Massive Ag migration through metal/ceramic nano-multilayers: an interplay between temperature, stress-relaxation and oxygen-enhanced mass transport
Mirco Chiodi , Claudia Cancellieri , Frank Moszner , Mariusz Andrzejczuk , Jolanta Janczak-Rusch , Lars P. H. Jeurgens
AbstractThe phase stability and microstructural evolution of nano-multilayer (NML) coatings during thermal treatments have attracted increasing attention in several technological fields, such as plasmonics, optics and joining. In the present study, the microstructural evolution of (Ag/AlN)5nm/10nm NML coating upon heating in air and under vacuum was investigated by a combinatorial approach using SEM, TEM, XPS and XRD (both in the laboratory and at the synchrotron facility). Fast heating of the Ag/AlN NML in air up to 420 1C leads to an extensive migration of nano-confined Ag to the NML surface at temperatures as low as 200 1C, much below the Ag bulk melting point. Remarkably, the migration of Ag towards the surface is negligible for a similar heat treatment under vacuum, as well as for a thick Ag layer (i.e. in the absence of a nano-confinement of Ag). Outward migration of Ag is driven by the reduction of internal interfaces (i.e. nanograin- and phase boundaries) in combination with the relaxation of thermally induced compressive stresses. The enhanced mobility of Ag in an O-rich atmosphere is attributed to the reduction of the activation energies for vacancy formation in the confined Ag nanolayers, as induced by the chemical interaction of inwardly diffusing O with Ag along Ag/AlN interfaces. The combined effects of nano-confinement, thermal stresses and an O-rich atmosphere in the Ag/AlN NML may be exploited for novel low-temperature joining applications.
|Journal series||Journal of Materials Chemistry C, ISSN 2050-7526, e-ISSN 2050-7534|
|Publication size in sheets||0.55|
|Score|| = 40.0, 10-06-2020, ArticleFromJournal|
= 40.0, 10-06-2020, ArticleFromJournal
|Publication indicators||= 16; = 8; : 2016 = 1.265; : 2016 = 5.256 (2) - 2016=5.312 (5)|
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