Materialwissenschaft und Werkstofftechnik最新文献

Tires are one of the most important products in world transportation industry. The number of cars increases on the road and thus the amount of waste tires. Pyrolysis is one of the possibilities of recycling used waste tires. This work is focus on the characterization and application product (carbon black) from pyrolysis of waste tires in the polymer matrix. Carbon black from pyrolysis of waste tires is used as a filler in the polymer matrix in order to replace by conventional carbon black (N339 and N660). Thermal analysis, infrared spectrometry and Energy-dispersive x-ray spectroscopy analysis are used to determine the changes in the properties of waste tires pyrolysis carbon black compared to conventional carbon blacks. A scanning electron microscope is used to characterize the shape of the carbon black. After the application of fillers in the polymer matrix, the cure characteristics, reinforcing of the mixture and the mechanical properties are determined. Fraction adjustment of the carbon black from pyrolysis of waste tire shows a positive influence on the properties.

The replacement of glass fibres by cellulose-based fibres in printed circuit board (PCB) is motivated by environmental reasons since the use of biodegradable components from renewable sources will have a significative impact in the life-cycle assessment and sustainability evaluation of these materials. To study the potential of replacement of glass fibres by natural fibres in printed circuit board manufacturing we have used a finite element method (FEM) computational simulation methodology to evaluate the influence of key structural parameters on their thermomechanical properties, with the goal of predicting and quantifying its warpage at soldering process temperatures. In our work some printed circuit board (PCB) configurations have been selected and modelled using different natural fibres and compared with conventional printed circuit board systems, designated by flame retardant epoxy (FR4), that are made from glass fibres, epoxide resin and copper foils. The simulation results indicate that the printed circuit board assembly process, namely the number of layers, has a major influence on the key thermomechanical properties that were studied. Some optimized printed circuit board configurations were selected, based on the simulation studies, and the natural fibres were classified according to their potential to be used in the development of sustainable printed circuit board materials.

This study investigates the surface modification of polymer films, specifically polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polypropylene (PP), using diffuse plasma treatment with a focus on the “backside treatment” effect, where surfaces not directly exposed to plasma undergo measurable changes. The primary goal was to observe changes in surface properties, such as the contact angle of polyvinyl chloride, before and after plasma modification, and to analyze the extent of backside treatment. Diffuse plasma treatment effectively actiates polymer surfaces, altering their surface energy, wettability, and adhesion properties. Contact angle measurements on polyvinyl chloride indicated a significant reduction post-treatment, confirming successful surface activation. This enhancement in wettability is critical for applications demanding strong adhesion. Backside treatment, a key phenomenon in this study, was confirmed as a real and measurable effect. It was observed that even surfaces shielded from direct plasma exposure showed significant changes, which can influence the overall properties of the polymer films. This finding is essential for applications requiring uniform surface modification. Image analysis further supported these results, revealing alterations in surface morphology across different plasma treatment models. The extent of these changes varied depending on the polymer type, plasma parameters, and exposure model. In conclusion, this study demonstrates that diffuse plasma treatment induces significant surface modifications on polyvinyl chloride, polyethylene terephthalate, and polypropylene films. The backside treatment effect was proven to be a real and important factor in these modifications, with implications for industries requiring precise surface treatments. These findings suggest that controlling backside treatment could enhance material performance in various applications.

The work studies the interactions between polycaprolactone and hydroxyethyl cellulose in the blends with regard to the technology of preparation of the given material (twin-screw extruder), the effect of the compatibilizer ethylene-co-acrylic acid and the effect of the plasticizer (glycerin). The amounts of filler, hydroxyethyl cellulose mixed into the polycaprolactone were 0 wt.–% to 50 wt.–%. Opaque foils were prepared. The aim of the work is to prepare a material with satisfactory physico-mechanical properties for packaging materials using hydroxyethyl cellulose and semi-synthetic polymer from renewable sources. The effect of ethylene-co-acrylic acid compatibilizer and hydroxyethyl cellulose plasticization on morphology, mechanical properties (tensile strength, elongation of break, Young's modulus) and thermal properties are studied for the prepared blends. It is important to determine the optimal amount of glycerin for hydroxyethyl cellulose, as lower glycerin content may lead to a reduction in the mechanical properties of the blends.

