Purpose – This paper aims to find an optimal surface treatment of commonly used polymeric substrates for achieve the high adhesion of printed structures. For this reason, the investigation of substrates surfaces from different perspectives is presented in this paper. Design/methodology/approach – The contact angle measurements as well as the roughness measurements were realised for the analysis of surface properties of investigated substrates. The impact of applied chemical agents for surface treatment onto the wettability is analysed for polyimide, polyethylene terephthalate and polyethylene naphthalene substrates. Findings – The results prove the correlation among wettability, surface energy and work of adhesion with respect to the theoretical background. The surface treatment of polymeric substrates by chemical agents, such as acetone, toluene, ethanol, isopropyl and fluor silane polymer, has a significant impact onto the wettability of substrates which affects the final deposition process of nanoinks. Originality/value – The main benefit of the surfaces’ investigation presented in this paper lays in surface modification by readily available chemical agents for optimising the deposition process nanoinks used in inkjet printing technology.

High speed steels have a leading position in the group of tool materials today in regard to their special properties. The article deals with the cutting life of tools, which cutting tips were produced from high speed steels. The test were realized at Faculty of Manufacturing Technologies TU Kosice with the seat in Presov, in collaboration with Institute of Material Research of Slovak Academy of Sciences in Kosice. As the method for tool-life investigation was selected the simple radial lathe-turning test. The measured values were statistically processed and submitted to the remoteness testing according to Grubbs. The results of the experiments are graphically presented as a dependence of cutting life on the cutting speed for five types of high speed steels. The base material for four of them was high speed steel STN 19 830 produced via powder metallurgy. It was modified by additional alloying elements, so in this way originated next variations of this steel listed above. Measured data were compared with the fifth type of high speed steel with similar chemical composition, but this type was produced via classical approach - by casting metallurgy. The know-how of the investigated relation will enable to the producers to make a good decision about what type of tool material should be used at the machining in specific conditions in order to achieve good quality of machined surface while achieving the required level of energy consumption.

The purpose of this study was to investigate (simulation of environment for salt treatment of roads in winter and the simulation of the environment of condensed exhaust gas) the galvanic corrosion phenomena which can exist in the construction coupling of cars. The electrochemical behaviour of the hot dip galvanized steel and aluminium alloy, stainless steel and aluminium alloy and stainless steel and silumin which were investigated by electrochemical methods in 3 % NaCl solution and in SEG solution. The open corrosion potential measurement was used to obtain the values of the potential for each couple. The measurement showed a greater bimetallic risk for hot dip galvanized steel with aluminium alloy, where there was ΔESCE > 500 mV and this couple is not suitable either for use in aggressive environment. Calculation of the rate of corrosion attack results from the determination of corrosion currents as measured by Taffel and Evans. The extent of corrosion damage was analysed by means of a light microscope. Keywords: bimetallic; aluminium alloy; stainless steel; silumin; exhaust gas; corrosion potential; electrochemical method;

The deposition of a thin (several tens of microns) protective coating in atmospheric conditions is a challenging task for surface engineering. The structural features and tribological properties of a particle-reinforced metal matrix composite coating synthesized on middle-carbon steel by air pulse-plasma treatments were studied in the present work. The 24–31 µm thick coating of “24 vol.% (TiC + WC)/Hardened steel matrix” was produced by 10 plasma pulses generated by an electro-thermal axial plasma accelerator equipped with a consumable cathode of novel design (low-carbon steel tube filled with “TiC/WC + Epoxy resin” mixture). The study included optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD, microhardness measurements, and dry “Ball-on-Plate” testing. The carbides were directly plasma-transferred to the substrate (steel of AISI 4145H grade) from the cathode without substantial melting. The hard (500–1044 HV) coating matrix consisted of 57 vol.% austenite (1.43 wt.% C) and 43 vol.% plate martensite was formed via carbon enrichment of steel from plasma flow. Additionally, a minor amount of oxide phases (TiO2, WO2, WO3) were dispersed in the matrix. As compared to substrate, the coating had a lower coefficient of friction; its volumetric wear was decreased by 4.4 times when sliding against hardened steel ball and by 16 times when sliding against SiC ball.