The work concerns a study of the properties of cold sprayed Ti coatings. This material is an attractive choice for many applications because it exhibits high strength-to-weight ratios, very good oxidation resistance, corrosion resistance and biocompatibility. Cold spraying is applied to deposit Ti coatings and elements as additive manufacturing process, however it needs higher critical velocity for deposition than other, more ductile metals. Nowadays nitrogen as cheap gas is used as working gas in cold spray process, however application helium as accelerating gas allows to obtain elements with higher strength. It allows to understand the mechanism of cohesion between sprayed particles. In carried out experiment Ti powder with angular shape was applied in the cold spraying process. The coatings were sprayed by means of Impact Innovations 5/8 system with nitrogen and addition of helium onto 7075 Al alloy. The investigations revealed that the cold sprayed Ti coatings with addition of helium as working gas exhibit better mechanical properties, lower porosity and roughness.

In this investigation, Ni-Al 2 O 3 powder mixtures containing different amounts of alumina were cold sprayed onto Al 7075 substrates. SEM analysis showed that the Al 2 O 3 particles were mainly distributed between elongated nickel grains although some were found fragmented on the surface due to impact with embedded Al 2 O 3 particles. All coatings exhibited high surface roughness while those with 40 wt% Al 2 O 3 had the best balance between embedded particle content and coating porosity. Nanoindentation tests revealed significant variations in hardness and Young's modulus over the surface of the coatings.

Nanostructured materials are of particular scientific interest because of their physical and mechanical properties, which are superior to those of conventional materials. They are more widely used in various industrial applications mainly due to decreasing production costs. The work is concerned with a study of the tribological properties of a HVOF sprayed composite of nanostructured WC12Co mixed with nanostructured Fe 3 O 4 , having the properties of solid lubricant. The coatings were sprayed by means of a Hybrid Diamond Jet system. A T-01 ball on disc tribological tester was used to study their resistance to wear and determine the coefficient of friction on the basis of friction force obtained in the course of continuous measurement at a set load. Result of investigations were compared with properties of coatings sprayed with standard WC12Co/ Fe 3 O 4 . The microstructures and compositions of the nanostructured powders and coatings were analyzed by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis. Their phase composition was studied using a Bruker D8 Advance diffractometer.

HVOF sprayed coatings are widely used to improve the service life of machines components. Influence of spraying parameters and different kinds of materials on coatings properties have been investigated in many works. Our investigations concern properties of HVOF sprayed two tungsten carbide coatings after applying electrospark deposition process (ESD). After finishing microstructure of sprayed coatings were changed by applying tungsten carbide electrode. Changes of microstructure and properties of the sprayed and post ESD process coatings were analysed with a scanning microscope JOEL JSM-5400. The element distribution was analysed with a microprobe ISIS 300 Oxford Instruments whereas phase composition was analysed by diffractometer D8 Advance (BRUKER). The roughness of coatings was measured with Talysurf-4, whereas Matuzawa MMT-X3A was used to study changes of their hardness. Ball on disc tester and dry abrasive rubber wheel tester were applied to estimate coefficient of friction and wear resistance of sprayed coatings before and after EDM process.

This study investigates the tribological properties of two HVOF-sprayed tungsten carbide coatings, each with a different content of cobalt, which were subjected to electrical discharge machining (EDM). It was found that the electrospark deposition of WC8Co over the HVOF-sprayed WC12Co and WC17Co coatingsresults in the formation of a homogeneous layer of tungsten carbide with a low cobalt content. The EDM layer is well bonded with the HVOF-sprayed coating as confirmed by the gradual change in the content of the elements in the coating and layer. The friction coefficients obtained for the two coatings with the EDM layer are very similar as their composition, microstructure, hardness, and surface roughness are approximately the same.

Undesirable changes in the coating composition can be reduced if plasma spraying is performed in a special chamber with a regulated atmosphere, the process being extremely costly, though. Another method allowing changes in the structure of coatings is thermal treatment. Numerous works present and discuss the results of the research into the influence of carburizing, nitriding, and laser or electron beam treatment on the properties of plasma sprayed coatings. This work concerned composite coatings obtained by plasma spraying of the blend of Al 2 O 3 -3TiO 2 and CuO powders, which were then reduced at an atmosphere of dissociated ammonia. Their chemical composition and morphology were determined by means of the EDS microprobe and the Joel 5400 scanning microscope respectively. It has been reported that the process of reduction contributes to the homogeneity of the coating, and that the modified structure contains Al 2 O 3 and Cu. Abstract only; no full-text paper available.

The aim of the research was to compare the size, shape and distribution of the NiCrBSi and Fe 2 O 3 powder particles. Of interest were the chemical and phase compositions of both the powders and structures obtained by plasma- or HVOF-spraying them. The experiments have shown that although the powders differ in structure and particle size, it is possible to use them to obtain composite coatings containing both ingredients. A phase analysis was conducted to study the different phase composition for both spray methods.

This paper assesses the effect of laser remelting on nickel-base coatings produced by thermal spraying. NiAl, NiCr, and NiCrAlMoFe layers are deposited on steel substrates via flame and plasma spraying and treated with a CO 2 laser operated at different power levels. The treated layers are evaluated based on microstructure, hardness profile, and wear resistance. Plasma-sprayed NiCrAlMoFe layers treated at a power of 1000 W exhibited the highest wear resistance. Paper includes a German-language abstract.

This paper assesses the abrasion resistance of plasma and HVOF sprayed WC-Co and Cr 3 C 2 coatings under dry friction conditions. It is observed that WC-Co layers produced by HVOF spraying have the most regular layer structure, the best abrasion resistance, and the highest hardness. Paper includes a German-language 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.

In the article the results of set of experiments concerning the changes in microstructure of plasma sprayed Al 2 O 3 , Cr 2 O 3 and W 2 C coatings of tribological test pieces obtained with use of locally applied laser beam treatment are given and discussed. The improvement of sprayed on coating layer adhesion to the steel base was ascertained and evaluated. The possibilities of the application of the described technology for development and production of slide elements of tribological joints are noticed.

This paper presents the results of a study on the scuffing behavior of thermally sprayed ceramic coatings. The progress of building up of seizure is related and evaluated for a set of ceramic coatings embodying a diversity of granulations of Al 2 O 3 TiO 2 and Cr 2 O 3 plasma sprayed on steel, the IHI8N9T steel and carbon-graphite when tested on a roller-block machine. The greatest antiscuffing resistance was recorded for Cr 2 O 3 /carbon-graphite pair. An analysis of regression approximating friction force was carried through.