Seznam abstraktů 2026: POSTEROVÁ SEKCE D

In the oil and gas industry, the repair of worn drilling tools often involves the deposition of WC-based coatings using hardfacing techniques. In this study, a damaged WC-based metallic matrix composite was restored through a WC-NiCr coating deposited by the Tungsten Inert Gas (TIG) hardfacing process. Microstructural analysis revealed significant elemental diffusion across the interface between the hardfacing layer and the consolidated substrate, particularly involving chromium and copper. This interdiffusion promoted the redistribution of WC particles near the interface, thereby improving metallurgical bonding. Furthermore, partial fragmentation and dissolution of WC particles within the NiCr matrix were observed, leading to the formation of secondary carbide phases such as Cr₂₃C₆, W₂C, and Ni₂W₄C. These microstructural transformations significantly strengthened the metallic matrix, resulting in an approximate twofold increase in microhardness compared with the as-infiltrated material.

This paper examined the suitability of thermally sprayed coatings for high-temperature corrosion protection. The coatings' resistance to abrasive wear and erosion, which, along with corrosion, are inherently damaging factors in power boilers, particularly fluidized bed boilers, was also determined. The theoretical section presents the need to modernize power generation due to the increasing requirements for operation in supercritical conditions and the consequent accelerated wear of power unit components. The system's operational scheme and the mechanisms that damage components, primarily the power boiler, during the energy production process are described. The broad application possibilities of protective coatings and their manufacturing processes are then discussed. In the research section, samples of thermally sprayed coatings were prepared by arc spraying onto S235 structural steel. Erosive wear tests were conducted at 30° and 90° angles, and abrasive wear tests were also conducted. High-temperature corrosion was conducted on ashes from biomedical waste incineration and power plant ashes under simulated power-boiler operating conditions. The results were analyzed using a stereomicroscope and a scanning electron microscope (SEM).

A special group of paint systems is paint coatings for military applications, mainly for camouflaging weapon systems and military equipment. Paint coatings are fundamental to camouflage - they conceal vehicles/objects in the optical range, both in visible light (VIS) and near-infrared (NIR). The main task of effective camouflage is to eliminate features that may cause the object to be differentiated from its surroundings, i.e., those that make it possible to distinguish one's own assets from the background, such as color, shape, size, gloss, and texture.
Numerous research centers worldwide are involved in the study of laser surface modification. By controlling laser parameters such as the amount of power, scanning speed, and pulse duration, it is possible to form coatings with different surface properties, including surface geometry, microhardness, stress states or resistance to wear. The paper analyzes the influence of selected laser-processing parameters on the removal of paint coatings used for special applications in armaments and military equipment. By controlling the laser processing parameters, i.e., power density, feed rate, pulse frequency, and duration, the best processing conditions were selected at which masking coatings were removed. To clean the surface, laboratory tests were carried out to remove the paint coating using the surface-layer cleaning technique with a picosecond laser TruMicro 5325c emitting UV radiation (343 nm). As part of the research, measurements of the surface geometric structure, hardness, and adhesion, as well as observations of the microstructure, were made. Numerous research centers worldwide are conducting studies on laser surface modification. By controlling laser parameters such as power, scanning speed, and pulse duration, it is possible to form coatings with different surface properties, including surface geometry, microhardness, stress states, and wear resistance.
The paper analyzes the influence of selected laser-processing parameters on the removal of paint coatings used for special applications in armaments and military equipment. By controlling the laser processing parameters, i.e., power density, feed rate, pulse frequency, and duration, the best processing conditions were selected at which masking coatings were removed. To clean the surface, laboratory tests were carried out to remove the paint coating using the surface-layer cleaning technique with a picosecond laser TruMicro 5325c emitting UV radiation (343 nm). As part of the research, measurements of the surface geometric structure, hardness, and adhesion, as well as observations of the microstructure, were made.

