The aim of this work was to characterize ordered structures within cokes produced from single bituminous coals and from their blends. Three Polish coals of varying rank and caking ability were collected from the Krupiński, Szczygłowice, and Zofiówka mines, respectively. These coals were used for preparation of 19 blends: single (trivial blends), binary, and ternary ones. Cokes were manufactured in a laboratory scale using an apparatus with a Jenkner’s retort with a charge of 1000 g and heat-treatment temperature of 1000 °C. The X-ray diffraction (XRD) and Raman spectroscopy were used for the study. To determine the kind and size of ordered structures, the following parameters were discussed: interlayer spacing, d 002, crystallite stack height, L c, obtained from the XRD studies as well as the fractional contribution of ordered elements to all kinds of structures, and ratio of the amount of graphite structures (G type) to the amount of D2-type structures (less ordered than graphite), determined with Raman spectroscopy. The cokes produced from blends were treated as a compound system dependent upon properties of its components, single coal cokes. Additivity of the structural parameters of the cokes from blends was verified by the series model. Well-ordered structures, including the graphite-like ones, were found in all cokes studied. The highest degree of ordering was found in the single coke from very good caking Zofiówka coal. A similar structure was found in the cokes from binary and ternary blends of medium content of this coal of about 30–50 wt %. The preparation of cokes with well-ordered structures from blends of considerable lower concentration of the Zofiówka coal is promising, because the cost of these coke productions is lower than that of single coke from the Zofiówka coal. Discrepancy between the experimental data and those obtained from the series model confirmed mutual interactions between coals in a blend that affects forming of well-ordered structures in the cokes. This interaction was found to be the strongest in the blends with the content of the Zofiówka coal equal to 30–50 wt %.

This work discusses the development of the microstructure and mechanical properties of medium-carbon steel that contains silicon, aluminium and microadditions of Nb and Ti. Two cooling strategies were designed based on the thermodynamic equilibrium calculations and continuous cooling transformation diagram, which was determined for plastically deformed austenite. The cooling paths enabled the production of ferrite based and bainite based steels. The specimens were obtained via the thermomechanical rolling process with isothermal holding of steel at 450°C. Microstructure investigations were performed using light, scanning and transmission microscopy methods. The distribution and amount of retained austenite were determined using the electron backscatter diffraction technique, whereas transmission electron microscopy allowed the identification of the morphology of the γ phase. The amount of austenite and its carbon content were assessed using X-ray diffraction. Relations between microstructure and mechanical properties were formulated based on the mechanical stability of the retained austenite.

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The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.

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In the work it was demonstrated that the exploitative stability of edges from tool ceramics and sintered carbides coated with gradient and multilayer PVD and CVD coatings depends mainly on the adherence of the coatings to the substrate, while the change of coating microhardness from 2300 to 3500 HV0.05, the size of grains and their thickness affect the durability of the edges to a lesser extent. It was found that some coatings showed a fine-grained structure. The coatings which contained the AlN phase with hexagonal lattice showed a considerably higher adhesion to the substrate from sialon ceramics rather than the coatings containing the TiN phase. Better adherence of the coatings containing the AlN phase with hexagonal lattice is connected with the same kind of interatomic bonds (covalent) in material of both coating and ceramic substrate. In the paper the exploitative properties of the investigated coatings in the technological cutting trials were also determined. The models of artificial neural network, which demonstrate a relationships between the edge stability and coating properties such as: critical load, microhardness, thickness and size of grains were worked out.Keywords: Tool Materials, PVD and CVD coatings, Surface Treatment, Machining, Artificial Neural Network W pracy wykazano, że trwałość eksploatacyjna ostrzy skrawających z ceramiki narzędziowej i węglików spiekanych pokrytych gradientowymi i wielowarstwowymi powłokami PVD oraz CVD zależy głównie od przyczepności powłok do podłoża, natomiast zmiana mikrotwardości w zakresie od 2300 do 3500 HV0,05, wielkości ziarn oraz ich grubości w mniejszym stopniu wpływają na trwałość ostrzy. Powłoki wykazują drobnoziarnistą strukturę. Powłoki zawierające fazę AlN o sieci heksagonalnej wykazują lepszą przyczepność do sialonowego podłoża niż powłoki zawierające fazę TiN. Lepsza przyczepność powłok zawierających fazę AlN o sieci heksagonalnej związana jest z takim samym rodzajem wiązań międzyatomowych (kowalencyjnych) w materiale powłoki i ceramicznego podłoża. W pracy określono także własności eksploatacyjne powłok w technologicznej próbie toczenia. Zależności pomiędzy trwałością ostrza a własnościami powłok takimi jak obciążenie krytyczne, mikrotwardość, grubość i wielkość ziarna określono z zastosowaniem sztucznych sieci neuronowych.

In presented work we report results of simple and viable method for producing Au/CNT composites. Chemical composition and crystallographic structure of the Au/CNT composites was confirmed by X-ray diffraction measurements, while transmission and scanning electron microscopy were used to characterize the morphology of nanocrystals as well as the distribution of nanocrystals in the composite. The obtained particles with relatively small diameter (less than 9 nm) were found to be spatially well dispersed on the carbon nanotubes. The density of attached Au-nanoparticles is not sufficient, and cannot be improved by simple increasing gold loading.