Rapid multi-property assessment of compositionally modulated Fe-Co-Ni thin film material libraries

Next-generation high frequency, high power density, and high operating temperature electrical machines require superior materials which possess an attractive combination of structural as well as functional properties. Development of such new materials by conventional methods is very slow, expensive, and restricted to a few compositions. Hence, we addressed this challenge by the accelerated assessment of multiple properties of a range of Fe-Co-Ni based material compositions. We utilized the magnetron co-sputtering method to prepare compositionally modulated ternary Fe-Co-Ni thin film alloy (TFA) libraries. The structural, electrical, magnetic, and mechanical properties of these libraries were assessed. The structure and properties were found to vary over a wide range with composition and thin film processing parameters. The Fe-Co-Ni TFA library prepared at a substrate temperature of 500 °C exhibited a good combination of multiple properties. The specific alloy composition Ni54.9Co33.1Fe12 was found to possess an attractive blend of properties. Thus, a rapid property assessment of TFA libraries of a wide range of compositions and processing conditions was successfully used to identify a novel specific composition and processing protocol which exhibited an attractive mix of properties.