Magnesium alloys require surface treatment to improve their corrosion resistance due to their high chemical reactivity. Plasma electrolytic oxidation (PEO) is a widely used method, with current research mainly focused on phosphate-based and silicate-based electrolytes. In this study, a phosphate-based electrolyte enriched with titanium dioxide (TiO₂) particles was used to enhance the protective properties of the PEO coating formed on AZ31 magnesium alloy. The influence of surface pre-treatment (grinding vs. laser ablation) on coating formation and corrosion behaviour was investigated.

Laser pre-treatment modified the surface morphology and influenced subsequent coating growth. SEM analysis revealed that the laser-treated surface promoted the formation of a more compact PEO layer. The structural differences were reflected in the electrochemical response, where the laser + PEO combination exhibited improved corrosion resistance after 168 hours of exposure. The results indicate that laser surface modification is an effective approach for enhancing the corrosion durability of TiO₂-doped PEO coatings.

Surface modification of polymeric materials represents an effective strategy for tailoring their properties without the need to synthesize new material systems, thereby significantly expanding their application potential. In this context, advanced plasma technologies have emerged as a promising tool for the controlled deposition of functional coatings on polymer substrates. The present study focuses on the deposition of thin films on high-impact polystyrene (HIPS) using pulsed direct current magnetron sputtering. Targets based on titanium, silicon, zirconium, and nickel were employed, while different magnetron power duty cycles were applied (45/20/20/15%, 100/100/100/100%, and 45/20/20/100%). Characterization of the modified surfaces includes analysis of surface morphology, the chemical composition, and the height roughness parameters of the deposited films. Tribological properties were assessed using the Ball-on-Flat method, showing a reduction (15.4-21.1%) in the dynamic coefficient of friction compared to the reference material. In addition, surface wettability was analyzed, revealing an increase in the contact angle after thin film deposition; the highest increase (22.6%) was observed for the sample prepared at a duty cycle of 45/20/20/15%. The results confirm that pulsed DC magnetron sputtering is an effective approach for enhancing the functional properties of polymeric materials.

This study aims to evaluate the corrosion behavior of metallic materials used in fire sprinkler systems under actual service conditions and to investigate the correlation between environmental factors and corrosion characteristics.
Failed field components were collected and subjected to structural and chemical analyses to identify the root causes of corrosion. To investigate corrosion behavior, macroscopic surface inspections were conducted using a stereo microscope, followed by detailed surface and microstructural analyses using scanning electron microscopy and energy-dispersive X-ray spectroscopy. These techniques were employed to qualitatively and quantitatively characterize oxide formation and corrosion products on the metallic surfaces.
The results indicate that corrosion initiation predominantly occurred at the junctions between metal pipes and sprinkler heads. Three distinct corrosion mechanisms were identified depending on the affected regions: (1) pitting and crevice corrosion, (2) intergranular and transgranular corrosion, and (3) erosion corrosion.
Based on the analytical results, corrosion initiation and propagation mechanisms at the pipe-head interface were systematically derived. The findings of this study provide valuable field-based corrosion behavior data under real operating conditions, and the establishment of preventive maintenance strategies for enhancing the reliability of sprinkler systems.

This study presents the results of a comprehensive evaluation of selected methods for enhancing the tribological wear resistance of forming tools made from wear-resistant steels, used in the extrusion of ceramic roof tiles. The research addressed both the selection of tool materials and surface engineering techniques. Microscopic analyses (XRD combined with SEM-EDS) granulometry, and thermogravimetric analysis (TGA) were performed on the plastic mass, composed mainly of clay and sand. Comparative wear tests were conducted using a laboratory-scale “rotating bowl” method, where the ceramic mass served as the abrasive medium. Four material variants were selected for testing: Hardox 600, hardened NC11LV, nitrided NC11LV, and C45 with a hardfaced EuTroLoy 16006A layer.Microstructural analysis of the plastic mass allowed identification of hard fractions responsible for accelerated tool wear. Results of the rotating bowl test showed that the C45 hardfaced sample exhibited the highest wear resistance, based on 3D-scanned geometric material loss perpendicular to the surface. For final verification, forming tools made from all analyzed materials were tested under industrial production conditions. Each tool operated for 170 hours and was then analyzed for material loss using 3D scanning. The results indicate that under operational conditions, the tool made from NC11LV with an additional nitrided layer exhibited the best performance, with critical areas showing material loss below 0.50 mm. The outcomes of this comprehensive study enable a more informed selection of materials and surface treatment technologies, contributing to the optimization of operational parameters of forming tools and improving their durability in ceramic tile production.

