nanometer per year
Corrosion rateexact by definition
The nanometre per year is 10⁻⁹ metres of penetration a year, one thousandth of a micrometre per year and about 1/25400 of a mil per year. It is the unit for materials that barely corrode at all: passive stainless steel and titanium in benign water, archaeological metals, and the container corrosion allowances assumed in long-term nuclear waste isolation. The factor is exact, being an SI prefix.
Watch out: A rate this low is almost never a measured penetration. It is usually inferred from an electrochemical current density or extrapolated from a short exposure, and uniform penetration is the wrong model for passive alloys anyway: they fail by pitting, crevice attack or stress corrosion cracking at rates that a uniform average hides completely.
| 1 | 0.000001 |
One nanometer per year in every corrosion rate unit
| 1 | nanometer per year (nm/yr)this unit | |
| 0.001 | micrometer per year (μm/yr) | |
| 0.0000393701 | mil per year (mpy) | |
| 0.000001 | millimeter per year (mm/yr) | |
| 3.93701e-08 | inch per year (in/yr) | |
| 1.00000e-09 | meter per year (m/yr) |