The effect of 0.2% addition of Mg, Co and Ce to 99.9% cast aluminium was studied by evaluation of changes in microstructure and mechanical properties. The microstructure was analyzed by scanning electron microscopy and transmission electron microscopy. The Al99.9 alloy contained only Al-Fe-Si phase particles. Similar Al-Fe-Si particles were observed in alloy with 0.2% Mg addition, because this amount of magnesium was fully dissolved in the solid solution. The addition of cobalt resulted in the formation of Al9.02Co1.51Fe0.47 phase particles assuming the shape of eutectic plates. The electron backscattered diffraction map made for the alloy with 0.2% Co addition showed numerous twin boundaries with distances between them in the range from 10 to 100 µm. The addition of cerium was located in the grain boundary area. Cerium also gave rise to the formation of two types of particles, i.e. Al4Ce and Al-Ce-Fe-Si. The Al-Ce-Fe-Si phase is a nucleation site for the Al4Ce phase, which forms eutectic plates. The results showed that the introduction of additives increases the mechanical properties of the cast materials. The 99.9% cast aluminium has a hardness of 16.9 HB. The addition of 0.2% by weight of Mg, Co, Ce increases this hardness to 21.8 HB, 22.6 HB and 19.1 HB, respectively.

The work presents results of research on the influence of micro materials on the thermal conductivity λ of gypsum. In the research, cellulose-based polymer and aerogel were used as the modifying micro materials. For the purpose of measuring the thermal conductivity, a non-stationary method was used based on the “hot wire method”. A very precise set of devices for measuring and recording the temperature of the heating wire was used. In the presented solution, a single measurement took only one minute. Measurements were recorded with the help of a computer measuring system, with a sampling time of 0.01s. During the 60-second-long test, 6000 measurements of the heating wire temperature were collected. A decrease of the thermal conductivity and density of hardened gypsum with added micro materials was observed due to modifications of the structure of the final product. Experimental values of the thermal conductivity of the gypsum specimens with the addition of polymer and aerogel were respectively over 23% and 6% lower than the non-modified gypsum specimen.