화학공학소재연구정보센터
Thin Solid Films, Vol.447, 568-574, 2004
The evaporative deposition of aluminum coatings and shapes with grain size control
The direct deposition of coatings with a variable cross-section presents a challenge for the use of physical vapor deposition technology. Aluminum coatings with constant and variable cross-section profiles are useful for the evaluation of material behavior under extreme loading conditions, as for example under high strain rate. The synthesis of a variable cross-section with micron-scale design features in the as-deposited condition requires process innovation. It is now demonstrated that a 70-mum thickness gradient can be produced, from a 30 mum to a 100 mum plateau forming a wedge shape across a 800-mum path length, using a variable position shutter translated using a computer-controlled stepper motor. In addition, to deposit a desired grain size in the aluminum coatings first requires quantification of the established qualitative effects of time at temperature seen in growth models. An examination of the coating microstructure leads to a new quantitative result of a 0.41 eV(.)atom(-1) activation energy for ideal-grain growth behavior over the micron-to-millimeter scale at temperatures of 260-540 degreesC. (C) 2003 Elsevier B.V. All rights reserved.