The surface quality of steel sheets for the production of components of automobile locking systems can affect their damage during long-term use. The paper discusses the results of partial experimental tests of selected steel sheets of the S420MC and S500MC grades recommended for this production. These are microalloyed high-strength thermomechanically rolled HSLA steel sheets with thicknesses of 2.3 µm and 2.0 µm. The chemical composition of both steels was experimentally determined, Vickers hardness measurement at HV10 load, EN ISO 4287 tensile test according to the ČSN EN ISO 6892-1 standard, surface roughness measurement by contact profilometry according to the ČSN EN ISO 4287 standard, metallographic analysis. The results showed higher hardness of steel of the lower strength class S420MC compared to steel S500MC. This apparent contradiction is explained by the different microalloying strategy of both materials, where S420MC steel is strengthened mainly by precipitation of vanadium carbides and carbonitrides / VC, V(CN)/, while in S500MC the grain refinement mechanism with precipitation of niobium carbides and carbonitrides / NbC, Nb(CN) prevails. The surface roughness of the steel sheets differs significantly. The above-mentioned conclusions of partial experimental tests predict the possibility of fatigue fractures of the locking systems, which will be experimentally verified subsequently.

Small Modular Reactors (SMRs) based on Lead-cooled Fast Reactor (LFR) technology represent a promising option for future nuclear energy systems due to their enhanced safety features and efficient fuel utilization. A critical challenge for SMR‑LFR deployment is the long-term compatibility of structural materials with liquid lead coolant under high-temperature and varying oxygen conditions.
This work presents a comparative investigation of the corrosion behavior of two candidate structural materials, the ferritic-martensitic steel T91 and the austenitic stainless steel 316L. Both materials were studied in as ¬ received state to assess the corrosion performance/behavior of the reference material. To enhance corrosion resistance, material samples coated with a protective layer based on AlTi with tungsten (W) were investigated. Exposure experiments were conducted in liquid lead at a temperature of 520 °C under controlled low-oxygen and high-oxygen concentrations in the melt, simulating/ to simulate relevant operating regimes of SMR‑LFR systems.
The material degradation was evaluated with respect to corrosion mechanisms, formation and stability of protective oxide layers, dissolution phenomena, and coating integrity as a function of oxygen concentration in liquid lead.
The results provide deeper insight into the relative performance of T91 and 316L steels, as well as the effectiveness of AlTi+W coating under different oxygen conditions at elevated temperature. The findings contribute to the optimization of material selection and surface protection strategies for structural components operating in liquid lead-cooled SMR systems.

Vitreous enamel coating is the final product of physicochemical reactions in the process of heat treatment of glass of complicated chemical composition with other components of inorganic nature, combining the properties of glass and ceramics with the ability to adhere to a metal substrate. Its main function is to protect the underlying metal against corrosive environments and high temperatures. At the same time, it fulfills an important aesthetic and decorative role. Vitreous enamel coating is an environmentally friendly type of inorganic coating, especially in contact with drinking water and food. The enameling technology itself integrates a wide range of technical and technological knowledge. Enameling technology represents an interdisciplinary educational tool connecting technical and art education with natural sciences. The paper analyzes its didactic potential, identifies the main barriers to implementation and presents the results of research focused on teachers' attitudes. Teachers who have completed the pilot course in enameling show a significantly higher level of willingness to introduce this innovation, especially in primary and secondary school teaching, and thus pass on information about enameling technology and its use in industrial and non-industrial practice to future generations of humanity.