A method has been developed that produces an AlN coating on an aluminum substrate at 540 °C. It builds on the techniques previously reported (D. Kent, G. B. Schaffer, T. B. Sercombe, J. Drennan, Scripta Mater. 2006, 54, 2125), but uses aluminum powder which reduced the reaction time and required less stringent atmosphere control. Initially, the nitride formed as a shell round the particles and was accompanied by the filling of the interstitial pores by a secondary aluminum. At longer times, both the powder and the secondary aluminum nitrided, resulting in a relatively dense coating.