Abstract In this paper, the morphology, the microstructure, the thermal stability ranges, the devitrification kinetics, and the hardness of amorphous detonation sprayed FeCrPC coatings are examined and compared with those of amorphous tapes of similar composition. Nanocoatings were made by heat treating the amorphous coatings. It is observed that thermal spraying (using the detonation gun method) produced coatings with an improved thermal stability of the amorphous component. Paper includes a German-language abstract.

Abstract In this paper, the flattening and the simultaneous solidification of a liquid particle when it hits a solid surface are described mathematically and numerically simulated in cylindrical coordinates on the basis of the Navier-Stokes equations. The heat transfer in the particle and in the substrate is simulated by solving the 2-D heat conduction problem, whereby hydrodynamic processes in the melted particle as well as pressure forces are taken into account. The particle solidification is investigated using the one-dimensional Stefan problem, taking into account the contact heat conduction at the boundary between particle and substrate. For numerical calculations, computational algorithms were created on the basis of the difference method, which were implemented in the form of an applied program complex. Paper includes a German-language abstract.

Abstract Ti-implants plasma-sprayed with a hydroxyapatite (HA) coating are widely used. When using an implant the coating quality is characterized by the presence of HA decomposition products and sprayed material structure. This paper investigates the properties of hydroxyapatite coatings and their dependence on the types of plasma spray. The types of hydroxyapatite decomposition on titanium substrates using plasma spray technology are optimized. Paper includes a German-language abstract.

Abstract Detonation sprayed coatings are nowadays applied on many kinds of heavily loaded sliding pairs and in the case high-speed machines. The basic problem in such applications lies in their durability and their scuffing resistance. Detonation sprayed coatings have a different in comparison with other junction surfaces microstructure and their behaviour in boundary condition let us better estimate possibilities of their application. This paper deals with the findings from experiments with regard to the seizure phenomenon when the friction pairing embodies an element with detonation-sprayed coatings. The progression of seizure is examined and evaluated for a number of aluminum oxide-13 titanium dioxide WC-Co 88/12 coatings that were applied to steel by means of detonation spraying. Paper includes a German-language abstract.

Abstract This paper aims to analyze the effect of the nature of the core material, the geometry of the buffer rods, as well as the nature and thickness of the cladding material on the ultrasonic propagation properties of these guidance components. The development of ultrasonic waveguides was studied in order to address the need for operation under strict conditions. The effects of the composition and thickness of the cladding as well as the type and geometry of the core were investigated with straight and tapered aluminum oxide and 1018 steel rods for the core and with plasma-sprayed aluminum oxide or aluminum oxide-chromium oxide for the coating. The results show that tapered plated buffer rods perform better than their unclad straight counterparts. They also indicate that the addition of chromium oxide to aluminum oxide is promising in a broader temperature range in which these conductors can be used. Paper includes a German-language abstract.

Abstract Silicates represent a broad group of industrially important ceramic materials. The only silicate that is widely used for plasma spraying is zirconium silicate. Other silicates are generally not used, although they can offer interesting application properties. This paper presents results with other silicates: synthetic wollastonite, stoichiometric mullite, cordierite, and steatite. The input materials were produced in selected sizes from ceramic in industrial quality and applied with the water-stabilized plasma spray system PAL160 to form free-standing panels. The morphology of the microstructure, the thermal expansion, the bulk and filling densities, the open and closed porosity, the phase, and the chemical changes were evaluated. Paper includes a German-language abstract.

Abstract This paper examines an aluminum oxide coating plasma-sprayed onto a substrate made of high-quality stainless steel by means of light microscopy, X-ray diffractometry, and scanning and transmission electron microscopy (TEM). The aim is to determine the phases that form preferentially at the transition. It is observed that high amount of corundum phase was found in a plasma sprayed white alumina coating. XRD phase analysis of the coating indicated that all three major alumina phases were present: alpha-, gamma-, and delta-aluminum oxide. Further development in the field of TEM sample preparation is required in order to obtain larger electron-permeable surfaces, since it is not clear whether the alpha-aluminum oxide found at the transition is in the form of a spatter or a grain introduced by sandblasting. Paper includes a German-language abstract.

Abstract This paper aims to characterise and to study several Ni-based alloys bond coatings and to determine the very best spraying conditions to achieve FGMs by means of a single gun with independent powder feed. First, adhesive layers made of NiCr, NiAl, and NiCrAlY were sprayed onto a steel substrate. All samples were tested by isothermal oxidation at 1000 deg C. The oxides formed and the conversions of the original oxides were studied on the samples and characterized using scanning electron microscope and EDS. It is observed that the study of three different bond coating sprayed with the same conditions reveals the best performance for the NiCr coating. Paper includes a German-language abstract.

Abstract Due to high kinetic energy of an impinging droplet a strong elastic deformation of the substrate and the formation of its curvature occur which influence the dynamics of the droplet flattening (particularly the thickness and the diameter of a splat) and a pressure formed upon the droplet impact. This paper involves investigation of these phenomena and the development of the simple analytical formulae needed by the engineering practice which enables to estimate the influence of the substrate deformation on the droplet flattening and the high pressure generation. The analytical results are obtained with regard to the variation of the splash properties and the pressure that arises when the droplet is flattened during thermal spraying. The splash curvature caused by the drop impact is taken into account. The paper also analyzes the role of surface effects. The results obtained show good agreement with the experimental observations. Paper includes a German-language abstract.

