ABSTRACT CTS-9730016 Robert Pachavis/MRS This proposal is being submitted for the support of Symposium FF: Surface Controlled Nanoscale Materials for High-Added-Value Applications at the Fall Materials Research Society Meeting During Dec. 1997 in Boston. Nanoscale materials have attached wide attention due to their superior properties. One of the main initial, now achieved, goals has been the development of scalable synthesis methods of nanosized powders, essentially for promising sintering and mechanical applications. However, as the size of the grains further decreases, the surface-to-bulk ratio dramatically increases, conferring to he first atomic layer a major role in the overall properties of the material. Indeed the chemical composition of the reactive particle surface becomes different from that of the bulk upon exposure to air contaminants. It has been realized recently that, not only clean synthesis processes are needed to obtain reproducible high purity nanosized powders, but also that tools and techniques to adequately characterize and monitor the very surface of the nanoparticles, in situ, independent of any bulk characterization are necessary. Moreover, the preservation or recovery of the desirable chemical properties of the surface of the grains need to be developed to facilitate and thus increase the industrial use of the nanosized powders in current technological processes. The major objective of this cross-disciplinary symposium is twofold. The fundamental aspect is to emphasize the relationship between the surface chemical composition of the nanoparticles, that of the grain boundaries, and the macroscopic physical properties of the consolidated material. The technological objectives is to evaluate new approaches of surface purity control and surface chemical modification to engineer superior nanostructured materials and composites. A complete tailoring of the surface properties is expected to lead to perfectly controlled consolidated materials and to have a g reat impact on the nanofabrication of electronic, optoelectronic and magnetic devices as well as biomedical-oriented compounds. ***
