Aerospace’s Rare Earth Problem Is a Physics Issue, Not a Policy One

A modern jet engine survives temperatures north of 1,300 degrees Celsius because a thin ceramic coating on its turbine blades refuses to fail. That coating works because it is doped with rare earth elements, and those elements are refined almost entirely by a single country at rates of 95 percent or higher.

This is not, at its root, a supply chain vulnerability story. It is a physics problem, and the country holding the answer is China.

The dependency runs far deeper than mining. It runs through separation, refining, and the permanent magnets that drive actuators and guidance systems. Chinese export restrictions effective 1 December 2025 moved this from a latent risk to an active constraint on Western aerospace and defence procurement, and the industry’s response now includes revisiting ceramic formulations abandoned four decades ago.

What follows separates the credible near-term moves from the decade-scale structural problem that cannot be rushed.

China does not just mine rare earths. It controls what happens to them afterward.

Start with the mine, where China’s position looks strong but not absolute. In 2024, global rare earth mine production reached roughly 390,000 tonnes, and China accounted for about 270,000 tonnes, or 69 percent of the total. Significant, certainly. But an allied nation could plausibly close that gap with new mines.

The next step is where the picture changes. China refined approximately 215,000 tonnes in 2024, close to 90 percent of global refined output. Mining a rare earth deposit and separating it into usable oxides are entirely different industrial capabilities, and the West has largely ceded the second one.

For aerospace, the concentration tightens further. China produces roughly 95 percent of refined yttrium and 85 percent of refined scandium, the elements that make high-temperature coatings function.

For samarium, gadolinium, terbium, dysprosium, and lutetium, China controls 97-98 percent of refined output. For the heavy rare earths that aerospace depends on most, the refining chokepoint is very nearly absolute.

The final layer is magnets. Neodymium, praseodymium, dysprosium, and terbium drive the motors and actuators inside engines and guidance systems, and here China holds around 60 percent of mining, 91 percent of refining, and 94 percent of sintered permanent magnet production.

The gap between the 69 percent mining share and the 90-plus percent refining share is the fact that matters most. A country that mines rare earths but cannot separate them has not reduced its dependency on China at all. For investors, that means mine output alone does not buy supply independence. The value, and the risk, live in the processing steps.

The gap between the 69 percent mining share and the 90-plus percent refining share is the fact that matters most, and the refining bottleneck operates differently from any mining concentration because it reflects decades of accumulated industrial chemistry, not just resource geography.

Why rare earths cannot simply be swapped out of a jet engine

The intuitive assumption is that substitution is an engineering problem waiting for money. Fund the research, run the trials, and rare-earth-free coatings arrive. The chemistry says otherwise.

Above approximately 1,300 degrees Celsius, unmodified zirconia undergoes a phase transformation, the tetragonal-to-monoclinic shift, that cracks the coating and causes it to peel away from the blade. Multi-rare-earth doping in yttria-stabilised zirconia (YSZ) suppresses that transformation. It does so by creating lattice distortions and oxygen vacancies that hold the material stable at temperature.

This is not a marginal performance boost. Rare-earth zirconates such as Gd₂Zr₂O₇ and La₂Zr₂O₇ outperform conventional YSZ on phase stability, on thermal conductivity reduction, and on resistance to CMAS, the molten calcium-magnesium-alumino-silicate ash that attacks coatings during flight.

Rare-earth doping performs several distinct jobs at once inside a turbine coating:

• Thermal phase stability: preventing the transformation that causes delamination above 1,300 degrees Celsius
• CMAS corrosion resistance: withstanding molten ash ingested during operation
• Mechanical toughness: resisting erosion under high-velocity gas flow
• Luminescent diagnostics: enabling sensing layers that monitor internal temperature and detect delamination in real time

That last function has no non-rare-earth equivalent. A coating that cannot report its own condition removes a safety and maintenance tool engineers now rely on.

What the alternatives actually deliver, and where they fall short

Canada’s National Research Council and industry partners are evaluating older zirconium dioxide and non-rare-earth oxides. European producer Oerlikon Metco already sells zirconia coatings modified with magnesium and calcium oxides, formulations rooted in 1970s and 1980s chemistry. Some US coating producers are assessing similar options.

The tell is in where they are being positioned: lower-criticality engine components, not the primary thermal barrier coatings on turbine blades exposed to peak temperature. That placement is the industry’s honest admission that substitution is not viable for the parts that matter most.

Better instrumentation today may allow refinements on those old formulations, but the performance gap is structural, not a measurement problem. Recycling excess coating material has been raised as supplementary relief, and it helps at the margin, but it cannot close a structural deficit.

For investors, this establishes why aerospace-grade rare earth demand is structurally inelastic. The end user cannot engineer around the dependency on the timeline that geopolitics is now imposing.

The policy response is real and well-funded. The timeline is not.

The commitments are substantial and should not be waved away. The One Big Beautiful Bill Act, signed 4 July 2025, directed $2 billion toward National Defence Stockpile critical mineral purchases, $5 billion into an Industrial Base Fund, a $500 million Department of Defence (DoD) credit programme, and $1 billion in Defence Production Act financing. A US-Australia framework on critical minerals followed on 20 October 2025.

