Simultaneous Decomposition and Dewetting of Nanoscale Alloys: A Comparison of Experiment and Theory

Document Type

Article

Publication Date

3-2-2021

Abstract

We consider the coupled process of phase separation and dewetting of metal alloys of nanoscale thickness deposited on solid substrates. The experiments involve applying nanosecond laser pulses that melt the Ag40Ni60 alloy films in two setups: either on thin supporting membranes or on bulk substrates. These two setups allow for extracting both temporal and spatial scales on which the considered processes occur. The theoretical model involves a longwave version of the Cahn-Hilliard formulation used to describe spinodal decomposition, coupled with an asymptotically consistent longwave-based description of dewetting that occurs due to destabilizing interactions between the alloy and the substrate, modeled using the disjoining pressure approach. Careful modeling, combined with linear stability analysis and fully nonlinear simulations, leads to results consistent with the experiments. In particular, we find that the two instability mechanisms occur concurrently, with the phase separation occurring faster and on shorter temporal scales. The modeling results show a strong influence of the temperature dependence of relevant material properties, implying that such a dependence is crucial for the understanding of the experimental findings. The agreement between theory and experiment suggests the utility of the proposed theoretical approach in helping to develop further experiments directed toward formation of metallic alloy nanoparticles of desired properties.

Identifier

85101402715 (Scopus)

Publication Title

Langmuir

External Full Text Location

https://doi.org/10.1021/acs.langmuir.0c02964

e-ISSN

15205827

ISSN

07437463

PubMed ID

33587633

First Page

2575

Last Page

2585

Issue

8

Volume

37

Grant

CBET-1603780

Fund Ref

National Science Foundation

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