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.

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.

An integrated approach was developed for investigation of thermal spray coatings with the amorphous-crystalline structure. The new approach combines methods of metallography, differential thermal and X-ray phase analysis, scanning electron microscopy and X-ray microanalysis. This makes it possible to reveal structural, phase and chemical heterogeneity, determine the degree of amorphization of coatings, temperature and heat of crystallization of the amorphous phase during heating. The new integrated approach was used to study amorphous-crystalline coatings of the Ni-P, Fe-Ni-B and Fe-B systems produced by thermal spraying.

Addition of CaSi 2 in steel melt leads to a decrease of oxygen content, an increase of the melt flow capability, an improvement of a metal ductility and weldability. For an estimation of CaSi2 and Si additions effect in conditions of thermal spraying composite powders were produced. A base material of these powders particles is nickel, nichrom and iron. CaSi 2 and Si are additional components of the powders (3-12 wt. %). Plasma coatings produced with using of these powders exhibit high density and adhesion. The coatings structure has a high grade of microcrystallinity with a decreasing size of lamels. Oxides content in the coatings decreases with an increasing of CaSi 2 and Si content in the composite powders, moreover this effect is more essential in case of CaSi2 addition. Addition of CaSi 2 and Si to Ni-base coatings increases a microhardness from 1900-2000 MPa to 2200-2850 MPa. In case of NiCr-base coatings this increasing is from 1800-2100 MPa to 2400-3500 MPa.

Stainless steel coatings were produced by supersonic air-gas plasma spraying method. Mixture of air and natural gas was used as a plasma forming gas. Powders of 304L and 316L stainless steels were used for plasma spraying. Thickness of coatings was up to 3 mm. Coating structure was studied. Dependence of oxygen content in coatings upon particle sizes and spraying conditions was established. Investigation of electrochemical properties of coatings was carried out by potentiostatic method. Corrosion potential and corrosion rate in sea water, hydrochloric and sulphuric acid solutions were determined.