Synergy in High-Performance Magnetic Materials
In modern power electronics and drive technology, subtle differences in microstructure can have a significant impact on the overall efficiency of a system. The strategic partnership between VACUUMSCHMELZE (VAC) and SEKELS GmbH brings together two key areas of expertise: state-of-the-art metallurgical knowledge and exceptional, application-specific finishing. VAC is a leading innovator in the field of high-performance soft and hard magnetic materials. SEKELS transforms these materials into process-ready components by offering specialized consultancy services, a comprehensive inventory and precise manufacturing solutions. This gives developers in the fields of e-mobility and automation a significant competitive advantage. It bridges the gap between theoretical material properties and industrial production readiness.
Strategic alliance for power electronics and drive technology
This collaboration creates synergies that extend well beyond the scope of a traditional distribution model. This partnership is based on the following strategic pillars:
- Technology leadership (VAC): Access to VAC’s high-performance alloys, whose high purity and precisely adjusted composition place them among the strongest materials in terms of saturation polarization and energy product.
- Application and Logistics Expertise (SEKELS): Comprehensive support from magnetic field simulation and design to series delivery. An extensive inventory of NiFe and CoFe alloys in various sizes ensures a stable supply chain, even in volatile market conditions.
- System solutions and measurement technology: Integration of material expertise into complex magnet systems and shielding, complemented by highly precise measurement technology such as the MFA-110 system for high-resolution magnetic field analysis.
Accelerated Market Introduction Through Process Integration
Close integration significantly shortens the time to market for end customers. Rather than undergoing lengthy qualification processes with separate manufacturers and processors, customers receive coordinated solutions. These solutions are optimized for the final manufacturing steps. The superior quality of VAC melts is the basis for this optimization. It only reaches its full technological potential through metallurgically correct further processing.
SEKELS' manufacturing depth and process technology refinement
High-performance alloys based on nickel-iron (NiFe) or cobalt-iron (CoFe) achieve their exceptional magnetic properties not only through their chemical composition, but also through their thermomechanical processing.
SEKELS offers specialized production depth in this area:
- Slitting and cutting to size: Precision slitting and cutting of strip (e.g., PERMENORM in thicknesses from 0.025 to 0.1 mm) into process-ready coils, precisely matched to customer-specific winding or stamping processes.
- Composite Systems & Adhesive Technology: To minimize eddy current losses in high-frequency applications, SEKELS manufactures bonded sheet packages and laminated assemblies that combine mechanical integrity with electrical insulation.
- Thermal Treatment (final annealing): Soft magnetic NiFe and CoFe alloys (e.g., MUMETALL®, PERMENORM®, VACOFLUX®, VACODUR®) are typically supplied in a mechanically hardened or deep-drawable condition. Their magnetic properties are only fully developed after final annealing. SEKELS conducts this process in stationary hydrogen furnaces at temperatures of up to 1,150°C according to manufacturer or customer specifications. Since the material becomes mechanically soft during this process, and the demanding parameters involved are usually beyond what standard hardening shops can reproduce, SEKELS provides the specialized furnace technology and expertise this requires.
Real efficiency gains through material-appropriate processing
There is a significant contrast between the cold-rolled delivery state and the magnetically optimized end form. While the material is magnetically unremarkable in its original state, with high coercivity and low permeability, precise heat treatment is essential for significantly improving its performance. Without this specialized knowledge, the physical superiority of VAC materials would go unused in real applications.
Innovations in soft magnetic materials: VACODUR Max and PERMENORM
Modern high-speed motors demand materials that combine extreme saturation polarization with high mechanical strength — a challenge that pushes conventional electrical steel to its limits. SEKELS processes two materials from VACUUMSCHMELZE’s current portfolio: VACODUR Max, according to VAC its most recent Permendur grade, and PERMENORM 5000 Z, a tailored variant of the PERMENORM 5000 alloy family, for applications ranging from high-performance drivetrains to wound cores with a square hysteresis loop.
