کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1666462 | 1518078 | 2012 | 7 صفحه PDF | دانلود رایگان |
This paper describes an experimental technique to identify robust nanoscale coatings for improving the long-term reliability of metallic microelectromechanical systems. More specifically, the influence of nanoscale alumina coatings on the fatigue crack initiation process in 20 μm thick electrodeposited Ni films was investigated in a mild (30 °C, 50% RH) and harsh (80 °C, 90% RH) environment. Atomic-layer-deposited alumina layers, with thicknesses of 5 and 25 nm, were coated on Ni fatigue micro-resonators, and the fatigue degradation behavior in the very high cycle fatigue regime was compared to that of uncoated structures. Evidence based on post-test scanning electron microscopy and resonant frequency evolution plots shows that the coatings do not prevent the formation of fatigue extrusions and micro-cracks. However, their formation is likely delayed for the 25 nm thick alumina-coated Ni films.
► Effect of alumina coatings (5 and 25 nm thick) on fatigue initiation in nickel films
► Fatigue tests were performed at 30 °C, 50% relative humidity (RH) and 80 °C, 90% RH.
► Coatings did not prevent fatigue extrusions and micro-cracks.
► 25 nm coatings likely delayed the formation of fatigue extrusions and micro-cracks.
► The technique can be used to identify reliable nanoscale coatings.
Journal: Thin Solid Films - Volume 526, 30 December 2012, Pages 176–182