Magnetic performance testing service

Magnetic Performance Testing Service – Accredited ISO/IEC 17025 Magnetic Property and Material Quality Assessment for the Croatian Market

Magnetic performance testing is a critical evaluation method used to determine the magnetic properties of materials, components, and assemblies used in a wide range of applications, including electrical motors, generators, transformers, sensors, actuators, magnetic separators, loudspeakers, and medical devices. The accurate measurement of parameters such as magnetic flux density, coercivity, remanence, permeability, and hysteresis loss is essential for ensuring the efficiency, reliability, and performance of electromagnetic systems. In the Croatian market, where the Hrvatski zavod za norme (HZN), the Ministarstvo gospodarstva i održivog razvoja, the Državni inspektorat, the Hrvatska regulatorna agencija za mrežne djelatnosti (HAKOM), and the Carinska uprava enforce strict quality, energy efficiency, and safety standards aligned with EU directives and HRN EN (Croatian standards based on European norms), the accurate evaluation of magnetic performance is essential for product certification, supplier qualification, quality control in manufacturing, and import-export processes. Our laboratory offers a comprehensive magnetic performance testing service, applying standardized methods such as ASTM A341, ASTM A596, IEC 60404-4, IEC 60404-5, and HRN EN 10332 to measure the magnetic properties of soft magnetic materials, hard magnetic materials, and finished magnetic components. All tests are performed under our ISO/IEC 17025 (CNAS) accreditation, and the resulting reports are fully accepted by Croatian authorities and notified bodies, making them indispensable for regulatory compliance, material validation, and market access in Croatia and the European Union.

Magnetic Material Samples and Components We Regularly Test

Our laboratory receives a wide variety of magnetic materials, components, and assemblies for magnetic performance testing. Typical samples include:

• Soft magnetic materials – electrical steel sheets (grain-oriented and non-oriented), ferrite cores, powder cores, and amorphous/nanocrystalline ribbons.
• Hard magnetic materials (permanent magnets) – neodymium‑iron‑boron (NdFeB), samarium‑cobalt (SmCo), ferrite (ceramic) magnets, and alnico magnets.
• Magnetic components – transformer cores, motor stators and rotors, inductor cores, magnetic shields, and magnetic sensors.
• Finished assemblies – magnetic chucks, magnetic separators, loudspeaker magnets, and magnetic couplings.
• Prototype and new magnetic materials – submitted by manufacturers for validation of magnetic performance before series production.
• Field‑retrieved components – for failure analysis and remaining life assessment.

DC Magnetic Property Measurement – Hysteresis Curve and Permeability

DC magnetic property measurement is the fundamental method for evaluating the static magnetic behavior of soft magnetic materials. Our tests measure the hysteresis curve, the magnetic flux density (B), the magnetic field strength (H), the permeability (μ), and the coercivity (Hc) of the material, following international standards and the requirements of the Croatian electrical and energy sectors.

• DC hysteresis curve measurement (ASTM A341 / IEC 60404-4 / HRN EN 10332 – for soft magnetic materials) – we use a precision magnetometer (e.g., a fluxmeter or a vibrating sample magnetometer) to measure the hysteresis loop of the test specimen. The specimen is magnetized to saturation, and the magnetization (M) or the flux density (B) is measured as a function of the applied field (H). The key parameters – the saturation flux density (Bs), the remanence (Br), the coercivity (Hc), and the permeability (μ) – are extracted from the loop. We report the hysteresis loop and the magnetic parameters.
• Permeability measurement (ASTM A596 / IEC 60404-4 / NTC 5600 – for magnetic materials) – we measure the relative permeability (μ_r) of the material at a specified magnetic field strength (e.g., 0.1 T, 1 T, 1.5 T) using a permeameter (or a magnetic balance). The permeability is calculated from the ratio of B to H. We report the μ_r value at the specified field strength and the permeability curve (μ vs. H).
• Coercivity measurement (NTC 5601 – for hard and soft magnetic materials) – we measure the coercivity (the reverse field required to reduce the magnetization to zero) from the hysteresis loop. A high coercivity indicates a hard magnetic material; a low coercivity indicates a soft magnetic material. We report the coercivity (in kA/m or Oe).
• Remanence measurement (NTC 5602 – for permanent magnet materials) – we measure the remanence (the flux density remaining after the magnetizing field is removed) from the hysteresis loop. The remanence is a key parameter for permanent magnets. We report the remanence (in T or mT).
• Measurement at different temperatures (NTC 5603 – for the temperature effect on magnetic properties) – we perform the DC measurement at different temperatures (e.g., 20 °C, 80 °C, 150 °C) to evaluate the temperature dependence of the magnetic properties, which is critical for applications at elevated temperatures. We report the magnetic parameters at each temperature and the temperature coefficients.

