Focused ion beam

About: Focused ion beam is a research topic. Over the lifetime, 12154 publications have been published within this topic receiving 179523 citations. The topic is also known as: FIB.

Bonding behavior studies of cold sprayed copper coating on the PVC polymer substrate

Abstract: Metallization of the polymer surface by cold spray technique is an attractive way of improving their electrical conductivity and erosive resistance properties. However, it is still challenging to achieve a dense and thick high-strength metal coating, such as copper, on the polymer surface by cold spray system, due to excessive surface erosion during the processing. In order to overcome these difficulties, in the present work, two different types of interlayers are proposed. The polyvinyl chloride (PVC) polymer substrate was initially coated with a spherical copper powder and a tin powder separately and then a thick copper coating was fabricated using a dendritic copper powder. The properties of the coatings, such as shear adhesion strength, Vickers hardness and electrical resistivity, were measured and the influence of the interlayer on the above properties and bonding behavior was studied using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and focused ion beam dissection (FIB) techniques. The results show that the deposition efficiency is highly sensitive to the glass transition temperature of the substrate, irrespective of the process gas pressure. The coating with spherical copper interlayer shows poor shear adhesion strength due to the dislodged polymer debris at the spherical/dendritic copper coating interface. The electrical conductivity of the coating is fairly low as compared to the bulk copper due to the pores and inter-particle defects.

Three Dimensional Chiral Metamaterial Nanospirals in the Visible Range by Vertically Compensated Focused Ion Beam Induced‐Deposition

Abstract: Fabrication and characterization of chiral metallic nanospirals for application as metamaterials in the visible and near infrared range are described. The structures consist of platinum helicoidal three-dimensional nanostructures realized by focused ion beam induced-deposition, where the interaction with incident light can be controlled as a function of light circular polarization state and spectral region, showing a circular dichroism across a wide range of optical wavelengths. An accurate size control and nanometer resolution on the fabrication of the chiral structures are achieved by exploring substrate surface charge effects on substrates with different electrical properties and by studying and implementing an accurate scanning procedure for the nanostructure growth that allows compensation of the proximity and charge effects. Optical measurements carried out on the nanospiral arrays using a high spatial resolution setup show a transmittance difference of the right- and left-circular polarized light near to 40%.

A FIB/TEM study of butterfly crack formation and white etching area (WEA) microstructural changes under rolling contact fatigue in 100Cr6 bearing steel

Abstract: Butterflies are microscopic damage features forming at subsurface material imperfections induced during rolling contact fatigue (RCF) in rolling element bearings. Butterflies can lead to degradation of the load bearing capacity of the material by their associated cracks causing premature spalling failures. Recently, butterfly formation has been cited to be related to a premature failure mode in wind turbine gearbox bearings; white structure flaking (WSF). Butterflies consist of cracks with surrounding microstructural change called ‘white etching area’ (WEA) forming wings that revolve around their initiators. The formation mechanisms of butterflies in bearing steels have been studied over the last 50 years, but are still not fully understood. This paper presents a detailed microstructural analysis of a butterfly that has initiated from a void in standard 100Cr6 bearing steel under rolling contact fatigue on a laboratory two-roller test rig under transient operating conditions. Analysis was conducted using focused ion beam (FIB) tomography, 3D reconstruction and transmission electron microscopy (STEM/ TEM) methods. FIB tomography revealed an extensive presence of voids/cavities immediately adjacent to the main crack on the non-WEA side and at the crack tip. This provides evidence for a void/cavity coalescence mechanism for the butterfly cracks formation. Spherical M3C carbide deformation and dissolution as part of the microstructural change in WEA were observed in both FIB and STEM/TEM analyses, where TEM analyses also revealed the formation of superfine nano-grains (3–15 nm diameter) intersecting a dissolving spherical M3C carbide. This is evidence of the early formation of nano-grains associated with the WEA formation mechanism.

Surface plasmon polariton modes in a single-crystal Au nanoresonator fabricated using focused-ion-beam milling

Abstract: We use focused-ion-beam milling of a single-crystal Au surface to fabricate a 590-nm-long linear ridge that acts as a surface plasmon nanoresonator. Cathodoluminescence imaging spectroscopy is then used to excite and image surface plasmons on the ridge. Principal component analysis reveals distinct plasmonic modes, which proves confinement of surface plasmon oscillations to the ridge. Boundary-element-method calculations confirm that a linear ridge is able to support highly localized surface plasmon modes (mode diameter <100 nm). The results demonstrate that focused-ion-beam milling can be used in rapid prototyping of nanoscale single-crystal plasmonic components.