Sirion 400 nc

The final dried new AuNPs were examined using a scanning electron microscope (SEM), Sirion 400 NC (FEI Sirion 400 NC, FEI Technologies Inc., Hillsboro, OR, USA), with an EDS INCA 350 (Oxford Instruments, Oxford, UK). The samples were prepared by applying the dried AuNPs onto an SEM stub holder with graphite tape.

A scanning electron microscope (SEM), Sirion 400 NC (FEI Sirion 400 NC, FEI Technologies Inc., Hillsboro, OR, USA), with an EDS INCA 350 (Oxford Instruments, UK), was used for the investigations of the fracture surface for the prepared PLA/Ni/Y₂O₃ composite and pure PLA. The samples for SEM examination were prepared by breaking directly in liquid N₂, thus preserving the authenticity of the surface for microscopic observation. The investigated surfaces of the samples were sputter coated with Au for 60 s, in order to produce a conductive film and improve the SEM imaging of the samples.

A Scanning Electron Microscope (SEM) Sirion 400NC (FEI, Hillsboro, OR, USA) with an Energy-Dispersive X-ray (EDX) spectroscope INCA 350 (Oxford Instruments, Abingdon, Oxfordshire, UK) was used for the microstructure observation and micro-chemical analyses of the brass tiles. Two methods of investigation were carried out: the first, direct SEM/EDX observation without surface preparation of the dark brass tile; and secondly on the polished surface, which was treated manually with diamond paste 1 µm and felt so that oxide products and other contamination were removed. The requirement was to estimate the chemical composition inside (by volume) the brass tile.

The AuNP and PMMA/AuNP samples were examined with SEM microscopes Quanta 200 3D (FEI, Hillsboro, OR, USA) and Sirion 400NC (FEI, Hillsboro, OR, USA) with an Energy-Dispersive X-ray spectroscope INCA 350 (Oxford Instruments, Abingdon, UK). The samples were put on SEM holders with conductive carbon adhesive tape for the examinations.

A scanning electron microscope, Sirion 400NC (FEI, FEI, Hillsboro, OR, USA), with an energy-dispersive X-ray spectroscope, INCA 350 (Oxford Instruments, Oxford, UK), was used for the SEM/EDS analysis. It had a Schottky electron source, where the field emission produces a jet of electrons with a small diameter and a high density. The result is high resolution, even at low voltages: 1.0 nm at 15 kV and 2.0 nm at 1 kV. The AuNPs’ suspensions were put dropwise onto the SEM holders (mesh) with conductive carbon adhesive tape, which allowed better SEM observation. The SEM holders were left to dry in a desiccator for 1 day before the SEM investigations were carried out.

During the 18 months of exposure in the seawater environment, pitting was located on the Ni–Ti sample, as shown in Figure 2.
The chemical composition of the selected Ni–Ti alloy surfaces was determined through the use of a high-resolution field emission SEM (Sirion 400 NC; FEI, Hillsboro, OR, USA), equipped with an INCA 350 EDX detector (Oxford Instruments, Abingdon, Oxfordshire, UK). The EDX semi-quantitative analysis determined the chemical composition of the Ni–Ti alloy surface after corrosion, as well as the content of the elements on the surface edge and hole of the pitting. Sixty spectra were considered in total. Five analysis locations were in the hole of the pitting and five were on top of the edge. The chemical composition of the metal surfaces was scanned for each analysis location—up to six spectra per location under the magnification of 200 μm and 300 μm.

The membrane morphology (structure, homogeneity/distribution) before and after filtration of bacterial suspensions was determined using scanning electron microscopy (SEM) imaging and optical microscopy. The SEM imaging of the samples’ surfaces and cross sections was performed using a FEI Sirion 400NC (FEI, Hillsboro, Oregon, USA) microscope at different magnifications. The membranes tested in the filtration experiments were immersed in 30 mL of 70% ethanol twice consecutively for half an hour in order inactivate viable bacterial cells and to fix them. Then, they were transferred to sterile Petri dishes and left to dry for 3 days at 37 ± 0.5 °C before further preparation for SEM analysis.
For light microscopy, selected non-tested membranes were cut into smaller square pieces (approx. 5 mm × 5 mm) and immersed in deionised water for 15 min at room temperature. Afterwards, the membrane pieces were dissected into individual slivers, which were transferred onto an objective glass, and observed under an Olympus SZ61TR stereomicroscope equipped with an Olympus DP73 camera (Olympus, Tokyo, Japan).