The main motivation for this research work was the need to find new ways of managing process byproducts of combustion in a way that is safe for the environment and human health. The paper presents research confirming the applicability of the geopolymerization process to stabilize slags and ashes from municipal waste incineration plants. The article aims to assess the possibility of preparing geopolymer materials based on slags and ashes from the process of thermal transformation of municipal waste. The first stage of the work was the characterization of the raw materials used for research using microstructural tests (scanning electron microscopy, x-ray fluorescence and x-ray diffraction). The next stage was the synthesis of the geopolymer material based on the above-mentioned byproducts of the combustion process, including obtaining appropriate samples i. e., beams and cubes. The initial stage of work indicated the need to combine geopolymer materials with the content of slag and fly ash of post-process origin after the thermal transformation of municipal waste, mixed with another additive to improve the cohesion of the material. For this purpose, another product, which came from thermal transformation processes, was used - fly ash from the coal-fired power plant. Then, selected physical and mechanical properties of the prepared materials were determined, including: density, compression and bending tests and water absorption. The microstructure of the obtained materials was also characterized. The obtained results were assessed in terms of the possibilities of using new materials in the construction industry.

In the present work, zinc-6 % aluminium alloy, Galfan, is coated through the hot dipping technique on tensile bars made from cold rolled CRS 1018 steel to study the influence of Galfan coating on tensile properties of mild steel. The tensile results indicate that Galfan coating prepared by the hot dipping process reduces the ultimate tensile strength and yield strength of the substrate, whereas the elongation at failure is significantly increased. The microstructure of the as-rolled, hot-dipping coated, and other comparing specimens is observed by optical microscopy. Nano indentation is used to evaluate the variation of dislocation densities in the tested specimens. The analyses of the hardness-depth curves obtained from the nano indentation testing implies that the dislocation density of the coated steel might be lower than that of the uncoated specimen. The thermal energy received by the steel substrate during the heating stage of the hot-dipping process should be responsible for the recovery of the substrate, which leads to the reduction in dislocation densities and the arrangement of the dislocations into lower-energy configurations. As a result, the Galfan coating increases the elongation at failure considerably with a moderate decrease in strengths.

The as-cast copper-chromium (Cu−Cr) alloy has been manufactured through casting and compared with the cold forged and the heat treated ones. The heat treated forged Cu−Cr sample properties were 105 HV 1 and 257 MPa compared to those obtained in the case of as-cast pure copper whose properties are 92 HV 1 and 182.88 MPa. Accordingly, the average impact energy value obtained in the case heat treated forged Cu−Cr sample was higher than those obtained in other samples.

Sustainability in product development emphasizes the need for extended product lifetimes to minimize replacements and reduce resource consumption and environmental impact. This study investigates the impact of different thread manufacturing processes, cutting, rolling, and deep rolling, on the fatigue resistance of M12 threads fabricated from quenched and tempered chromium-molybdenum alloy steel. Fatigue tests conducted under cyclic tensile loading revealed that rolled threads exhibited superior performance, enduring higher stress levels without failure. Deep rolling significantly increased the fatigue strength compared to cutting, demonstrating its efficiency as a post-processing technique for enhancing durability. These findings highlight the sustainability and reliability of rolling as well as deep rolling processes and show that deep rolling is an effective post-processing technique for improving the durability of cut threads.

This paper deals with ideas for the use of 3D printing in spare parts management in the maritime industry. Although such ideas exist in the literature, there are still many issues that are not adequately addressed and researched. These include areas such as the influence of vibrations and waves on pressure, salt, humidity, etc. A numeric example is presented. Such problems can lead to faulty parts. Also, the speed of 3D printing is not yet acceptable for on-board applications. The paper presents the methodology for researching this issue. We also point out that all the required properties of filaments must be met in the complex maritime environment and that there is a need for new filaments for these applications.

Rutile titanium dioxide has stronger density and weather resistance than anatase titanium dioxide, the overall performance is better, but the required calcination intensity is also higher. In order to reduce calcination temperature and calcination time, lithium oxalate doped metatitanic acid was used to prepare rutile titanium dioxide. Adding 0 %, 0.15 %, 0.3 %, 0.45 %, 0.6 %, 0.75 %, 0.9 % and 1.05 % lithium oxalate (calculated as lithia) to metatitanic acid (calculated as titanium dioxide) containing 0.10 % phosphorus pentoxide, 0.20 % potassium oxide and 0.2 % calcined crystal seed respectively, calcined at 800 °C, 850 °C, 875 °C and 900 °C respectively. The results show that when the doping amount of lithia is 0.3 %, the maximum temperature is 800 °C, and the calcination time is 9 h, the rutile crystal style content in titanium dioxide products can reach 99.6 %, the grain size and particle morphology meet the performance requirements of titanium dioxide (R), and the calcination strength is significantly lower than that of industrial production above 1000 °C and 10 h to 12 h calcination time. Remarkable results have been achieved in energy saving and product quality. In addition, the hypothesis that the A−R phase transition is caused by the increase of mixing entropy of titanium dioxide system is used to explain the phenomenon that lithium ions effectively promote the phase transition of rutile.