Nov. 14, 2011

Ni-Nanostructures Within Porous Silicon

A semiconducting/ferromagnetic nanocomposite, consisting of a porosified silicon wafer and deposited Ni-nanostructures, is presented. Porous silicon matrices achieved by anodization of a highly n doped wafer offer oriented pores with an average pore-diameter of 80 nm. Within these pores Ni-nanostructures are deposited resulting in a ferromagnetic system with specific magnetic properties. SEM and TEM investigations are performed to get a correlation between morphology and magnetic behavior.

Introduction
moreOct. 26, 2011

Preparation of TEM Samples

A special method of Transmission Electron Microscopy (TEM) samples preparation is described in this article. Rapidly solidified alloy have very fine structure formed by matrix and intermetallic phases. Common TEM sample of bulk material allows observe the distribution of intermetallic particles but not their detail characteristic because of their small size. To describe the intermetallic phases is necessary to extract them from matrix. It is possible to do that by selective matrix dissolution in the solution of tartaric acid and iodine in methanol. moreOct. 11, 2011

Filtration Membranes, Water and the ESEM

Great progress in the filtration performance of microfiltration membranes has been achieved in the past few years. As a consequence the structures of the respective membranes have become more and more intricate. New microscopic characterization methods are therefore necessary to reveal the membrane structure in full detail. The environmental scanning electron microscope (ESEM) has the potential for also studying microfiltration membranes in their wet state. The dynamics of the wetting and drying of the membrane surface can be imaged at sub-µm resolution. moreOct. 03, 2011

Electron Diffraction on Barium Titanate Crystals

Apart from the domain structures that were discovered on BaTiO3 single crystals by means of TEM, there are a couple of unusual effects we know very little about. Some of these effects that require further research are transition structures, or optical radiation which accompanies the diffraction of electrons close to the temperature of phase transition as well as far below. Impact of neutrons or other heavy particles forms many spots on the surface of the negative (fig. 1.)

Introduction
moreSep. 19, 2011

VM12 Strengthing by Precipitates - TEM Study of Precipitates in the Martensitic VM12 Steel

Martensitic VM12 steel was recently developed for advanced coal-fired power stations. Its creep resistance is dependent on a stability of microstructure. Destabilization of microstructure is caused by recovery and softening processes of a tempered martensite and depends on changes of a dislocation substructure and morphology of secondary particles during creep. Quantitative TEM analyses of VM12 steel were ­undertaken to determine the microstructure parameters after creep at 625°C up to 30.000h.

Experimental
moreSep. 05, 2011

Phase Growth in Wire Bond Interconnects - Microstructural Characterization by EBSD

Gold wire bonding on aluminium pads plays an important role in microelectronic packaging. The reliability and lifetime of the interconnection is determined by intermetallic phases formed at the Au/Al interface. Five phases are stable at room temperature. Some of them are supposed to undergo degradation pro­cesses due to mechanical stress or chemical reactions during IC lifetime. For microstructural characterization, investigations by EBSD are applied as an alternative to expensive TEM analyses.

Introduction
moreAug. 11, 2011

Communication Problems in Nerve Cells

Is the cause of diseases such as Alzheimer‘s, epilepsy and schizophrenia rooted in a deficiency or rise in chemical messengers? The „Functional Cell Biology" working group at the Charité University Hospital‘s Institute for Integrative Neuroanatomy in Berlin is looking into this and similar issues. The results are forming the basis of a fundamental understanding of the diseases and are intended to provide indications for therapeutic approaches. Researchers are employing the latest imaging and image analysis techniques and methods in the course of their investigations.
moreAug. 08, 2011

3D Elemental Mapping in the ESEM - A Combination of Serial Block-face SEM and EDS

The combination of serial block-face scanning electron microscopy and energy dispersive x-ray spectroscopy (EDS) is demonstrated for 3D elemental analysis of materials, enabling investigations of large sample volumes compared to other tomographic techniques. The approach involves cutting a stack of 200 slices from an aluminum-copper alloy specimen and generating EDS maps after each cut. more