded. The maximum pore diameter is calculated using the Young‑Laplace equation: D = (4 × γ × cos θ) / ΔP, where γ is the surface tension of the wetting liquid, θ is the contact angle, and ΔP is the differential pressure. The test is performed on at least five specimens per batch, and the average maximum pore size (in µm) and the standard deviation are reported. For Brazilian filtration applications, a maximum pore size of less than 50 µm is typical for fine filtration, while 100‑500 µm is used for coarse filtration.
• Bubble point distribution and pore size distribution (capillary flow porometry) – Using a capillary flow porometer, we generate a flow‑vs‑pressure curve during the wetting and drying cycle. The differential pressure at which the dry and wet flow curves intersect provides the mean flow pore size. The software calculates the full pore size distribution (from the smallest to the largest pores) and reports the percentiles (D10, D50, D90). A narrow distribution (e.g., D90/D10 < 2) indicates a uniform pore structure, which is critical for consistent filtration efficiency.
• Permeability to air or liquid (ISO 4022 / ASTM D6539 adapted) – We mount the porous specimen in a sealed cell and measure the volumetric flow rate (in L/min or m³/h) of air or water through the specimen at a specified differential pressure (typically 1‑10 kPa). The specific permeability (in m² or darcy) is calculated from Darcy’s law: K = (Q × μ × t) / (A × ΔP), where Q is the flow rate, μ is the fluid dynamic viscosity, t is the thickness, A is the cross‑sectional area, and ΔP is the pressure drop. We report the specific permeability and the pressure drop per unit thickness (ΔP/mm). For Brazilian oil‑field filtration, a minimum permeability of 1 × 10⁻¹² m² is often required.
• Porosity (open, closed and total) – ISO 2738 / ASTM B328 / ABNT NBR 14121 – We determine the open porosity by the water‑immersion or oil‑impregnation method. The dry weight (md) is measured, then the specimen is vacuum‑impregnated with a fluid, and the saturated weight (ms) is measured. The open porosity (in %) is calculated as P_open = [(ms – md) / ρ_fluid] / V, where V is the bulk volume. The bulk volume is measured by mercury displacement or by dimensional measurement. The total porosity is estimated from the true density (by helium pycnometry) and the bulk density. For Brazilian catalyst supports, an open porosity of 30‑50 % is typical.

Mechanical and Structural Integrity – Compressive, Tensile and Crushing Strength

• Compressive strength of metal foams and sintered materials (ISO 13314 / ASTM E9 adapted) – We machine cylindrical or prismatic specimens and compress them in a universal testing machine at a crosshead speed of 1‑5 mm/min until they yield or fracture. We record the compressive yield strength (in MPa), the compressive modulus (in GPa), and the energy absorption capacity (in J/cm³) by integrating the stress‑strain curve. The plateau stress and the densification strain are also reported. For Brazilian lightweight structural applications, a plateau stress above 10 MPa is often required.
• Tensile strength of porous metal sheets and fiber felts (ASTM E8 / ISO 2740 adapted) – For open‑cell foams and sintered fiber materials, we test flat specimens cut in the rolling or pressing direction. The maximum tensile strength (in MPa), the elongation at fracture, and the modulus of elasticity are measured. A low tensile strength (e.g., < 5 MPa) may indicate poor sintering or internal defects, which would be unacceptable for Brazilian filter cartridges subjected to pressure surges.
• Crush resistance of metal powder filter elements (ISO 2739 / ASTM B429) – For tubular filter elements, we apply a radial compressive load (using a diametral compression test) and record the maximum load before fracture. The load is expressed in kN per unit length. The crush strength is compared to the design specification; a value below the specified minimum is flagged for Brazilian high‑pressure gas filtration systems.
• Fatigue life under cyclic pressure (ASTM E606 / ISO 12108 adapted) – For filters subjected to cyclic differential pressure (e.g., back‑pulse cleaning), we apply a sinusoidal pressure cycle (0‑500 kPa) at 1 Hz for 100,000 cycles and inspect for cracking or permeability loss. Any significant increase in pressure drop (> 20 %) is reported as fatigue damage.

Corrosion Resistance and High‑Temperature Performance – Environmental Durability

• Salt spray corrosion test for porous metals (ASTM B117 / ABNT NBR 8096) – We expose porous metal specimens (in their final form) to a 5 % NaCl fog at 35 °C for 240 or 500 hours. After exposure, we inspect for red rust, pitting, or any loss of structural integrity. A weight loss of less than 0.5 % is considered excellent. For Brazilian marine and coastal filtration installations, this test is mandatory.
• Intergranular corrosion test for stainless steel porous materials (ASTM A262 / ISO 3651) – For austenitic stainless steels (e.g., 316L), we perform a corrosion test in boiling nitric acid or ferric sulfate‑sulfuric acid solution and examine the microstructure for intergranular attack. Any susceptibility is reported, which is critical for Brazilian chemical and petrochemical filter applications.
• High‑temperature oxidation resistance (ASTM G54 / ISO 10462 adapted) – We expose porous specimens in a muffle furnace at the service temperature (e.g., 600 °C, 800 °C, 1,000 °C) for 100‑1,000 hours in air. The weight gain (due to oxide formation) and any change in pore size (measured by bubble point) are recorded. An acceptable weight gain is typically < 5 mg/cm² for Brazilian high‑temperature filtration and catalytic support applications.
• Thermal cycling and dimensional stability – We subject the material to 10 thermal cycles from ambient temperature to the maximum service temperature (e.g., 500 °C) and back, then re‑measure the porosity and permeability. A change in porosity of more than 5 % or a change in permeability of more than 20 % is reported as thermal ageing degradation.

