We present a new method for nitriding iron at low temperatures. First, iron is coated with a thin layer of nickel(∼36 nm), after which it is exposed to anNH3 atmosphere at temperatures below 300 °C. Underneath the nickel layer&egr;-Fe3−xNis formed at temperatures as low as 225 °C, while uncovered iron samples show a large uptake of oxygen after the same treatment. The nickel layer prevents the oxidation of iron by impurities in theNH3 gas, and acts as a catalyst for the decomposition ofNH3.After decomposition the atomic nitrogen diffuses through the nickel layer towards the iron. With the process described, pore-free iron nitrides can be formed at low temperatures. ©1997 American Institute of Physics.