Experiments for estimation of influence of microplasma parameters in ZrO 2 – coating properties were performed with using of fractional-factorial design of the experiments. Regression equations for determination of the parameters significance and a selection of conditions for a deposition of coatings with specified properties were obtained. Possibility of deposition of ZrO 2 - Y 2 O 3 coating with tetragonal phase content 90 wt.% and more without cubic phase content by microplasma spraying was shown. Conditions of microplasma ZrO 2 -coating spraying with high content of tetragonal phase (93-95%) and porosity (1,3-1,8%) were established. Measurement of microplasma sprayed ZrO 2 -coating spots has established that the spots have an elliptical shape. Size of major and lateral axis (and also sprayed hill altitude) depends on spray parameters, mainly on amperage and spray distance. Microplasma sprayed ZrO 2 -coating can be applied for repair of small local defects on thermo barrier coatings and a deposition of zirconia electrolyte layer in solid oxide fuel cell.

Development of thermal spraying of quasicrystalline coatings is connected with development of new powders for produced from alloyed quasicrystalline alloys. Powders of AlCuFe alloyed by Cr and Sc were produced by high – pressure water atomization of melt. Phase composition, microstructure, morphology, flowability of the powders were investigated. Resistance of powders to oxidation in air was studied using thermography. It was determined that doping of AlCuFe – alloy by 0,265 and 0,440 at.% Sc and by 8 at.% Cr significantly increases in them content of quasicrystalline phases. Annealing of AlCuFeCr at 550°C leads to transformation quasicrystalline phase into crystalline approximant of decagonal quasicrystalline phase.

Hydroxyapatite (HA) coatings were deposited onto titanium alloy substrate using the microplasma spray (MPS) technique. The fractional-factorial experiment design method was employed to study the relationships between MPS parameters (amperage, plasma gas flow rate, spray distance and powder rate) and characteristics of HA coatings (microstructure, morphology, content of crystalline and amorphous phases, texture). Influence of coating thickness and the deposited coating heat treatment were evaluated also. The results show some peculiarities of HA coating formation in conditions of microplasma spraying process.

The effect of methods and conditions of thermal spraying on structure and phase composition of coatings of the Al-Cu-Fe system alloy powders has been investigated. It is shown that the maximum ø-phase content of the coatings can be produced by the method of air-gas plasma spraying. In this case the thermal spray coatings inherit the multi-phase nature of initial powders. Preheating of the substrate prior to spraying allows the ø-phase content of the coatings to be increased.

This paper describes the development and evaluation of multifunctional coatings for outdoor parabolic antennas. The plasma-sprayed composite coatings provide corrosion protection, reduce solar heating, and improve the absorption of EM radiation at the edges of the antenna while impeding its flow in other areas. The coatings also reduce the impact of the support structure on antenna performance. Paper includes a German-language abstract.

Microplasma spraying has the potential to expand the range of applications for plasma spraying, particularly for the production of functional coatings. The low heat input on the substrate material allows small and thin-walled components to be coated without risk of overheating or deformation and with less powder loss due to the small plasma jet. This paper investigates the influence of various process parameters on the spraying of molybdenum, stainless steel, WC-Co, zirconium dioxide, and aluminum oxide using a microplasma system. Material consumption, plasma jet size, and layer structure are measured along with various aspects of particle behavior in the plasma jet. Paper includes a German-language abstract.

This work is devoted to the study of peculiarities of thermal sprayed coatings behavior under conditions of cavitation, as well as the elaboration of compositions of cavitation-resistant coatings and technology for their application with the aim of engine cylinders sleeves protection from cavitation-erosion destruction. The methods of arc metallization, flame and plasma spraying were used for coatings deposition. Powders of metal alloys and oxides, mechanical mixtures of nickel alloys with carbides, wires and flux-cored wires were applied as materials for thermal spraying. Method of magneto-striction vibration was used to determine the coatings cavitation resistance. A correlation between a bond strength of coatings and the character of their cavitation destruction was established. The best results were obtained in the case of using stainless steel wires and flux-cored wires using. Resistance of coated diesel engines sleeves was increased 1.6 times in comparison with sleeves without coatings. Semi-automatic line for arc metallization of diesel sleeves with a production of 600,000 sleeves per year was designed, build up and put into operation.

