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 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.

This work presents the results of two-year-long pedagogical research, the aim of which was to demonstrate the applicability of the usage of a new strategy in education—Integrated e-Learning (INTe-L)—through its introduction into project-based physics teaching in Slovakia. The INTe-L strategy is built around the role of experiments and interactive simulations in knowledge acquisition and on the possibility of integrating scientific methods in education. The elements of INTe-L are the following: (a) real on-site and real remote experiments, (b) interactive virtual experiments (e-simulations) and (c) educational e-materials. The primary objective of our study was to determine the suitability of project-based teaching with INTe-L elements for the topic “Energy Sources”. The research was based on the following hypothesis: project-based teaching via INTe-L of the topic “Energy Sources” in physics is more effective than the traditional (instructionist) way of teaching. To verify the hypothesis, we performed a pedagogical experiment on a sample of 155 respondents in the 9th grade at two primary schools in Slovakia. The pupils were divided into two working groups: an experimental group (EG) of 85 pupils and a control group (CG) of 70 pupils. The pupils with worse grades were included in the EG. To get relevant feedback, pre-test and post-test studies and an interview were developed and applied. The results attained in both groups were statistically processed, evaluated and subsequently compared. A two-phase test with dispersion equality proved that differences in the pre-test scores in the EG and CG were not statistically significant. The differences in the final didactic test (post-test) results achieved by the EG and CG, on the other hand, were statistically significant and better scores in the EG were obtained. A positive change of pupils’ attitude in the EG towards physics after the execution of our project-based teaching was noted. The evaluation of the results attained by the pupils proved that the introduction of project-based teaching via INTe-L was an effective strategy to improve Physics teaching. As such, the implementation of this interactive strategy into the instructional education process at primary schools is recommended.

In the present work, the corrosion behavior of the Mg₂Sn alloy (Mg_66.7Sn_33.3, concentration in at.%) has been studied. The alloy was prepared from high purity Sn and Mg lumps by induction melting in argon. The alloy was composed of intermetallic Mg₂Sn with a small amount of Mg₂Sn + (Sn) eutectic. The corrosion behavior was studied by hydrogen evolution, immersion, and potentiodynamic experiments. Three aqueous solutions of NaCl (3.5 wt.%), NaOH (0.1 wt.%) and HCl (0.1 wt.%) were chosen as corrosion media. The alloy was found to be cathodic with respect to metallic Mg and anodic with respect to Sn. The corrosion potentials of the Mg₂Sn alloy were −1380, −1498 and −1361 mV vs. sat. Ag/AgCl in HCl, NaCl and NaOH solutions, respectively. The highest corrosion rate of the alloy, 92 mmpy, was found in aqueous HCl. The high corrosion rate was accompanied by massive hydrogen evolution on the alloy’s surface. The corrosion rate was found to decrease sharply with increasing pH of the electrolyte. In the NaOH electrolyte, a passivation of the alloy was observed. The corrosion of the alloy involved a simultaneous oxidation of Mg and Sn. The main corrosion products on the alloy surface were MgSn(OH)₆ and Mg(OH)₂. The corrosion mechanism is discussed and implications for practical applications of the alloy are provided.