Ball-milling with a fluid:: A powerful means for new syntheses

By reactive ball-milling in the presence of a fluid (either liquid as dodecane or gaseous as hydrogen), it is possible to synthesize nanomaterials as diverse as: alkali metal hydrides; well-crystallized highly anisometric graphite (HAG) whose typical particle size is a thickness of 40 nm for a mean diameter of several micrometers; a superdense lithium-graphite intercalation compound: LiC3; maghemite (gamma Fe2O3) and its composites with graphite. Most of those compounds present interesting electrochemical properties and can be used as anodes in lithium-ion batteries. Depending on the system, the role of the fluid can be either a shock moderator, avoiding the amorphization of the material (e.g. graphite), or a reagent (e.g. hydrogen forms alkali metal hydride, water oxidizes transition metal powders). Some reaction mechanisms are described in this paper with a particular attention to the oxidation by water of chromium, nickel and copper. (C) 2006 Elsevier B.V. All rights reserved.