Directional solidification of a eutectic is a novel route for the production of nanostructures. This method was applied to the quasibinary NiAl-Re system. Re as the minor phase forms fibers, which are parallel aligned in the NiAl matrix. At a temperature of 1690 +/-10 degrees C using a thermal gradient of 40 degrees C cm(-1) and a growth rate of 30 mm h(-1), the fibers formed had a diameter of about 400 run. An electrochemical method is presented here that simultaneously passivates the NiAl matrix and selectively electrodissolves the Re. In this manner, it was possible to form an array of nanopores each with the same diameter of 400 nm. The mechanisms behind this procedure, as well as the potential of this method for the production of nanoelectrode arrays or nanofilters are discussed. (c) 2005 Elsevier Ltd. All rights reserved.