This paper provides results from experimental studies with regard to novel, thermally sprayed coatings for tribological applications, which consist of mechanical mixtures of cast iron powders (2.16% by weight C and 5.18% by weight Si) and solid lubricant (calcium fluoride or iron oxide) produced in an amount of 10 to 20% by volume. It was established that a basic phase of initial cast iron powder and detonation coatings is gamma-Fe and it is alpha-Fe in plasma coatings. Oxide inclusions which are products of cast iron oxidation are observed in coatings structure. Metallographic investigations showed an uniform distribution of solid lubricant inclusions in a metallic-matrix of coatings. Tribotechnical tests of coatings containing 20 vol. % calcium fluoride carried out in conditions of room temperature indicated that the best antifriction properties were obtained for coatings with calcium fluoride additions which were sprayed by supersonic air-gas plasma method. Paper includes a German-language abstract.

This paper describes investigation into the effect of the inorganic fillers on structural and physical-mechanical properties of polyethylene-based composite coatings produced by thermal spraying. A comparative analysis of the thermal spraying methods was carried out using spray polymers as an example. It was found that the powder particles made of aluminum and an Fe-B alloy, which were added to the polymeric materials, act as artificial crosslinking centers. This resulted in a decreasing grain size and an improvement in the physical and mechanical properties of the coatings. At low fill levels of the polymeric materials (up to 10% by volume), the degree of oxidation of the coating material decreased during spraying. Paper includes a German-language abstract.

Physical properties of coatings based on Fe-B, Fe-Ni-B, Fe-Cr-P-C, Fe-Ni-Si-B, Ni-P, Ni-Nb and Co-Fe-B-Si, deposited by the methods of flame, plasma-arc, and detonation spraying were investigated. The coatings have mostly the amorphous structure with the volume content of the amorphous phase equal to 75-95 %. Values of the distribution and temperature coefficients of electric resistance of the coatings, depending upon a method and conditions of spraying, as well as upon their treatment parameters, were determined. Comparative studies of these coatings and thin amorphous strips produced by the melt spinning method were conducted. The amorphous coatings of ferromagnetic iron and cobalt alloys are shown to be magnetically soft materials and are characterized by a high magnetic induction combined with a high magnetic permeability. As compared with the amorphous strips, Curie temperature of the amorphous ferromagnetic coatings is by 50-140 K higher and their anisotropy of magnetic properties is lower.

This paper examines the stress state of plasma-sprayed amorphous coatings of Fe-B with additions of Ni, Cr, and Mo. Internal stresses depend on the type of plasma gas used, the thickness and composition of the coating, and the material and temperature of the substrate. In this study, additional cooling of the substrate was found to be the most efficient way to reduce internal stresses. Amorphous coatings were also found to improve fatigue strength by as much as 25-30%, which is attributed to the formation of compressive stresses in the coating layers adjoining the substrate.

Microplasma spraying unit is characterised by small dimensions, low level of noise and emissions, low power consumption (kW*h/kg). The process provides deposition of coatings on small sized parts and components, including those with fine sections, this being unachievable with any other methods. This makes it possible to widen the scales of the application of plasma spraying and to produce different functional coatings. Microplasma jet has diameter 2-4 mm and length 30-50 mm. Velocities of different powder particles in conditions of microplasma spraying were measured. They amount 15- 60 m/s. Coating from iron-, nickel- and copper alloys were produced. Microstructure and properties of this coatings were studied. A real capability was demonstrated of microplasma spraying of narrow strips of 1-3 mm width with 0.2-0.5 mm thickness on the surface of stainless steel sheets of 0.5 mm thickness and of aluminum alloy of 1 mm thickness, as well as on the surface of 2-6 mm diameter cylindrical samples. The spraying spot has the form of an ellipse elongated along the vertical with 1.1-1.5 axes ratio, depending on the spraying conditions.