Cleanliness and Contamination Assessment – Filtration Efficiency and Particulate Retention

• Bacterial retention test (for biomedical and pharmaceutical filtration) – ASTM F838 / ISO 10993 adapted – We challenge the porous metal filter with a suspension of Brevundimonas diminuta (ATCC 19146) at a concentration of 10⁷ CFU/cm² and measure the effluent bacterial count. A retention of ≥ 10⁷ CFU/cm² is considered a valid bacterial filter, which is required for Brazilian pharmaceutical and medical gas filtration.
• Particulate removal efficiency (by gravimetric or particle counting) – We pass a test aerosol or suspension containing particles of known size (e.g., ISO 12103‑1 test dust) through the porous specimen and measure the upstream and downstream particle concentrations using an optical particle counter or gravimetric filter. The removal efficiency (in %) is reported for each particle size fraction. For Brazilian industrial air filtration, an efficiency > 99.5 % for particles > 0.3 µm is typical.
• Extractable and leachable substances (for pharmaceutical and food contact) – USP <87> / USP <88> – We extract the porous metal filter with water, ethanol, and hexane, and analyse the extractables using gravimetry, TOC, and HPLC. The total extractable mass (in mg) and any specific leachable compounds (e.g., heavy metals) are reported. A result below the USP limit for plastics (e.g., < 5 mg per filter) is acceptable for Brazilian pharmaceutical products.
• Cleanability and back‑flushing efficiency – We contaminate the filter with a standard dirt load, then clean it by back‑flushing (reverse flow) and re‑measure the permeability. The permeability recovery percentage is reported; a recovery of ≥ 80 % is typically required for Brazilian reusable filtration systems.

Microstructural Characterisation – Grain Size, Sintering Quality and Defect Detection

• Metallographic examination (ASTM E3 / ISO 4496) – We prepare cross‑sections of porous specimens, mount them in resin, grind and polish, and examine them under an optical microscope (50‑1,000×) to assess the sintering neck development, grain boundaries, pore shape, and any cracks. We report the average grain size (in µm) and the extent of interparticle bonding, which is critical for predicting mechanical strength.
• Scanning electron microscopy (SEM) with energy‑dispersive X‑ray (EDX) analysis – For detailed pore morphology and elemental analysis, we use SEM to capture high‑resolution images of the pore structure and to detect any impurities, inclusions, or localised corrosion. The presence of chloride, sulfur, or other contaminants is reported, helping Brazilian manufacturers trace contamination sources.
• X‑ray computed tomography (CT) – for 3D pore network visualisation – For advanced characterisation, we perform non‑destructive CT scanning (resolution down to 5 µm) to reconstruct the 3D pore network, measure the pore connectivity, and detect closed porosity or macroscopic defects. The tortuosity and coordination number are reported for Brazilian catalyst and battery electrode developers.
• Phase composition analysis (XRD) – for alloy verification – We perform X‑ray diffraction to confirm the metallic phase composition and to detect any unwanted intermetallic phases or oxides that may affect performance. The results are compared to the certified material specification.

Report Acceptance & Compliance with Brazilian Oil, Gas, Chemical and Biomedical Standards

All metal porous material tests described above are conducted under our ISO/IEC 17025:2017 accreditation, using calibrated bubble point testers, porosimeters, permeameters, universal testing machines, microscopes, and spectrometers traceable to INMETRO and international reference standards. Our final test reports include: a comprehensive description of the material (composition, manufacturing method, nominal pore size), a summary of all measured parameters (maximum pore size, mean flow pore size, permeability, porosity, compressive/tensile strength, corrosion rating, cleanliness data), statistical summaries (mean, standard deviation, coefficient of variation), high‑resolution images (optical, SEM, CT), and a clear pass/fail verdict against your specified acceptance criteria or reference standard (e.g., ISO 4003 compliance, minimum bubble point, maximum extractables). We also provide an expanded uncertainty (k=2) for key quantitative parameters. These reports are widely accepted by INMETRO for product certification of filters and porous components, by ANP for oil‑field equipment qualification, by ANVISA for pharmaceutical filtration and biomedical devices, by ABNT for normative compliance, and by Brazilian engineering firms, chemical plants, and material suppliers for quality assurance, material selection, and process optimisation. Bilingual (Portuguese/English) versions are available to facilitate submissions to regulatory bodies and to support your engineering, quality, and procurement teams. With our rigorous and comprehensive testing service, you can confidently validate the pore structure, mechanical integrity, and durability of your metal porous materials, ensuring reliable and efficient performance in Brazil's most demanding industrial and environmental applications.