Abscheidung und Werkstoffaufbau galvanischer Dispersionsschichten

Deposition and structure of electroplated composite layers The electrodeposition of nickel layers with incorporated ceramic nanoparticles, TiO₂ and Al₂O₃ was carried out with the aid of ultrasound during electroplating. The ultrasound guarantees a permanent desagglomeration of nanoparticles in the electrolyte. Therefore, nanoparticles were incorporated homogeneously and fine‐dispersedly. The incorporation of nanoscaled particles, the changes of the layer structure and the crystallites were investigated in comparison to conventionally electrodeposited nickel layers by means of SEM, EDX, EBSD and XRD.     

Abscheidung von Palladium und Palladiumlegierungen mit hohen Schichtdicken für die Mikrosystemtechnik

Deposition of Thick Palladium and Palladium Alloy Layers for Microsystems Technology Layers of metals and alloys deposited in microstructures usually require to be thicker than the 100 μm which is the approximate height of the structure. The deposited form of noble metals used in microsystems must be non‐stressed, ductile and free of cracks and pores. As the thickness of layers deposited from commercial noble metal electrolytes will rarely exceed 10 μm without loss of quality, developing an electrolyte system suitable for microsystems involves finding appropriate additives and deposition parameters. Details are given of deposit characterisation, the parameters of the deposition technology and some practical examples. Initial results are presented and discussed.     

Theoretische und praktische Betrachtungen zur Abscheidung verschiedener Schichttypen am Beispiel von galvanisch Nickel

Theoretical and practical views on the deposition of different layer types exampled at electroplated nickel Electroplated metals exhibit different growth types as a function of metal salt concentration, current density, pH‐value, kind and quantity of organic additives, bath temperature, outer convection, substrate characteristics and character of the plated metal. As a function of the type of layer changes in the layer characteristics are expected by parameter variation. Refinement of understanding in structure characteristic relations at Watts nickel layers was done concerning the effect of substantial deposition parameters, like current density, electrolyte concentration and organic additives. These parameter effect the type of layer, texture, hardness and corrosion behavior. Simply combination of several additives could achieve finer crystallites with transitions from the FT type to UD forms and thus hardness increases over up to 200 % compared with pure electrolytes. The applied organic additives lead however frequently to a degradation of the corrosion behavior. With Watts nickel no significant change of the type of layer was registered by variation of the current density. With higher current density an increase of hardness and corrosion resistance was determined.     

Abscheidung,Charakterisierung und Anwendung von Plasma‐Polymerschichten auf HMDSO‐Basis

Deposition, Characterisation and Application of HMDSO‐based Plasma Polymer Films High quality organosilicone coatings can be produced via plasma enhanced chemical vapor deposition of hexamethyldisiloxane (HMDSO). In this article aspects of deposition, analysis and application of HMDSO/O₂ processes are presented. The coatings’ organic/inorganic character can be adjusted by an appropriate combination of plasma power and gas mixture which is shown by XPS. Particularly multi layer and gradient layer systems can be deposited within the same process. Quantitative chemical depth profiling of such layer systems can be performed by secondary neutral mass spectrometry (SNMS). AFM investigations exhibit that the surface roughness of the coatings is determined by the appearance of hemispherical agglomerates, which is more pronounced, the more glass‐like the coatings are. As an example of use it is shown, that an appropriate HMDSO plasma treatment can distinctly improve the tribological behavior of elastomer devices. The presented work is done within a project of the German Federal Ministry of Education and Research (BMBF) entitled: “nano functionalization of interfaces for data‐, textile‐, building‐, medicine‐, bio‐, and aerospace‐ technology”.     

Zur adsorptiven Abscheidung von Isocyanaten aus Abgasen

Ohne Zusammenfassung Reihe 3 Nr. 100 (1985) der FORTSCHRITT-BERICHTE VDI gibt den vollen Wortalut der Arbeit als Manuskript gedruckt wieder. 84 Seiten, Preis 58 DM. Bestellungen an die VDI-Verlag GmbH, Postfach 1139, 4000 Düsseldrof 1.     

Abscheidung von SiOxNy Sperrschichten durch Dual Magnetron Sputtering

Silicon Oxynitride Barrier Layers Deposited by Pulsed‐DC Dual Magnetron Sputtering SiO_xN_y barrier layers have been deposited using pulsed direct current (DC) and medium frequency (MF) sputtering on large area (GEN 5) glass substrates. Several process parameters, such as discharge voltage, boost voltage, and discharge frequency were varied with the goal of increasing system productivity and reducing the arc rate during SiO_xN_y deposition. The arc rate during operation with pulsed DC dual magnetron sputtering was lower than for MF sputtering; however for the same nominal discharge power, the deposition rate using pulsed DC power supplies was slightly lower than for operation with MF. The suitability for use as a barrier layer was deduced by capping the SiO_xN_y layers with DC sputtered ZnO:Al coatings and subjecting the sample stacks to anodic and cathodic degradation and subsequent storage in a damp atmosphere.     

