Ag Surface and Bulk Segregations in Sputtered ZrCuAlNi Metallic Glass Thin Films.

Michael K Steinhoff,Marcus Hans,Jochen M Schneider,Daniel Primetzhofer,Damian M Holzapfel,Deborah Neuß,Soheil Karimi Aghda,Clio Azina,Peter J Pöllmann

doi:10.3390/ma15051635

Michael K Steinhoff, Marcus Hans + Show 7 more

Open Access

https://doi.org/10.3390/ma15051635

Copy DOI

Journal: Materials	Publication Date: Feb 22, 2022
Citations: 3	License type: CC BY 4.0

Affiliation: RWTH Aachen University, Uppsala University

Abstract

We report on the formation of Ag-containing ZrCuAlNi thin film metallic glass (nano)composites by a hybrid direct-current magnetron sputtering and high-power pulsed magnetron sputtering process. The effects of Ag content, substrate temperature and substrate bias potential on the phase formation and morphology of the nanocomposites were investigated. While applying a substrate bias potential did not strongly affect the morphological evolution of the films, the Ag content dictated the size and distribution of Ag surface segregations. The films deposited at low temperatures were characterized by strong surface segregations, formed by coalescence and Ostwald ripening, while the volume of the films remained featureless. At higher deposition temperature, elongated Ag segregations were observed in the bulk and a continuous Ag layer was formed at the surface as a result of thermally enhanced surface diffusion. While microstructural observations have allowed identifying both surface and bulk segregations, an indirect method for detecting the presence of Ag segregations is proposed, by measuring the electrical resistivity of the films.

Highlights

Nanocomposites are being developed for a variety of applications as they allow combining the properties of two or more constituents
Bönninghoff et al discussed the growth of a Zr60 Cu25 Al10 Ni5 thin-film metallic glass (TFMG) produced by high-power pulsed magnetron sputtering (HPPMS) and direct current magnetron sputtering (DCMS), and have reported differences in the microstructure and density of the films produced [31]
Considering the material system of the pure MG being identical to that presented in this work, albeit from a target produced by a different manufacturer, films were reproduced in DCMS and HPPMS modes in order to confirm that the microstructures produced were featureless

Summary

Introduction

Nanocomposites are being developed for a variety of applications as they allow combining the properties of two or more constituents. Nanoscale reinforcements, such as nanoparticles (NPs), nanowires, etc., which possess unique physicochemical properties, can provide novel functionalities and/or enhance the properties of the matrix. Domingues and coworkers followed a similar approach to produce AlN:Ag nanocomposites from an Al target comprising a variable number of Ag pellets [10]. With this approach, the number of Ag pellets influenced the Ag content of the films, there is little flexibility over the deposition rate of the films as all metallic constituents are operated in the same conditions. Co-sputtering from independent targets, allows for better control over the deposition rates of each constituent, while varying Ag contents by adjusting the targets powers [11,12,13]

Methods

Results

Conclusion