In the present work, the microstructure, phase constitution, and corrosion behavior of binary Sn–xZn alloys (x = 5, 9 and 15 wt.%) were investigated. The alloys were prepared by induction melting of Sn and Zn lumps in argon. After melting, the alloys were solidified to form cast cylinders. The Sn–9Zn alloy had a eutectic microstructure. The Sn–5Zn and Sn–15Zn alloys were composed of dendritic (Sn) or (Zn) and eutectic. The corrosion behavior of the Sn–Zn alloys was studied in aqueous HCl (1 wt.%) and NaCl (3.5 wt.%) solutions at room temperature. Corrosion potentials and corrosion rates in HCl were significantly higher compared to NaCl. The corrosion of the binary Sn–Zn alloys was found to take place by a galvanic mechanism. The chemical composition of the corrosion products formed on the Sn–Zn alloys changed with the Zn weight fraction. Alloys with a higher concentration of Zn (Sn–9Zn, Sn–15Zn) formed corrosion products rich in Zn. The Zn-rich corrosion products were prone to spallation. The corrosion rate in the HCl solution decreased with decreasing weight fraction of Zn. The Sn–5Zn alloy had the lowest corrosion rate. The corrosion resistance in HCl could be considerably improved by reducing the proportion of zinc in Sn–Zn alloys.

In this work, the high temperature oxidation behavior of Al₇₁Co₂₉ and Al₇₆Co₂₄ alloys (concentration in at.%) is presented. The alloys were prepared by controlled arc-melting of Co and Al granules in high purity argon. The as-solidified alloys were found to consist of several different phases, including structurally complex m-Al₁₃Co₄ and Z-Al₃Co phases. The high temperature oxidation behavior of the alloys was studied by simultaneous thermal analysis in flowing synthetic air at 773–1173 K. A protective Al₂O₃ scale was formed on the sample surface. A parabolic rate law was observed. The rate constants of the alloys have been found between 1.63 × 10⁻¹⁴ and 8.83 × 10⁻¹² g cm⁻⁴ s⁻¹. The experimental activation energies of oxidation are 90 and 123 kJ mol⁻¹ for the Al₇₁Co₂₉ and Al₇₆Co₂₄ alloys, respectively. The oxidation mechanism of the Al-Co alloys is discussed and implications towards practical applications of these alloys at high temperatures are provided.

The fabrication of a polylactic acid (PLA)–carbonated hydroxyapatite (cHAP) composite material from synthesised phase pure nano-cHAP and melted PLA by mechanical mixing at 220–235 °C has been developed in this study. First, we report the cHAP nanocrystalline powder synthesis via a wet chemistry approach from calcium acetate and ammonium hydrogen phosphate precursors together with a crosslinking agent of polyethylene glycol, poly(vinyl alcohol) and triethanolamine. The calcination temperature of the cHAP was evaluated by thermal analysis, mass spectrometry and dilatometry measurements to be 680 °C. The X-ray diffraction showed that powders calcined at 680 °C are phase pure and crystalline. The formation of A- and B-type substituted cHAP was revealed by FT-IR spectroscopy. Further we present the preparation of the PLA–cHAP composite and surface microstructuring using the direct laser writing (DLW) technique. The depth of produced grooves was estimated to be around 25 μm and the width was 5–20 μm, the latter is laser power, translation velocity, and composition dependent. Scanning electron microscopy indicates that most evenly cut grooves with nanoparticles of cHAP homogeneously exposed to the surface were obtained for 5 and 10 wt% cHAP–PLA composites. The improvement of elastic modulus compared to the neat PLA was due to the cHAP, and the best results were obtained for composites loaded with 5% and 10% inorganic filler.

The article presents our Inquiry-Based Learning (IBL) activities in the project-based Science education of third graders (8–9-year-old pupils) in the Slovak Republic. Individual tasks of project assignment titled “Temperature Measurement” were conceived for “guided inquiry”. We also supported the IBL of pupils by interactive education strategy–Integrated e-Learning (INTe-L). The strategy was built on the role of interactive simulations and experimenting at the knowledge acquisition. The following INTe-L components were used: (a) on-site and remote experiments, (b) interactive simulations and (c) electronic study materials. The research was based the hypothesis that the project-based teaching of the topic “Temperature Measurement” using the IBL activities is significantly more efficient than traditional (instructivist) way of teaching. To verify the hypothesis, we carried out a pedagogical experiment on a sample of 60 respondents. The third graders were divided into two parallel groups: an experimental group (EG, 30 pupils) and control group (CG, 30 pupils). To get a relevant feedback, pre-test and post-test were developed and applied. The results attained in the EG were statistically processed, evaluated, and subsequently compared with those in the CG. The analysis of the results attained by the EG showed that their knowledge acquisition has been increased by 24% compared to CG. We have created a methodology for making simple scientific project assignments with the implementation of all components of the new integrated e-learning education strategy (real and real remote experiment, e-simulation, e-learning material). On a specific example of the topic “Temperature Measurement” in primary education, we have presented the possibility of using a “guided inquiry” in the implementation of individual experimental tasks. We have introduced a form of teamwork that allows to harmonize the teaching requirements with individual learning approach and helps to prepare pupils for planned work and independent knowledge acquisition and problem solving. The study has shown that complex IBL activities can be successfully applied at primary school 3rd grade level already. Our form of education with the wider use of modern information and communication technologies (ICT) was attractive for the learners and helped them to develop interdisciplinary relationships. The integrated e-learning has helped third grades to develop a deeper conceptual understanding of temperature and allowed them to prepare presentations to demonstrate their conceptual knowledge. The approach allowed pupils to gain key competencies in Science (discussion and presentation of results). It has also increased the pupils’ interest in Science in general and helped them to understand links between different subjects.