In this paper the problem of metallographic image processing is considered. It is developed a new approach to filtering a multiplicative noise (stria) on metallographic images. This approach is based ...on the spectral analysis of images and finding the spectral regions that carry information about stria. Also it is proposed a new approach to eliminate the deformation lines of the material on the metallographic images. This approach consists of deformation line localization algorithm and smoothing filtering procedure of localized regions.
In fuel cells, stacks of several hundred bipolar plates are combined in membrane electrode assemblies, in which the electrochemical reactions take place. As a result, it must be possible to produce ...the bipolar plates cost-efficiently. In addition, the corrosion resistance in the surrounding medium and the electrical conductivity have to be sufficiently high. As stainless steels show passivation over time, more expensive materials, like graphite or noble-metal coatings, are used. This paper describes an alternative coating, which can fulfil the above-mentioned requirements. Using electroplating, Cr coatings with thicknesses > 20 µm can be deposited at low costs and REACH compliant. Subsequently, the Cr layers are gas nitrided resulting in a dense Cr-N coating with electrical and corrosion properties exceeding the ones of common stainless steels. Using this new approach, well-performing fuel cells could be produced cost-efficiently.
Coordination complexes M(O2CCH2OC2H4OMe)2 (M = Co, 4; M = Mn, 5) are accessible by the anion exchange reaction between the corresponding metal acetates M(OAc)2(H2O)4 (M = Co, 1; M = Mn, 2) and the ...carboxylic acid HO2CCH2OC2H4OMe (3). IR spectroscopy confirms the chelating or μ-bridging binding mode of the carboxylato ligands to M(II). The molecular structure of 5 in the solid state confirms a distorted octahedral arrangement at Mn(II), setup by the two carboxylato ligands including their α-ether oxygen atoms, resulting in an overall two-dimensional coordination network. The thermal decomposition behavior of 4 and 5 was studied by TG-MS, revealing that decarboxylation occurs initially giving M(CH2OC2H4OMe)2, which further decomposes by M–C, C–O and C–C bond cleavages. Complexes 4 and 5 were used as CCVD (combustion chemical vapour deposition) precursors for the deposition of Co3O4, crystalline Mn3O4 and amorphous Mn2O3 thin films on silicon and glass substrates. The deposition experiments were carried out using three different precursor solutions (0.4, 0.6 and 0.8 M) at 400 °C. Depending on the precursor concentration, particulated layers were obtained as evidenced by SEM. The layer thicknesses range from 32 to 170 nm. The rms roughness of the respective films was determined by AFM, displaying that the higher the precursor concentration, the rougher the Co3O4 surface is (17.4–43.8 nm), while the manganese oxide films are almost similar (6.2–9.8 nm).
To produce silver-based contact materials such as silver/tin oxide different ways are possible. All usual technologies have their typical advantages and disadvantages. Expensive techniques are ...characterised by a very fine reinforcement distribution. Techniques with a high output quantity display a very limited particle distribution within the matrix material.
By means of the economical mechanical alloying process, particle-reinforced metal-matrix composite powders with a fine distribution of the reinforcement within the matrix material can be produced. This contribution shows the morphology and microstructure of mechanically alloyed silver-based powders by means of the high-energy ball-milling process as well as the microstructure and mechanical properties of the consolidated materials. The objective of the present investigation has been the successful and reproducible production of particle-reinforced metal-matrix composites as well as the reduction of the noble-metal part by increasing the content of the reinforcement. Current investigations present a successful increase of the oxide content to 17 wt.-%.
Electroplated composites with incorporated nanoparticles become a key material in the fabrication of microsystem devices. A good survey of composites with nickel matrix is given in 1. ...Electrodeposition of alumina particles (13 nm diameter, content around 1 Wt %) in nickel from an acidic electrolyte has been investigated using a nickel sulfamate bath with a particle loading of 10 g/l. Direct current (DC) deposition was compared to pulse-reverse plating (PRP) which can facilitate higher amounts. Details are given in 2. Materials properties depend on the particle distribution, their bonding to the matrix and their influence on the microstructure of the matrix which has been characterized by TEM, STEM, SEM and EBSD.
The electrodeposition of gold is a key technology in the fabrication of many microsystem devices comprising gold composites with improved electronic and mechanical properties 1. Multiwalled carbon ...nanotubes (CNT) of 20–40 nm in diameter were obtained by catalytic decomposition of acetylene on an iron catalyst. Ultradispersed diamond (UDD) was obtained by detonation synthesis (Caspio SA, Switzerland). Gold composites were electroplated using a sulphite gold electroplating bath with a CNT loading of 3 g/l and a UDD loading of 20 g/l, respectively 2.
A comparative study of 150 carotid angiographies carried out under local anaesthesia and the same number under halothane anaesthesia did not show any great deviation from the well-known filling rates ...of the counter-lateral carotid region and the ipsilateral A. cerebri posterior nor any striking differences in the two methods of anaesthesia which could convince of a favourable influence of halothane on the demonstration of the vessels. The causative factors of the filling of adjacent vascularisation regions can certainly only be explained from the complex co-action of physiological and any external factors in cerebral angiography.
