This paper reports a mechanism for the formation of iron-arsenide films on metal substrates in the presence of molten lead (2-wt.% antimony and 0.3-wt.% arsenic). When iron samples were exposed to flowing molten lead at 500 degreesC for 100 h, an iron-arsenide film (approx. 40 mum) formed on the substrate. The film is composed of two layers: an outer-most layer approaching stoichiometric composition of iron-arsenide, and an inner layer a mixture of Fe-As-Sb-Pb. An abrupt change in elemental composition and texture is observed between the two layers. Film growth resulted in no obvious dimensional change in the substrate. Optimal film growth occurred at an oxygen potential of p(O2) similar to 10(-40) atm. (C) 2003 Elsevier B.V. All rights reserved.