Supply risk and cost volatility around dysprosium (Dy) and terbium (Tb) have made heavy rare earth content a design constraint in its own right. This page lists every sintered NdFeB grade BOMATEC can supply today and states, grade by grade, which heavy rare earths it contains. Of the 45 grades currently available, 40 are produced completely free of dysprosium, terbium, holmium and gadolinium — covering remanence from 1.08 to 1.46 T and maximum operating temperatures up to 150 °C. Only the three highest-remanence grades (N-54SH, N-56H, N-56SH) still require dysprosium.

Other grades may already be partially available or under development. If the grade you need is not shown, talk to us — we will advise you on the available options.

How to read this data

Heavy rare earth categories

Heavy rare earth elements (HRE) are added to sintered NdFeB to raise coercivity, which is what allows a magnet to resist demagnetisation at elevated temperature. Dysprosium and terbium are the most effective — and the most exposed to supply and price risk. Holmium and gadolinium are sometimes used as partial substitutes, so "Dy, Tb free" and "Dy, Tb, Ho, Gd free" are not the same statement:

• Dy, Tb, Ho, Gd free — contains none of the four heavy rare earths. The strictest category.
• Dy, Tb, Ho free — gadolinium may be present.
• Dy, Tb free — holmium and/or gadolinium may be present.
• Dy needed — dysprosium is required to reach the specified combination of remanence and coercivity.

Properties

• Br (remanence, T) — the flux density the magnet retains. Higher Br means more force from the same volume.
• HcJ (intrinsic coercivity, kA/m) — resistance to demagnetisation. This is the property HRE additions are used to raise.
• Tmax (°C) — the maximum operating temperature for the grade. It is not a material constant: the working point of your actual geometry matters.
• HcJ at Tmax — the minimum intrinsic coercivity still available at that maximum temperature.

Remanence and coercivity trade against each other. The chart above plots both, so the practical question — can I get the Br and HcJ I need without heavy rare earths? — can be read off directly.

Frequently asked questions

Which NdFeB grades are available without dysprosium and terbium?

42 of the 45 sintered NdFeB grades available today are free of dysprosium and terbium; only N-54SH, N-56H, N-56SH still require dysprosium. 40 of those 42 are additionally free of holmium and gadolinium, which makes them completely free of heavy rare earths. The range covers remanence from 1.08 to 1.46 T and maximum operating temperatures of 80, 100, 120 and 150 °C.

Are heavy-rare-earth-free NdFeB magnets available for 150 °C?

Yes. In the SH class (maximum operating temperature 150 °C, minimum intrinsic coercivity 1592 kA/m), the grades N-35SH through N-52SH are available free of dysprosium, terbium, holmium and gadolinium. N-30SH and N-33SH are available free of dysprosium, terbium and holmium. Above N-52SH, dysprosium is still required. One trade-off applies to N-35SH, N-38SH and N-40SH: in the completely heavy-rare-earth-free version, the minimum intrinsic coercivity retained at 150 °C is 420 kA/m, against 500 kA/m for the dysprosium- and terbium-free version that still contains holmium or gadolinium. Remanence and coercivity at 20 °C are identical in both versions — the difference only appears at the maximum operating temperature.

What is the difference between "Dy, Tb free" and "Dy, Tb, Ho, Gd free"?

Dysprosium and terbium are the heavy rare earths most commonly added to raise coercivity, and the ones most exposed to supply and price risk. Holmium and gadolinium are also heavy rare earths and are sometimes used as partial substitutes. A grade described only as "Dy, Tb free" may therefore still contain holmium or gadolinium. "Dy, Tb, Ho, Gd free" is the strictest category and means no heavy rare earths are used at all. If your specification or your customer's restricted-substance list targets heavy rare earths as a group rather than dysprosium alone, this distinction matters.

Does removing heavy rare earths reduce magnet performance?

At 20 °C, no. For every temperature class up to 150 °C, the same combinations of remanence and intrinsic coercivity are offered heavy-rare-earth free as with heavy rare earths — the chart on this page plots both properties, so this can be verified directly. There are two limits. First, at the very top of the remanence range, N-54SH, N-56H, N-56SH still require dysprosium. Second, for N-35SH, N-38SH and N-40SH the completely heavy-rare-earth-free version retains less coercivity at the maximum operating temperature (420 instead of 500 kA/m at 150 °C), even though its room-temperature properties are unchanged. Whether that matters depends on the working point of your actual geometry, not on the grade alone.

What is the cost difference between HRE-free and HRE-containing magnets?

There is no general answer, and anyone giving you a single percentage is oversimplifying. Heavy rare earths are expensive, so it is a reasonable assumption that leaving them out makes a magnet cheaper. In practice that saving is largely offset: reaching the same coercivity without heavy rare earths requires more demanding processing and tighter process control, and in the higher grades a purer light rare earth feedstock. The net result is that heavy-rare-earth-free grades are often priced comparably to their heavy-rare-earth-containing equivalents, and in some cases can be more expensive. The case for going heavy-rare-earth free is therefore not primarily a cost case — it is about supply security, insulation from dysprosium and terbium price volatility, and meeting customer or regulatory restricted-substance requirements. For an actual figure, the price of a specific part depends on grade, geometry, tolerances, volume and coating as much as on the material, so ask us for a quotation on your part.

Which grades still require dysprosium?

N-54SH, N-56H, N-56SH. These are the highest-remanence variants in the 120 °C and 150 °C classes, where the combination of high remanence and high coercivity cannot yet be reached without dysprosium. Heavy-rare-earth-free versions of these grades are under development and can be shown on this page using the "also show grades under development" filter.

Are corrosion-stable versions of these grades available?

Yes. On request, grades are available as a corrosion-stable type, designated /S. These fulfil a weight loss of less than 5.00 mg/cm² after a pressure cooker test (PCT) at 121 °C, 2.05 bar and 100 % relative humidity for 168 hours. The heavy rare earth content is unaffected by the corrosion-stable variant.

The grade I need is not listed — what now?

The list shows what is confirmed today. Further grades are partially available or under development, and the practical answer often depends on the working point of your actual geometry rather than on the grade alone. Contact BOMATEC with your remanence, coercivity and operating temperature requirement and we will advise on the available options.

Version: March 3, 2026

Material: sintered NdFeB

Values at 20 °C unless stated

Full grade table

Why this table is here: the chart is for people, the table is for machines. Google and AI answer engines such as ChatGPT, Perplexity and Google AI Overviews cannot read values out of a graphic — they read HTML. This table is what makes our grade data findable and quotable, and it is the main reason a web page outperforms the PDF. It stays in the page source whether it is expanded or not.