Maßänderungen von Zinkdruckgußlegierungen infolge von Alterung

Changes in dimension of zinc die-casting alloys due to aging . It is known since a long time that die-cast elements are subject to slight changes in dimension even when they are made of high-grade zinc alloys standardized for that purpose. But in prior research it was apparently still unknown that the amount of these changes is influenced, among other things, by the cooling conditions of the pieces following the casting process. It is therefore impossible to compare off-hand the values coming from different sources. The changes in dimension were reinvestigated for that reason with regard to the cooling conditions, and the results were some new findings in this field.     

Kontrollierte Massenänderungen von Tropfen in einem akustischen Stehwellen-Positionierer

Zusammenfassung Aufbauend auf einer früheren Arbeit [1] werden die theoretischen Zusammenh?nge bei der Massen?nderung von frei schwebenden Flüssigkeitstropfen in einem akustischen Positionierer hergeleitet und experimentell verifiziert. Die Darstellung umfa?t sowohl Temperatur?nderungen als auch Massen?nderungen bei der Verdunstung bzw. Kondensation von Tropfen unter verschiedenen Umgebungsbedingungen bzgl. Temperatur und relativer Feuchtigkeit. Neben reinen Flüssigkeiten mit Wasser als Standardflüssigkeit werden auch L?sungen mit dampfdrucksenkenden Zus?tzen berücksichtigt. Lebensdauer und Halbwertszeit der Tropfen werden im Zusammenhang mit technischen und wissenschaftlichen Anwendungen des akustischen Positionierers berechnet, gemessen und diskutiert. Die Arbeit erm?glicht die Planung und Optimierung von Experimenten mit kleinen, positionierten Tropfen bei Durchmessern zwischen 20 μm und 6,5 mm unter exakt definierten Umgebungsbedingungen mit geringem technischen Aufwand.     

Abscheidung leitender und nichtleitender Hartstoffschichten auf metallischen und keramischen Werkstoffen mittels Hochfrequenz-Plasma-CVD

Deposition of conductive and nonconductive hard coatings on metallic and ceramic materials by RF-PA-CVD Conductive titanium nitride and nonconductive aluminium oxide layers were deposited on conductive and nonconductive substrates by a RF-PA-CVD process. The influence of substrate material, pressure, plasma power and the components of the gas mixture on the layer properties was investigated. TiN coatings with a homogeneous structure could be deposited by using TiCl₄ as precursor. The properties of the layer are strongly influenced by the substrate material. An increasing pressure causes a faster deposition rate and a higher chlorine content. A lower chlorine content and at the same time a faster deposition rate can be achieved by increasing the r.f. power. Aluminium and aluminium oxide layers could be deposited on steel and Si₃N₄ substrates by using AlCl₃ as precursor in dependence on the CO₂ content in gas mixture. Higher CO₂ content facilitates the deposition of aluminium oxide.     

Korrosionsinhibierende Plasmapolymerschichten auf Stahluntergründen

Plasma polymeric coatings with inhibitory effect on steel surfaces The plasma based surface technique facilitates scientifically and technically, economically and ecologically interesting alternatives to traditional treatment procedures. From that the evolution of a new procedure for the improvement of the corrosion resistance of low‐alloy steel surfaces through ultrathin plasma polymeric coatings was a main topic at the iLF in the last years. After plasma based super cleaning process under oxidized conditions should be produced plasma polymeric coatings with a corrosion inhibiting / passivation effect. For this purpose corrosion inhibitor molecules are implanted into the normally electrochemically inactive coating during the process of the plasma based polymerization of silicon‐organic monomers. Through that it has been proved that the long‐term corrosion protection improves. Besides the surface of the produced plasma polymer shift can be modified by plasma‐technical procedures so that it shows also optimal adhesion promoter characteristics.     

Abscheidung von dekorativen Schichten mittels PVD‐/CVD‐Verfahren

Deposition of decorative coatings using PVD/CVD methods Decorative surface treatment of consumer goods has a cross‐sectional function, because of its many application in different industries. Beneath the classical methods as lacquering and electrochemical graftage, vacuum‐based methods – named with the acronym PVD and CVD – have definitely established itself up to now. For the last two methods, the future market will have a good growth potential in the field of decorative surface treatment. One reason for this is, that nowadays the product differentiation is very important for the marketing and this takes place more and more via “design” and to a lesser extent via the functionality of a product. The following article gives an overview about the possibilities of decorative coating deposition using PVD/CVD methods. Attention is paid on colour mechanisms, colour measurement as well as on resulting colours.     

