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Dysprosium Substitutes: How Industry Reduces Dy Risk

Dysprosium (Dy) is used mainly to solve one problem in NdFeB permanent magnets: keeping coercivity high as temperature rises, so magnets resist demagnetization in hot-running motors and generators.

The downside is real: adding Dy can reduce remanence (Br), which can cut magnet strength for a given size, and Dy is supply-chain sensitive.

Back to Dysprosium Overview

What "substitutes" really means for dysprosium

In practice, "substituting dysprosium" usually means one of five strategies:

1. Use less Dy in the same NdFeB magnet (Dy-thrifting)

2. Replace Dy with another heavy rare earth (usually terbium, sometimes others)

3. Replace NdFeB with a different magnet type (SmCo, ferrite, Alnico)

4. Use a motor design that needs fewer or no rare earth magnets (induction, reluctance, wound-field)

5. Lower the temperature requirement so the magnet needs less Dy (cooling, design, duty cycle)

Most real-world "Dy substitution" is a mix of 1 + 5, not a clean one-for-one replacement.

1

Dy-thrifting inside NdFeB magnets (the main path)

Grain boundary diffusion and related approaches

A common industrial direction is to put heavy rare earths where they do the most good: near grain boundaries, rather than uniformly throughout the magnet. This can improve coercivity while using far less Dy than older "bulk doping" approaches, and it can reduce the remanence penalty.

Why this matters for substitution:

It does not remove Dy from the system, but it can cut Dy per magnet enough that supply risk drops materially.

Dy-free or Dy-lean magnet grades

Magnet makers also use:

  • • Improved microstructure control, grain refinement, and boundary phase engineering
  • • Grade selection and magnet geometry optimization
  • • Tailored coercivity targets based on actual thermal load rather than worst-case assumptions

The point is to stop over-specifying Dy "just in case".

2

Replacing dysprosium with terbium

Terbium (Tb) can also boost coercivity and high-temperature stability in NdFeB magnets. But Tb is typically even more constrained and expensive, so "Tb substitution" is often a technical option with a tougher procurement story.

Works technically, worse for supply risk

Many Dy-reduction strategies are framed as reducing "heavy rare earths" overall (Dy + Tb), not shifting from one to the other.

3

Switching to different magnet chemistries

Samarium-cobalt magnets (SmCo₅, Sm₂Co₁₇)

SmCo magnets handle high temperatures and corrosion better than NdFeB and usually do not rely on dysprosium. They are a real substitute in high-temperature, high-reliability applications.

Tradeoffs:

  • • Higher cost and different supply risks (notably cobalt)
  • • Different manufacturability and magnet properties compared with NdFeB

Where SmCo wins:

Aerospace, defense, downhole, high-temp industrial, niche motor designs that justify cost

Ferrite magnets (strontium ferrite)

Ferrite magnets are abundant and cheap, and they avoid rare earths entirely. They can substitute in designs where you can accept lower energy product and larger magnet volume.

Tradeoffs:

  • • Larger and heavier motor designs to achieve similar torque density
  • • Performance limits in compact high-power systems

Alnico magnets

Alnico can tolerate high temperatures and has good stability, but coercivity is relatively low compared with modern rare-earth magnets, so applications are narrower.

Tradeoffs:

  • • Demagnetization risk in many traction-motor duty cycles
  • • Limited fit for compact high-torque designs
4

Magnet-free or reduced-rare-earth motor designs

If you want a real Dy substitute story, motor topology is where it happens. Several motor types avoid permanent magnets:

Induction motors (asynchronous)

No permanent magnets. Robust and proven. The tradeoff is typically lower efficiency and power density versus high-end permanent magnet designs, depending on the duty cycle and controls.

Switched reluctance motors (SRM)

No magnets, simple rotor, strong high-speed potential. Tradeoffs include noise/vibration control challenges and torque ripple mitigation (engineering problem, not magic).

Synchronous reluctance and PM-assisted reluctance variants

Can reduce magnet content substantially, sometimes using small magnets mainly for control and efficiency rather than torque.

Wound-field synchronous motors (electrically excited)

Replace permanent magnet excitation with copper windings and control systems. This can cut rare earth dependence, at the cost of rotor complexity and control demands.

This is not theoretical: automakers are actively pursuing "rare-earth-free" traction motor strategies because supply concentration risk is a business problem.

5

Designing the heat problem away (the underrated substitute)

Because Dy is mostly a temperature insurance policy, reducing magnet operating temperature can reduce Dy content.

Common levers:

  • • Improved cooling (oil cooling, better thermal pathways)
  • • Inverter and control strategies that reduce losses and hot spots
  • • Motor geometry that reduces peak demagnetizing fields
  • • Duty-cycle specific design (stop designing every motor for the worst possible abuse case)

This approach stacks with Dy-thrifting and often delivers the biggest "Dy reduction per dollar".

Quick decision map: which substitute path fits which constraint?

If the goal is "keep NdFeB performance but reduce Dy risk"

  • → Grain boundary diffusion and Dy-thrifting
  • → Better cooling and thermal design

If the goal is "avoid heavy rare earths entirely"

  • → Magnet-free motor designs (SRM, induction, wound-field)
  • → Ferrite-based designs where size/weight is acceptable

If the goal is "high temperature, high reliability, cost is secondary"

  • → SmCo magnets

What substitution does to the supply chain

Reducing dysprosium intensity does not automatically de-risk the chain if you still rely on NdFeB magnets and concentrated magnet manufacturing.

It primarily reduces exposure to heavy rare earth units, which are among the most fragile parts of the magnet feedstock story.

The structural concentration angle is covered here: Dysprosium supply chain

Dysprosium Substitutes FAQ

Is there a true one-for-one replacement for dysprosium in NdFeB magnets?

Not cleanly. The closest practical replacement is terbium in some magnet engineering approaches, but it tends to be even more supply constrained.

What's the most common real-world way to cut dysprosium usage?

Dy-thrifting, especially grain boundary diffusion style approaches, combined with better thermal design so the magnet does not need as much high-temperature coercivity margin.

Are "rare-earth-free" EV motors real?

Yes. Induction and reluctance-based designs avoid rare earth magnets, and manufacturers continue to develop and commercialize them, trading off efficiency, noise, and packaging depending on the platform.

Does recycling reduce the need for substitutes?

Recycling helps, but it does not eliminate the need for substitution because recycling feedstock is limited in the near term and still needs processing and qualification. The recycling side is here: dysprosium recycling.