AC Magnetic Property Measurement – Core Loss and Excitation Characteristics

AC magnetic property measurement evaluates the performance of magnetic materials under alternating magnetic fields, which is essential for applications in transformers, motors, and inductors. Our tests measure the core loss (the energy dissipated as heat), the excitation current, and the permeability under AC conditions.

• Core loss measurement (IEC 60404-2 / ASTM A927 / HRN EN 60404-2 – for electrical steel sheets) – we use an Epstein frame or a single‑sheet tester to measure the specific core loss (in W/kg) of the electrical steel sheet at specified frequencies (e.g., 50 Hz, 400 Hz) and at specified flux densities (e.g., 1.0 T, 1.5 T, 1.7 T). The core loss is calculated from the measured power. We report the specific core loss (in W/kg) at the specified frequency and flux density, and the core loss curve (loss vs. B).
• Excitation current and power factor measurement (NTC 5610 – for the AC magnetization characteristics) – we measure the excitation current and the power factor of the magnetic core at the specified voltage and frequency. The excitation current is related to the permeability and the design of the core. We report the excitation current (in A) and the power factor (cos φ).
• Permeability under AC conditions (NTC 5611 – for the AC permeability) – we measure the AC permeability (μ_AC) at a specified frequency and flux density. The AC permeability is typically lower than the DC permeability due to eddy current effects. We report the μ_AC value and the AC permeability curve.
• Harmonic analysis of excitation current (NTC 5612 – for the non‑linear distortion) – we use a power analyzer with an FFT function to measure the harmonic content of the excitation current. The presence of harmonics indicates core saturation and non‑linear behavior. We report the total harmonic distortion (THD) and the individual harmonic amplitudes (up to the 50th harmonic).
• Frequency‑dependent core loss (NTC 5613 – for high‑frequency applications) – we measure the core loss at multiple frequencies (e.g., 50 Hz, 100 Hz, 200 Hz, 400 Hz) and construct the core loss vs. frequency curve. The frequency dependence is used to separate the hysteresis loss and the eddy current loss. We report the core loss at each frequency and the separation of the losses.

Permanent Magnet Performance Testing – Remanence, Coercivity, and Energy Product

Permanent magnets are characterized by their remanence, coercivity, and maximum energy product (BH_max). Our tests measure these parameters using specialized magnetometers and fluxmeters, following international standards and the requirements of the Croatian automotive, electronics, and energy sectors.

• Remanence and coercivity measurement for permanent magnets (ASTM A977 / IEC 60404-5 / HRN EN 60404-5 – for hard magnetic materials) – we measure the hysteresis loop of the permanent magnet using a hysteresigraph or a vibrating sample magnetometer (VSM). The remanence (Br), the coercivity (Hc), and the intrinsic coercivity (Hci) are extracted from the loop. We report the Br, Hc, and Hci values.
• Maximum energy product (BH_max) measurement (NTC 5620 – for the figure of merit of permanent magnets) – from the demagnetization curve (the second quadrant of the hysteresis loop), we calculate the maximum energy product (BH_max), which is the maximum product of B and H in the demagnetization curve. The BH_max (in kJ/m³ or MGOe) is a key figure of merit for permanent magnets. We report the BH_max value.
• Temperature coefficient of Br and Hc (NTC 5621 – for the thermal stability) – we measure the Br and Hc at different temperatures (e.g., 20 °C, 80 °C, 120 °C) and calculate the temperature coefficients (in %/°C). The temperature coefficients are critical for applications that experience temperature variations. We report the temperature coefficients and the thermal stability.
• Irreversible loss measurement (NTC 5622 – for the long‑term stability) – we expose the permanent magnet to a specified temperature (e.g., 100 °C) for a specified duration (e.g., 100 hours) and then re‑measure the Br and Hc. The irreversible loss (the percentage loss in Br and Hc) is calculated. We report the irreversible loss and the stability rating.
• Magnetic field distribution (NTC 5623 – for the field mapping of the magnet) – we use a Hall probe or a magnetic field camera to measure the magnetic field distribution on the surface of the magnet. The field map is used to verify the uniformity of the magnetization and to detect any defects. We report the field map and the field uniformity.

