In simple terms: alternating current repeatedly magnetizes the magnetic core, and the material’s resistance to “turning back to its original state” is what we call hysteresis loss. The greater this resistance, the more energy is wasted in cycling back and forth, and the more heat is generated; therefore, soft magnetic materials are designed to have low coercivity.

Premium high‑end materials (for automotive OBCs, high‑power charging stations, and high‑precision current transformers): coercivity ≤ 2 A/m, with uniform grain structure and precisely controlled annealing, resulting in extremely low high‑frequency losses.

General‑purpose compliance materials (standard switching power supplies, EMI filters): coercivity 2–4 A/m, meeting all grade‑specific limit requirements of GB/T 19345.2‑2017; nonconforming‑product alert: coercivity > 4 A/m exceeds the national standard’s upper acceptance limit.

Hc > 10 A/m typically indicates annealing defects, excessive tape stress, or coarse grain structure, leading to a sharp increase in core losses and excessive temperature rise; such material must not be used for mass‑produced components.

Note: According to GB/T 19345.2-2017, the coercivity of qualified nanocrystalline materials shall not exceed 4 A/m, while high‑quality finished products are typically kept below 2 A/m.

In summary: When comparing parts of the same specification and from the same batch, lower coercivity indicates a fundamentally better base material.

Permeability can be understood as the ease with which magnetic flux lines pass through a material. The higher the value, the fewer turns are needed to achieve a given inductance, allowing for a smaller magnetic core; however, blindly pursuing excessively high values can easily lead to pitfalls.

High‑end, dedicated to common‑mode and current transformers: initial permeability of 80,000–150,000 (Note: this ultra‑high‑permeability grade requires special annealing and custom fabrication; it is not suitable for standard mass production of conventional product lines). It exhibits low high‑frequency attenuation and strong EMI suppression, making it the preferred choice for photovoltaic inverters, 800‑V automotive‑grade power supplies, and precision current transformers.

Economy‑grade general‑purpose material: initial permeability 50,000–80,000. Offers excellent cost performance and is well suited for small to medium‑power conventional power supplies.

Anti-bias filter material: initial permeability 5,000–30,000. Specifically designed to withstand high DC bias and prevent magnetic saturation.

Key points to avoid pitfalls:

Some manufacturers falsely inflate the magnetic permeability rating: while the low-frequency performance looks impressive on paper, it plummets as soon as you reach the high frequencies of 50 kHz or 100 kHz.

A magnetic permeability variation exceeding 15% within the same batch indicates that the manufacturer’s annealing process is poorly controlled, resulting in extremely poor consistency.

In circuits with a large DC bias, an excessively high permeability can easily lead to magnetic saturation; therefore, higher is not always better.

Core losses refer to the heat generated within the magnetic core during operation; the higher the frequency, the more pronounced the advantages of nanocrystalline materials over ferrite and silicon steel. This is also the parameter that customers most readily perceive when the component is mounted in a device.

Top‑grade premium material: Hc ≤ 2 A/m + permeability of 80,000–150,000 (or a specific low‑permeability grade resistant to bias) + minimal frequency‑dependent loss + relatively low high‑frequency losses—ideal for high‑end new‑energy applications.

General‑purpose compliance material: Hc 2–4 A/m + permeability 50,000–80,000 + excellent batch-to-batch consistency + moderate core losses; ideal for standard cost‑reduction substitutions.

Beware of defective products: if the coercivity exceeds 4 A/m, the permeability fluctuates significantly, or the high-frequency loss is abnormally high, avoid placing large orders—even at low prices.

Focusing solely on permeability: Pursuing ultra‑high permeability at all costs degrades bias‑field resistance and severely limits the range of applicable applications.

Focus only on price, not specifications: Low‑priced materials often undergo annealing‑induced shrinkage and exhibit uncontrolled coercivity, leading to higher after‑sales costs down the line.

Focus solely on low-frequency parameters: the nanocrystalline core excels in the tens of kilohertz to megahertz range; always verify loss data at the actual operating frequency (never discuss parameters without considering frequency and magnetic flux density).

Under identical specifications and test conditions, a straightforward assessment of nanocrystal quality can be made without complex analysis. , remember this core logic: The lower the coercivity, the better the material; magnetic permeability reflects stability rather than peak values; and the lower the high-frequency losses, the more effectively heat is managed. By comparing the results against the reference range, you can avoid low‑price, substandard pitfalls and feel more confident when selecting a model and negotiating the price.