The influence of the boron content on the various properties of nanocrystalline Ni-B alloy produced by electrodeposition was investigated. The considerable reduction in grain size was observed with increasing boron content. The internal stress was tensile and increased linearly with increasing boron content. Hardness increased up to 750 Hv at 2 at.% boron and then kept the value to 11 at.% boron for as-plated Ni-B coatings. The hardness of Ni-B films increased considerably due to the intermetallic Ni3B precipitation by the heat treatment and maximum hardness of each coating increases with boron content. Wear resistance decreased with increasing the boron content because of high friction coefficient and brittle fracture of coating with high content of boron. (C) 2005 Elsevier Ltd. All rights reserved.