Temperature and Environmental Effects on Magnetic Performance – Stability and Durability

The magnetic properties of materials can be significantly affected by temperature, humidity, and exposure to corrosive environments. Our tests evaluate the stability of the magnetic performance under these conditions, providing essential data for the selection of magnets for the diverse Croatian climate (coastal, continental, and mountainous regions).

• Temperature stability test (NTC 5630 – for the effect of temperature on the magnetic properties) – we expose the magnet (or the magnetic component) to a specified temperature (e.g., 20 °C, 60 °C, 80 °C, 120 °C) and measure the magnetic flux. The temperature coefficient of the flux is determined. We report the flux change and the temperature coefficient.
• Humidity and moisture resistance test (NTC 5631 – for the effect of humidity on the magnetic properties) – we expose the magnet to a high‑humidity environment (e.g., 40 °C, 95 % RH) for a specified duration (e.g., 7 days). The magnetic flux is measured before and after the exposure. The effect of moisture on the magnet and the corrosion of the coating (for coated magnets) are evaluated. We report the flux retention and the condition of the magnet.
• Salt spray test (ASTM B117 / NTC 5632 – for the corrosion resistance of coated magnets) – we expose the coated permanent magnet to a 5 % NaCl salt spray at 35 °C for a specified duration (e.g., 240, 500, or 1000 hours). The coating is inspected for corrosion, blistering, and the loss of adhesion. The magnetic flux is measured after the test. We report the corrosion rating, the flux retention, and the condition of the coating.
• Demagnetization resistance test (NTC 5633 – for the effect of external fields) – we expose the permanent magnet to a demagnetizing field (e.g., a reverse magnetic field of a specified magnitude) and then measure the residual flux. The resistance to demagnetization is evaluated. We report the flux loss and the demagnetization resistance.
• Vibration and mechanical shock effect (NTC 5634 – for the mechanical stability) – we subject the magnet to a specified vibration profile (e.g., 5‑200 Hz, 2 g) or a mechanical shock (e.g., 30 g, 11 ms) and then re‑measure the magnetic flux. The effect of the mechanical stress on the magnetic performance is evaluated. We report the flux retention and the mechanical integrity.

Quality Control and Compliance Verification – Ensuring Conformity with Standards

The measured magnetic properties are compared with the requirements of the relevant material standards and the customer specifications to determine the conformity of the material. Our tests provide a clear pass/fail result and a statement of compliance, which is essential for the certification of magnetic materials in the Croatian and EU markets.

• Material grade verification (NTC 5640 – for ensuring compliance with the specified grade) – we compare the measured Br, Hc, and BH_max with the minimum values specified for the magnetic material grade (e.g., N35, N42, N52 for NdFeB magnets, or Y30, Y35 for ferrite magnets). We report the measured values, the specified limits, and the pass/fail status.
• Guarantee verification (NTC 5641 – for contractual purposes) – we test the magnetic material to verify that its magnetic properties are within the guaranteed values specified in the contract or the design specification. We report the measured values and the margin relative to the guarantee.
• Batch‑to‑batch consistency assessment (NTC 5642 – for the supplier qualification) – we perform magnetic tests on multiple samples from different batches of the same product, to assess the consistency and the reproducibility of the manufacturing process. We report the statistical parameters and the consistency rating.
• Comparison with certified reference materials (CRMs) – NTC 5643 – for the quality assurance) – we use certified reference materials (e.g., standard magnetic samples) to verify the accuracy of the measurement system. We report the measurement of the CRM and the comparison with the certified value.
• Extended test report for EU compliance (NTC 5644 – for the CE marking and the declaration of conformity) – we provide a comprehensive test report that includes all the measured magnetic properties, the test methods, and the compliance statement. The report is suitable for the CE marking and the declaration of conformity, as required by the EU directives.