The single most consequential move is the DoD’s direct stake in MP Materials.

The DoD took a 15 percent equity stake in MP Materials and guaranteed a price floor of $110 per kilogram for NdPr. Governments do not absorb financial risk at that level unless they have accepted that the market alone will not fix the problem on the required timeline.

MP Materials’ DoD partnership terms confirm the structure of the arrangement: a $400 million preferred stock purchase by the DoD, a 10-year price floor of $110 per kilogram for NdPr oxide, and a commitment for the DoD to purchase 100 percent of magnets produced at the new 10X Facility.

MP Materials produced a record 50,692 tonnes of rare earth oxide concentrate in 2025, about 11.5 percent of global output, and doubled NdPr oxide output to 2,599 tonnes. As a condition of the partnership, it ceased sales to China in Q3 2025.

Lynas Rare Earths delivered the milestone that matters most for aerospace: the first commercial ex-China supply of separated heavy rare earths, with dysprosium oxide shipments starting May 2025 and terbium oxide in June 2025.

Lynas’s milestone on dysprosium and terbium oxide shipments represents the first commercial ex-China separated supply, but its broader heavy rare earth processing capacity depends on multiple facilities moving through construction and permitting in parallel, a complexity the Malaysia development illustrates directly.

The limits sit in the fine print. MP Materials’ heavy separation circuit targets mid-2026 commissioning at just 200 tonnes per year of dysprosium and terbium. Lynas’s Texas plant faces wastewater permitting uncertainty. None of the EU’s 60 Strategic Projects are expected at production scale before 2028.

For investors, the read is specific: government-anchored demand with price floors and equity backstops lowers commercial risk, but only for producers that have already cleared the processing and permitting hurdles.

What history says about how fast supply chains actually change

There is a lived precedent to hold against current optimism. When China cut export quotas in 2010, prices spiked and the world responded with genuine innovation in efficiency and substitution within a few years. Yet China’s underlying dominance survived the decade that followed intact.

That is the calibration point. The last rare earth shock produced real ingenuity and still did not shift the structural position. For the current wave of optimism to end differently, a fundamentally different set of conditions has to hold.

The 2010 quota shock generated real ingenuity and still left ex-China supply chains structurally marginal a decade later, which is the calibration point that separates credible near-term milestones from the broader structural transformation that policy documents tend to conflate with them.

The parallel with electric vehicle materials reinforces the point. Efforts to diversify lithium, cobalt, and nickel away from single-country dominance have moved slowly at the structural level, even with strong demand behind them.

The range of credible projections and what separates them

The honest projections span a wide range:

• Defence independence by 2030 (Neoterra), assuming $20-30 billion in sustained investment
• 50 percent of mining demand met by non-Chinese supply by 2035 (IEA and EU Institute for Security Studies)
• 25 percent of refining and 20 percent of magnet demand by 2035 on the same projections
• 20-30 years for full structural alternatives across allied economies (RareEarthExchanges)

What separates the optimistic case from the structural one is scope. The 2030 defence projection assumes concentrated investment in a narrow procurement category where price floors and government equity already exist. The IEA and EU figures cover the entire industrial economy, where those backstops do not.

Structural diversification requires decade-scale tools: anchor markets, price floors, and staged sourcing quotas ramping from 10 percent in year one to 60 percent by year ten. Those conditions, sustained multi-decade investment, permitting reform, and allied processing capacity online, are not yet fully in place, even with the commitments made so far.

What this means before the supply chain catches up

The aerospace rare earth problem is not a funding gap or an awareness gap. It is a processing and timeline gap, and the two cannot be collapsed into one another. The money is committed; the separation capacity and the permits are not.

Three variables are worth monitoring closely:

1. MP Materials’ heavy separation circuit: whether mid-2026 commissioning holds and output ramps toward the 200 tonne dysprosium and terbium target.
2. Lynas’s Texas permitting: resolution of the wastewater question and what it means for the first US-based heavy rare earth processing capacity.
3. Defence supplier requalification: the pace of re-engineering ahead of the DoD procurement ban that takes effect on 1 January 2027.

That 2027 ban is the clearest forcing function in this analysis. It bars rare earth materials from China, Russia, Iran, and North Korea in defence procurement, and no amount of research funding can defer it. The requalification scramble is happening now.

Investors tracking the three variables above will find our full explainer on rare earth supply chain developments in 2026, which covers MP Materials commissioning progress, magnet price movements, and the procurement policy shifts shaping allied defence procurement through the year.

The IEA and EU project non-Chinese refining supply will cover only about 25 percent of demand by 2035. On a ten-year view, roughly 75 percent remains exposed.

The policy architecture, the DoD equity stake, the price floors, and the combined legislative commitments, is the most durable signal this cycle has produced. It changes the risk calculus for processing-stage investments specifically. Readers who separate what is structurally broken, refining and magnet capacity, from what is genuinely progressing, mining output and first processing milestones, can assess these opportunities with more precision than headline coverage allows.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.

Past performance does not guarantee future results. Financial projections are subject to market conditions and various risk factors, and forward-looking scenarios are speculative and subject to change based on market and policy developments.