The mill scale is a waste from the iron and steel industry. Due to the high content of iron in the form of oxides, it is an attractive material for the recovery of metallic iron by reduction. The product of mill scale reduction is an iron with a very extended surface and a high affinity for oxygen. The smaller iron particles are, the easier it is for spontaneous rapid oxidation, which can be linked to pyrophoricity. This article presents results of experiments using the TG/DTA thermal analysis method aimed at verifying the possibility of recovering iron from the mill scale by a reduction with carbon monoxide at 850 °C, 950 °C, and 1050 °C, taking into account the phenomenon of secondary oxidation in contact with oxygen from air at temperatures of 300 °C, 350 °C, and 400 °C. Two forms of mill scale were used for tests, in the original state and after grinding to develop the surface.

Intermetallic phases represent a group of materials of unique properties. Many of those materials have found practical application, whereas others are still intensively examined. There are ten stable intermetallic phases in Al–Zr system, among which few are prospective materials to work at elevated temperature, nuclear reactors, etc. On top of that, researches are focused on obtaining amorphous phases, nanoparticles and zirconium-based pressure pipes covered with aluminum. As a result, better understanding of thermal effects accompanying those compounds formation becomes crucial. In this paper, solution calorimetry method was used for determination of formation enthalpy Δ_fH of intermetallic phases from Al–Zr system at room temperature (298 K). Experiments were conducted using test station built by author. Material used as bath was aluminum. Additionally, alloys preparation methodology was described and presented. Calorimetric measurements were taken on phases: Al₃Zr, Al₂Zr, Al₃Zr₂, AlZr, Al₂Zr₃, AlZr₂ and AlZr₃. Heat of dissolution of zirconium in aluminum bath at temperature 1073 K was determined experimentally and was equal to − 244.5 ± 5.4 kJ mol⁻¹. Obtained results of enthalpy of formation were summarized and compared with the literature data.

Technical copper alloys with tin are commonly named bronzes. Modern tin bronzes used in industry contain between 1 and 9 at.% of tin. Those alloys are used mostly for mechanical working. An increase in tin content in bronzes cooled in standard conditions results with appearance next to heterogeneous structure α and also other structures, including adverse phase δ. In ancient times, bronzes with tin content up to 14 at.% were used in order to manufacture ornaments or items used for everyday life such as singing bowl. An analysis of discussed bowl structure indicated dominant \(\beta_{1}^{'}\) and \(\gamma_{1}^{'}\) martensite phase, which is an evidence of quenching in order to preserve the high-temperature β and γ phase structure. The main goal of this work was to obtain high-tin bronze structure corresponding to phases identified in singing bowl. On the basis of chemical composition and structural analysis of the singing bowl, a binary technical alloy was prepared by induction melting process. On such prepared alloy, a differential thermal analysis was performed in order to determine the presence of phase transitions. Based on results of thermal analysis, the temperature ranges and cooling conditions of heat treatment were investigated in order to perform structural analysis. Additionally, the structure of the alloy was analyzed in context to achieve a similar martensite phase as a matrix with α secondary phase.

Electropolishing is electrochemical method used in metal working that has a vital role in production of medical apparatus, in food or electric industry. The purpose of this paper is to determine optimal current parameters and time required for conducting electropolishing process from the perspective of changes of surface microgeometry. Furthermore, effect of different types of mechanical working used before electropolishing on final surface state was evaluated by observation in changes of topography. Research was conducted on electrolytic copper and brass. Analysis of surface geometry and its parameters (Ra, Sa) was used as criterion describing efficiency of chemical electropolishing. Results of the experiment allow for current parameter optimization of electrochemical polishing process for selected non-ferrous alloys with preliminary mechanical preparation of the surface.

The calorimeter presented in this paper is constructed under supervision of authors. The most substantial innovation of construction of the device was introduction of intermediate container with ten sockets. As a result the calorimeter is used for determination of enthalpy of formation for alloys in a wide range of temperature (up to 1,400 K). As an example results from alloys from the Ni–Al–Cr system are presented, they are aimed to determine directly γ′ / γ′ + γ / γ phase boundaries with use of this “in situ” calorimetric method. Precise indication of phase boundaries is crucial for determination of phase diagrams.

The aim of the study is characterization of high-temperature oxidation behavior of new Co-based superalloys by thermogravimetry (TG). The following alloys have been taken into account: Co–9Al–9W, Co–20–Ni–7Al–7W, Co–10Al–5Mo–2Nb and Co–20Ni–10Al–5Mo–2Nb (at.%). The thermogravimetric analysis was carried out in the temperature range 40–1200 °C of heating rate 5° min⁻¹. The investigation was performed using the thermal analyzer NETZSCH STA 449 F3 Jupiter. TG–DTG plots showed oxidation behavior up to 1200 °C and indicated the temperatures of further isothermal oxidation examinations. The oxidation behavior of basic Co–9Al–9W (at.%) alloy was compared to W-free Co–10Al–5Mo–2Nb and Co–20Ni–10Al–5Mo–2Nb (at.%) alloys. The obtained data showed different oxidation behavior dependably on the type of alloying elements. Moreover, the effect of Ni addition on oxidation performance was determined. The scales grown on Co-base superalloys after thermogravimetry were evaluated by means of scanning electron microscopy and energy dispersive spectroscopy.