Elektrolytische Abscheidung von Aluminium‐Magnesium‐Legierungen aus aluminiumorganischen Komplexelektrolyten

Electrolytic Deposition of Aluminium‐Magnesium‐Alloys from Electrolytes Containing Organo‐Aluminium Complexes The galvanic deposition of pure aluminium from fluoride‐containing electrolytes has been developed further and for the first time aluminium and magnesium have been deposited from a toluene‐solution of a halide‐free organo‐aluminium complex electrolyte. The rate of incorporation of magnesium can be controlled over a wide range by either adjusting the composition of the aluminium‐magnesium anode or by using separate aluminium or magnesium anodic circuits. The current efficiency for both anode and cathode approaches 100%. The resulting coating is optically attractive and, depending upon the magnesium‐content or the cathodic current density, can be formed as a dull or polished surface. Investigations using an electron microscope show that the surface, in contrast to that of pure aluminium, consists of spherical particles. The aluminium‐magnesium coating provides excellent protection against the corrosion of magnesium components. Electrochemical investigations using, for example 25% by weight magnesium incorporation, indicate a pronounced passivity interval compared to the alloy AZ91hp. In contrast to galvanic zinc‐plated and silicate‐sealed examples, cyclic corrosion tests on screws simulating 10 years of exposure, show no corrosion.     

Berechnung und Optimierung von Geometrie und Eingriffsverhalten von Zahnformen beliebiger Achslage

The main benefit, the economical manufacturability of traditional gear profiles, such as an involute, are no longer of major importance in times of computer-aided design and production. Due to existing modern production techniques standard and more sophisticated gear types can be produced with high precision and maintainable financial effort. Especially for non-standard gear types modern gear production systems ensure high quality and reliability to the operator with regard to flank and meshing geometry. Depending on the context of application different gear types have advantages and disadvantages concerning load carrying capacity, effectiveness or noise excitation. Developing an optimized gearing for the desired application is thus a complex and elementary goal within the design process.     

Abscheidung optisch,elektrisch und akustisch wirksamer Schichten mit dem Doppel‐Ring‐Magnetron

Numerous applications in optics, electronics and sensor technology require thin dielectric films. Conventionally they are deposited by evaporation, activated evaporation, rf‐sputtering or CVD‐techniques. This paper describes the deposition of such films using reactive Pulse Magnetron Sputtering. This technology not only enables a tenfold deposition rate compared to the conventional techniques but also offers new possibilities for influencing film growth. For example it is possible to alter film composition during deposition and hence to deposit complete optical systems without interruption of the plasma process. Furthermore the energetic bombardment of the growing film can be controlled in a wide range by the pulse mode and the pulse parameters. This can be used to either deposit very dense films by strong energetic bombardment or to deposit films at low thermal load onto temperature sensitive substrates. Examples of film deposition for laser optics, electrical insulation applications and surface acoustic wave devices show how these new technological possibilities advantageously can be used for creating innovative layer systems. Film deposition is carried out in stationary mode using a Double Ring Magnetron. This type of magnetron ensures film thickness uniformity better than ± 1 % on 8” substrates by the superposition of the thickness distributions of two concentric discharges.     

Optimalbereiche von Fluidenergiemaschinen-Pumpen und Verdichter

Based on a non-dimensional analysis of hydraulic and aerodynamic parameters and optimal working range of pumps and compressors is derived for the transport of liquids and gases. The total efficiencies that can maximally be achieved are determined as a function of the specific rotation speed n_q as characteristic parameter for turbo and displacement machines. Causal relationships for an extended “CORDIER”-diagram for the different types of machines are presented. The clear representation give indications of the possible applications of a particular machine in industry.     

Lichtbogen- und Plasmaspritzen von Sondermetallen

Arc and plasma spraying of special materials with high oxygen affinity Within the framework of the research work dealt with in this paper, metallic coatings of titanium, tungsten, molybdenum, tantalum and zirconium were produced on steel base material by the spray-deposition process. — The affinity of the molten special metals to reactive gases (particularly oxygen) is high, therefore. The spraying operation was carried out in an inert gas chamber. The equipment used to produce these metallic coatings comprised a two-wire arc-gun designed by the authors and a commercially available plasma-gun adapted to suit the test conditions. — In the case of all the special metals sprayed in this way the principal mechanism effecting adhesion must be seen to reside in a metallurgical interaction between base und sprayed metal. — Observations are discussed concerning structural peculiarities and embrittlement effects depending on the kind of shielding gas employed.     

Halbzeugoptimierung und Anwendungen von Thermoplastwickelverbunden

Optimation of semi-finished products and application of thermoplastic filament winding With an experimental, PC-controlled filament winding device (for thermoplastic materials) unidirectional semi-finished products (commingled yarns) are manufactured into long-fiber reinforced composites. The aim is to optimize this technology through the parameters of the hybrid yarns used. As reinforcing materials glass and carbon fibers and as matrix materials PA6 and PP are used. The influence of (glass fiber) size, glass fiber content, yarn type, structure and thickness of the hybrid yarn, as well as the type of reinforcing fibers are determined in the ring tensile test and the interlaminar shear test. The structure of the composite was investigated by REM, GPC, DSC and WAXS. Examples of a successful combination of long-fiber reinforced filament wound structures and the injection moulding technology are available.