Abstract Wetting between the spreading droplet and the substrate plays an important role in the droplet flattening because it affects not only the surface effects but also the contact thermal resistance at the splat-substrate interface which is an important parameter for the development of the coating structure. In this paper, analytical formulas are determined which show the influence of wetting phenomena on the thickness or the radius of the splash, on the pressure developed upon drop impact and on the splash porosity. An effect of surface tension on the flattening parameters is investigated. The results obtained show good agreement with the experimental data. Paper includes a German-language abstract.

Abstract This paper aims to measure the residual stresses of plasma sprayed oxide ceramic deposits using the X-ray diffraction method and measure the Young’s Modulus in specially designed four-point bend test device. Aluminum oxide and chromium oxide coatings are made with a water stabilized plasma spray gun. The paper analyzes the microstructure and the phase composition. The X-ray diffraction method is used to determine residual stresses on the layer surfaces. The same method is used for the local measurement of surface tensions in a four-point bending device built into an X-ray diffractometer. This device also enables the force applied and the specimen deflection to be measured. Effective modules of elasticity are determined from the gradient from load to deflection during bending. The results of the tension measurements and the values calculated from the applied force are compared. Paper includes a German-language abstract.

Abstract This paper aims to fabricate wear resistant composite coatings on light metal substrates which also exhibit low friction coefficients. It demonstrates that combined ceramic polymer coating systems are a powerful concept for industrial applications where high wear resistance, creep resistance and compressive strength as well as low friction coefficients are required. The results show that, under the specific experimental conditions used, the titanium dioxide layer in connection with the applied lubricant lacquer showed better performance than the mixed aluminum oxide/titanium dioxide layers. Paper includes a German-language abstract.

Abstract Thermal spraying offers the possibility of applying functional metal, ceramic or cermet coatings to components with different geometries and materials and significantly improving their thermal, mechanical, and chemical properties. The performance in operation as well as failure due to deformation, cracks, and delamination are mostly determined by the internal stress state within the coated components. This paper reviews coating developments on light metal and glass substrates, sprayed with different atmospheric plasma spray process spray parameters are reviewed. The results show that from the numerical and experimental residual stress analysis, the injection parameters can be influenced individually. This leads to optimized residual stress states in the coated components with regard to the expected operating loads. Paper includes a German-language abstract.

Abstract This paper presents the results of metal dielectric multilayer structures based on aluminum alloys and several oxide ceramics respectively. It investigates thermomechanical and dielectric properties with regard to the use of different powders for thermal spraying as well as a high and a low energy gun for atmospheric spraying. The experimental work of this study is divided into two main parts: the selection of materials and the development of promising coating systems and the manufacturing and testing of novel ozonizer tubes. The investigated coating systems are analysed focusing the application in ozonizers. Therefore, a metallic electrode, an oxide ceramic and the dielectric properties of the metal-ceramic-composite are analysed. Finally, the appropriate metal-ceramic composites are tested in an ozonizer. Paper includes a German-language abstract.

Abstract This paper investigates the microstructure, bond adhesion, and high temperature and thermal fatigue performance of plasma-sprayed chromium carbide, nickel-chromium coatings after continuous exposure at high temperature inside a combustion chamber that simulates the extreme conditions existing in different industrial applications. Experiments on high temperature behavior under oxidative and neutral atmospheres and thermal fatigue tests are carried out in a test combustion chamber. Finally, the adhesion between the substrate and the coating layer is assessed using tensile tests. The paper discusses the results with special consideration of the microstructure development through the heat treatment. Paper includes a German-language abstract.

Abstract This paper reviews the results of thermal spraying on the magnesium alloy AZ 91. By plasma, arc and HVOF spraying various metal based alloys were used as coating materials. The layers were investigated with regard to microstructure, bonding and corrosion resistance. Paper text in German.

Abstract Dispersion welding can be used both for repairing worn machine parts and for atomization on surfaces with novel components. Knowledge of the temperature changes during melting and the shifting process of the scattered layer are important for the exact technological design, because the expansion and stress processes can be calculated from this data. In this paper, the expansion calculations are presented, which were determined on the basis of the measurement data during induction melting. Paper includes a German-language abstract.

Abstract In this paper, the influence of the plasma spray parameters on the mechanical properties of Ni-50% Cr coatings is systematically studied using the method of orthogonal regression test planning. The target properties include adhesive strength, micro-hardness, grinding wear, and erosion wear. The three spray parameters used as variables are plasma arc current, Ar flow rate, and spray distance. From the regression formulas, it is concluded that the effects of the spray parameters on the properties largely depend on the individual properties. Paper includes a German-language abstract.

Abstract After a short description of the rod flame spray method some european products of rod flame spray guns will shown. Some properties of the most used layers of oxide ceramic materials will be introduced. Several applications shows the versatility of this technique. Paper text in German.