The kinetics and mechanisms of interface reactions in a unidirectional continuous SiC fiber-reinforced Ti-17 matrix composite were investigated using transmission electron microscopy and scanning electron microscopy. It was found that a reaction zone (RZ) consisting of two-layered TiC-type carbide forms at the fiber/matrix interface during fabrication of the composite. After isothermal exposure at elevated temperatures, the two-layered TiC-type carbide is inherited, and a new TiC-type carbide layer forms within the RZ after exposure at temperatures lower than 900°C, while a new Ti3C2-type carbide layer forms after exposure at 900°C. It was also observed that the growth of RZ is a diffusion-controlled and temperature-dependent process, obeying the Fick's law-based parabolic relationship and the Arrhenius equation. Two material constants, the temperature-independent rate constant k0 and activation energy Q, are determined as 31.5 × 10−4µm/s1/2 and 49.9 kJ/mol, respectively.

Here, we describe a method of acquisition of fast fluorescent signals with the help of the laser scanning confocal microscope (LSCM). Our method permits an increase in the temporal resolution of acquired signals. The method is based on LSCM recordings of fast fluorescent signals with the shortest achievable time sweep, which are performed with the help of a proprietary algorithm. A series of recordings is made in multiple steps; at each step, the fluorescent signal is incremented by a time interval smaller than the time sweep of the frame of LSCM. The size of the increment determines the achievable time resolution. The convolution of the recorded images results in a signal with the temporal resolution determined by the chosen time increment. This method was applied to register the change in fluorescence (calcium transient) of calcium dye preloaded into peripheral nerve endings by electrical stimulation of the motor nerve. Calculated parameters of the calcium transient were identical to the parameters obtained earlier with the help of a high-speed camera and photodiode. We conclude that the method described here can be applied for the registration of fast fluorescent signals by LSCM with a high spatial and temporal resolution.

High-temperature scanning electron microscopy allows the direct study of the temperature behavior of materials. Using a newly developed heating stage, tilted images series were recorded at high temperature and 3D images of the sample surface were reconstructed. By combining 3D images recorded at different temperatures, the variations of material roughness can be accurately described and associated with local changes in the topography of the sample surface.

A thin-walled copper (Cu)–tin (Sn) alloy cylinder was treated after spinning at 200–400°C for 0.5 h. The characteristics of the alloy microstructure under different temperatures were analyzed through electron back-scattered diffraction. The results were as follows. The grain size at 200–300°C decreases as the heat treatment temperature rises, but the grain size at 400°C increases. At 200–300°C, the microstructure primarily consists of deformed grains. It is found that the main reason for the formation of high-angle grain boundaries (HAGBs) is static recrystallization. For the grain boundary orientation differential, the low-angle sub-grain boundary gradually grows into the HAGB, and multiple annealing twin Σ9 boundaries appear. Grain orientation is generally random at any temperature range. The mechanical property test indicated that, at the upper critical recrystallization temperature of 300°C, the elongation of the Cu–Sn alloy gradually increases, and its yield strength and ultimate tensile strength rapidly decrease.

In microstructural corrosion studies, knowledge on the initiation of corrosion on an nm-scale is lacking. In situ transmission electron microscope (TEM) studies can elucidate where/how the corrosion starts, provided that the proper corrosive conditions are present during the investigation. In wet corrosion studies with liquid cell nanoreactors (NRs), the liquid along the electron beam direction leads to strong scattering and therefore image blurring. Thus, a quick liquid removal or thickness control of the liquid layer is preferred. This can be done by the use of a Peltier element embedded in an NR. As a prelude to such in situ work, we demonstrate the local wetting of a TEM sample, by creating a temperature decrease of 10 ± 2°C on the membrane of an NR with planar Sb/BiSb thermoelectric materials for the Peltier element. TEM samples were prepared and loaded in an NR using a dual-beam focused ion beam scanning electron microscope. A mixture of water vapor and carrier gas was passed through a chamber, which holds the micro-electromechanical system Peltier device and resulted in quick formation of a water layer/droplets on the sample. The TEM analysis after repeated corrosion of the same sample (ex situ studies) shows the onset and progression of O2 and H2S corrosion of the AA2024-T3 alloy and cold-rolled HCT980X steel lamellae.

With the growing importance of three-dimensional and very large field of view imaging, acquisition time becomes a serious bottleneck. Additionally, dose reduction is of importance when imaging material like biological tissue that is sensitive to electron radiation. Random sparse scanning can be used in the combination with image reconstruction techniques to reduce the acquisition time or electron dose in scanning electron microscopy. In this study, we demonstrate a workflow that includes data acquisition on a scanning electron microscope, followed by a sparse image reconstruction based on compressive sensing or alternatively using neural networks. Neuron structures are automatically segmented from the reconstructed images using deep learning techniques. We show that the average dwell time per pixel can be reduced by a factor of 2–3, thereby providing a real-life confirmation of previous results on simulated data in one of the key segmentation applications in connectomics and thus demonstrating the feasibility and benefit of random sparse scanning techniques for a specific real-world scenario.

Atom probe tomography (APT) has emerged as an important tool in characterizing three-dimensional semiconductor devices. However, the complex structure and hybrid nature of a semiconductor device can pose serious challenges to the accurate measurement of dopants. In particular, local magnification and trajectory aberration observed when analyzing hybrid materials with different evaporation fields can cause severe distortions in reconstructed geometry and uncertainty in local chemistry measurement. To address these challenges, this study systematically investigates the effect of APT sampling directions on the measurement of n-type dopants P and As in an Si fin field-effect transistor (FinFET). We demonstrate that the APT samples made with their Z-axis perpendicular to the center axis of the fin are effective to minimize the negative effects that result from evaporation field differences between the Si fin and SiO2 on reconstruction and achieve improved measurement of dopant distributions. In addition, new insights have been gained regarding the distribution of ion-implanted P and As in the Si FinFET.

Understanding how catalysts work during chemical reactions is crucial when developing efficient catalytic materials. The dynamic processes involved are extremely sensitive to changes in pressure, gas environment and temperature. Hence, there is a need for spatially resolved operando techniques to investigate catalysts under working conditions and over time. The use of dedicated operando techniques with added detection of catalytic conversion presents a unique opportunity to study the mechanisms underlying the catalytic reactions systematically. Herein, we report on the detailed setup and technical capabilities of a modular, homebuilt gas feed system directly coupled to a quadrupole mass spectrometer, which allows for operando transmission electron microscopy (TEM) studies of heterogeneous catalysts. The setup is compatible with conventional, commercially available gas cell TEM holders, making it widely accessible and reproducible by the community. In addition, the operando functionality of the setup was tested using CO oxidation over Pt nanoparticles.