VACODUR Max: metallurgical flexibility in the drivetrain
VACODUR Max (49% Co, 49% Fe, 1% V + Nb) reaches a saturation polarization of 2.35 T (ASTM standard: 2.30 T) while allowing its yield strength to be adjusted: through heat treatment, primarily the annealing temperature, 150 to 400 MPa can be set. This makes it possible to produce a magnetically optimized stator and a mechanically optimized rotor with defined yield strength from the same strip. Typical values for 0.1 mm strip:
| Property | Stator grade | Rotor grade |
|---|---|---|
| Saturation polarization JS | 2.35 T | 2.35 T |
| Yield strength Rp0.2 | 150 MPa | 400 MPa |
| Max. permeability µmax | 22,000 | 7,000 |
| Annealing temperature (H2) | 915 °C | 735 °C |
| Annealing time / cooling rate | 6 h / 100–200 K/h | 3 h / 100–200 K/h |
Source: VAC datasheet VACODUR Max (typical values for 0.1 mm strip)
Material efficiency through “stator and rotor from a single strip”
With VACODUR Max, stator and rotor laminations can be stamped from the same strip. Only the different heat treatment at SEKELS gives the stator its maximum permeability, while the rotor develops the strength required for the high rotational speeds. This enables particularly efficient use of material.
PERMENORM 5000 Z: square hysteresis loop for wound cores
PERMENORM 5000 Z (47.5% Ni, balance Fe) is a tailored variant of the PERMENORM 5000 NiFe alloy family. It is characterized by a high remanence magnetization: after a specific final heat treatment, it shows a distinct rectangular hysteresis loop. For strip wound cores, the ratio of remanence to peak magnetization is typically BR / B1 ≥ 0.95. The parameters of the final heat treatment are often application-specific and must be carefully adjusted to the desired properties. PERMENORM 5000 Z is supplied as strip material (0.025–0.1 mm); according to the datasheet, typical applications are laminated cores and wound cores.
Sustainable permanent magnets: the VACODYM generation
Alongside soft magnetic materials, permanent magnets (NdFeB) are also in focus. Dependence on heavy rare earths (HRE) such as terbium (Tb) and dysprosium (Dy) calls for new, resilient supply chains. VAC addresses this strategic need with two alloy series:
- VACODYM 90X — completely terbium-free, with magnetic properties comparable to or even better than the proven VACODYM 80X series. Its grade VACODYM 902 TP goes further: it is entirely free of heavy rare earths and reaches a remanence of Br ≥ 1.40 T and a coercivity of HcJ ≥ 1,190 kA/m at room temperature.
- VACODYM 91X — reduced Tb and Dy content, the highest magnetic properties thanks to optimized raw material utilization, and greater cost stability.
Technological sovereignty through a western supply chain
For VACODYM 902 TP, VAC cites a 100% license-free supply chain from mine to magnet, with production entirely in the western world, and describes the material as a geopolitically independent alternative to HRE-based solutions. For European and American industries, supply chain security thus becomes a measurable competitive factor, especially in e-mobility and aerospace.
Conclusion: holistic solutions for the electrical engineering of tomorrow
The close integration of VAC's materials expertise with SEKELS' processing and measurement capabilities forms the foundation for the next generation of highly efficient electrical systems. For engineers and strategic buyers, this translates into three core advantages:
- Technological sovereignty: Access to permanent magnets with reduced or no heavy rare earth content, such as VACODYM 902 TP.
- Process reliability: Validated material properties through heat treatment processes and quality control.
- Performance maximization: High efficiency through the alignment of metallurgical base material and application-specific final form, for example with CoFe alloys such as VACODUR Max.
Future readiness today comes from the symbiosis of sustainable material concepts and local manufacturing know-how. The partnership between VAC and SEKELS is the answer to the growing complexity of global markets and technical requirements.
