ALTERNATIVE APPROACH TO NANOCOMPOSITE SYNTHESIS BY SPUTTERING

A new method is presented which circumvents the usual thermodynamic limitations (alloying and compound formation) in fabricating phase-separated materials. This opens whole new classes of materials that can be prepared as particulate composites.This method utilizes sputtering at high pressures (0.2-0.6 Torr) in a thermal gradient to produce nanoscale (<15 nm diameter) particles, which are then embedded in a matrix produced by normal sputtering. The microstructure and microhardness of 0.5-μm-thick composites of molybdenum particles (3-12 nm average particle size) in aluminum are presented as examples. This system cannot be prepared by the conventional phase separation technique of cosputtering.