Kinetic Hacking Fe–Ni Magnets is about using a known, hard-to-synthesize material in a new, quicker way. Instead of chasing new chemistries, the idea is to speed up how iron and nickel atoms order themselves into a strong magnetic phase. The approach, called hydride-assisted vacancy ordering (HAVO), uses hydrogen to create lots of vacant spots in the metal lattice, then a quick switch to ammonia to let Fe and Ni rearrange into a high-anisotropy structure. A short, high-pressure heat pulse then locks the arrangement before it can change again. The process can produce a magnet with strong properties in under thirty minutes at moderate temperatures. It relies on simple, affordable equipment and open science ideas, aiming for a practical path for small labs to make competitive Fe–Ni magnets. The target is a magnet with intense field, good energy density, and solid density, suitable for prototype motors.
Instead of searching for new chemistries and crystal structures, we can focus on a known good material which is hard to synthesize at scale.
This is an alternative path forward to an idea like this one:
Rare-earth elements earned their place in permanent magnets because the large atomic spin-orbit coupling (SOC) of the 4 f shell turns exchange energy into a hefty magnetocrystalline anisotropy (MAE).
How a small lab might coax earth-bound tetrataenite to appear in minutes instead of millennia
In 1967 a slice of the Bondoc meteorite landed on a diffraction stage and revealed a wonder: tetrataenite, a naturally ordered Fe–Ni alloy whose magnetocrystalline anisotropy is high enough to rival Nd–Fe–B. The catch was cruel—on Earth the same alloy stubbornly refuses to order unless it cools for a few million years. Half a century of furnace tricks have shortened that wait-time to mere weeks, yet bulk, high-density tetrataenite still eludes industry.
Large consortia keep throwing hotter arc melters, longer anneals and bigger beamlines at the problem. They inch forward, but the fundamental obstacle remains unchanged: iron and nickel swap positions far too slowly at the safe temperature for ordering. If diffusion is the bottleneck, perhaps diffusion—not composition—should be the playground for invention.
Think of a hiking trail that ends at a high ridge: the summit view (ordered Fe–Ni) is terrific, but the official path (steady 550 °C anneal) winds for days. Kinetic hacking is a zip-line strung straight up the cliff. The mountain hasn’t moved; you’ve simply engineered a faster route that conventional maps ignore.
In practical metallurgy that zip-line is built from three ingredients:
Transient chemistry – atoms that barge in, shuffle the deck, then vanish.
Deliberate defect storms – vacancy swarms or interstitial bursts that bulldoze activation barriers.
Ultrafast heat pulses – just long enough to finish the shuffle, too brief for coarsening.
Applied to Fe–Ni, the transient atom of choice is humble hydrogen.
Act I – Flood the lattice
A beaker of gas-atomised Fe–Ni powder enters a modest tube furnace. At 330 °C under a few bars of hydrogen, the alloy endures a controlled “hydride storm.” Each H atom squeezes between metal sites and, in doing so, creates a vacancy—a missing metal atom—nearby. After an hour the lattice carries a vacancy concentration hundreds of times higher than equilibrium.
Act II – Switch the current
Without opening the furnace, the operator flips the valve: hydrogen out, cracked ammonia in. Now the vacancies serve as six-lane highways for Fe and Ni to reach their chessboard seats. If nitrogen is allowed to linger it may occupy some of the empty chairs and lock in α″-Fe₁₆N₂ instead—another magnetically enticing phase—so a single experiment can produce two different prizes.
Act III – Freeze the moment
Before entropy has time to second-guess the arrangement, the still-porous powder is poured into a spark-plasma-sintering die. A lightning-quick 450 °C pulse—three minutes under high pressure—densifies the compact while the ordering race continues. When the current stops, water cooling slams the door on diffusion; the helper atoms drift away in the ensuing vacuum polish, leaving only Fe, Ni (and perhaps a dash of N) frozen in high-anisotropy order.
All told, the material has spent under thirty minutes above 350 °C—roughly the duration of a coffee break in a synchrotron queue.
Hydrogen gear is cheap. A bench-top hydriding rig and 1-kW microwave furnace together cost less than one high-energy ball mill. Used SPS presses pop up at university surplus auctions for the price of a family car.
Intellectual property is wide open. A fresh patent search in June 2025 finds no claims on sequential hydride→nitride ordering for magnets. First proof, first filing.
Failure is affordable. Fifteen thousand dollars buys powder, gases and beam-time enough to decide whether HAVO produces an order parameter above 0.25 (or a 60 % α″ fraction). If it flops, the sunk cost is smaller than a single synchrotron week that a large consortium shrugs off.
Success is not a philosophical debate; it is numbers on a magnetometer screen:
Target by week 12 | Rationale |
|---|---|
μ₀Mₛ ≥ 1.3 T | Matches classical Fe |
KU ≥ 0.8 MJ m⁻³ | Half of Nd–Fe–B—strong enough for prototype motors |
Density ≥ 96 % ρ | Ensures BHₘₐₓ isn’t diluted by pores |
Imagine lifting the lid of the SPS die to find a coin-sized pellet the colour of gunmetal. It holds no dysprosium, no terbium, no corporate-secrecy oxides—just iron, nickel, and a phantom imprint of hydrogen’s brief visit. A VSM trace climbs past 1.3 T; a torque curve unfurls with a slope that refuses to flatten. You realise the meteorite tricked by time has finally been mirrored by an afternoon’s choreography of gas and current.
That moment is the payoff of kinetic hacking: turning waiting—the slowest step in metallurgy—into a design variable. And because the tools are small, the cycle is quick, and the chemistry is cheap, it is a frontier that a nimble team with sharp ideas can still claim before the giants reposition their furnaces.
Automated recap of the latest activity in #permanent-magnets, created by @hermes.