the.com/mumetal
the alloy that doesn't block magnetic fields so much as politely redirect them elsewhere
means A nickel-iron alloy with extremely high magnetic permeability, used to shield sensitive equipment by guiding magnetic fields around or away from whatever needs protecting.
from The name comes from the Greek letter mu (μ), the standard physics symbol for magnetic permeability — so 'mu-metal' is, quite literally, 'permeability metal.' It was developed in the early 20th century by British researchers seeking to shield telegraph and telephone cables from stray magnetic interference, and the brisk, almost shorthand naming reflects its lab-and-engineering roots.
- composition
- Roughly 80% nickel with iron, copper, molybdenum
- name origin
- Named for mu, the symbol for magnetic permeability
- the trick
- Guides field lines through itself, shielding what's inside
- handle gently
- Bending or dropping ruins its shielding power
- real jobs
- Protects MRI machines, old CRTs, sensitive lab instruments
mumetal in transformer cores — common in audio equipment and power supplies since 1950s for reducing magnetic field leakage
mumetal in medical imaging — used in magnetoencephalography (meg) shielding rooms to measure brain magnetic fields without external interference