Synthesis of nanocrystalline materials by electron beam evaporation

摘要

A new nanophase materials preparation system using electron beam heating to vaporize materials in inert or reactive gaseous environments has been developed. With this system a wide variety of materials can be produced in nanophase form with minimum contamination. Besides enabling the production of pure metals, including refractory materials, the system is designed to produce alloys and multicomponent materials by simultaneous evaporation of two or more elements. The electron beam position and dwell time are set by computer, allowing great control of the evaporation conditions. Results obtained to-date indicate great promise for obtaining increased yields and smaller grain sizes than typically obtainable when nanophase materials are produced using resistive heating. A description of nanophase (gamma)-Al(sub 2)O(sub 3) produced with a mean grain size of approximately 2.5 nm is given as a demonstration of the capabilities of the system.