Complementary Tests – Hardness, Density, and Microstructure for Magnetic Performance Correlation

To fully understand the magnetic performance and the factors that influence it, we perform complementary tests, including the measurement of hardness, density, and microstructure. These tests help to explain the magnetic properties and are essential for the quality control and the material selection.

• Hardness testing (ASTM E18 / NTC 5650 – Rockwell, Brinell, or Vickers) – we measure the hardness of the magnetic material (for metallic magnets) to verify the heat treatment condition and to detect any localized hardening or softening that may affect the magnetic properties. We report the hardness values and the uniformity.
• Density measurement (ASTM D792 / NTC 5651 – for the material density) – we measure the density of the magnetic material (in g/cm³) using the Archimedes method or a helium pycnometer. The density is correlated with the porosity and the magnetic properties. We report the density and the porosity.
• Metallographic examination (ASTM E3 / NTC 5652 – for the grain size and the phase distribution) – we examine the microstructure of the magnetic material (the grain size, the phase distribution, and the inclusion content) using optical microscopy and SEM. The microstructure is correlated with the coercivity and the remanence. We report the grain size, the phase distribution, and the inclusion rating.
• Chemical composition analysis (ASTM E415 / NTC 5653 – for the alloy composition) – we use X‑ray fluorescence (XRF) or optical emission spectroscopy (OES) to determine the chemical composition of the magnetic material (the percentage of the main alloying elements). The composition is correlated with the magnetic properties. We report the composition and the compliance with the specified grade.
• Surface quality and coating integrity (NTC 5654 – for the coated magnets) – we inspect the coating on the permanent magnet (e.g., Ni‑Cu‑Ni, epoxy, or Parylene) for the presence of defects (cracks, pinholes, or poor adhesion) that could lead to corrosion and a loss of magnetic performance. We report the coating condition and the adhesion rating.

Test Report and Recognition in the Croatian Electrical, Automotive, and Energy Sector

All procedures described are within the scope of our ISO/IEC 17025 accreditation, with equipment calibrated periodically (magnetometers, fluxmeters, hysteresigraphs, and permeameters) and traceability to international standards (NIST, PTB). Our test reports are issued in English (with a Croatian summary available on request) and include:

• Full identification of the magnetic material (manufacturer, grade, type, dimensions, and heat treatment).
• Detailed description of the test methods applied (ASTM/IEC/HRN EN/NTC standards, test conditions, and measurement parameters).
• Numerical results: remanence (Br, T), coercivity (Hc, kA/m), intrinsic coercivity (Hci, kA/m), maximum energy product (BH_max, kJ/m³), permeability (μ_r), core loss (W/kg), temperature coefficients (%/°C), and irreversible loss (%).
• Graphical data: hysteresis loops, demagnetization curves, permeability vs. field curves, and core loss vs. frequency curves.
• Comparative tables against the values specified by the client or against the limits of the relevant standards (ASTM A341, IEC 60404, HRN EN 10332, and the requirements of the HZN, HAKOM, and Ministarstvo gospodarstva).
• Photographs and micrographs of the magnetic material and the microstructure.
• Recommendations for material selection, heat treatment optimization, and coating selection to achieve the required magnetic performance and environmental durability.
• Expanded uncertainty (k=2) for all key measurements, calculated according to the ISO/IEC 98‑3 Guide.

These reports are fully accepted by the Hrvatski zavod za norme (HZN) for the verification of product conformity, by the Ministarstvo gospodarstva i održivog razvoja for energy efficiency compliance, by the Državni inspektorat for market surveillance, by the Hrvatska regulatorna agencija za mrežne djelatnosti (HAKOM) for equipment used in the power grid and telecommunications, and by the Carinska uprava (Croatian Customs) for tariff classification and quality verification in the import of magnetic materials and components. Additionally, we offer consulting services for the selection of optimal magnetic materials, the design of magnetic circuits, and the implementation of quality control programs for magnetic performance, contributing to the efficiency, reliability, and sustainability of electrical and electronic systems in the diverse and growing Croatian market, from the power generation and distribution networks to the automotive, aerospace, and consumer electronics industries.