Closed-cell A356 aluminum alloy foams refined and modified were successfully fabricated by using barite and calcium carbonate as thickening and foaming agents, respectively. A melt treatment consisting of adding master alloys of Al-5Ti-1B and Al-10Sr for refining the dendritic microstructure and modifying the primary eutectic silicon, respectively, were included in the foaming process. The microstructure and mechanical properties of the foams manufactured were analyzed and compared with foams produced without the refining and modifying treatments. The secondary dendritic arm spacing (SDAS) was determined by optical measurements. Lower SDAS values were obtained in foam regions closer to the mold walls due to the high solidification rate imposed during the cooling step and a decrease in the SDAS values for the foams produced with the addition of the Al-5Ti-1B master alloy was evident. Additionally, the addition of the Al-10Sr master alloy caused the formation of solid solution dendrites and a fine irregular fibrous form of silicon. Foams produced with the melt treatment exhibit a good combination of structure and mechanical properties. Therefore, the melt route established is a feasible way to improve foam performance where the lowest SDAS and the highest mechanical properties were obtained for the closed-cell foams produced.

The batteries are portable devices that allow to storage chemical energy and provide electric current directly. Inside the batteries, one of the most used materials is Lithium, which includes a large number of applications. In recent years, the investigation of ion-Na and Na-MnO₂ batteries has been intensified as an alternative to Li-MnO₂ batteries. Lithium and sodium have many similar chemical characteristics and their low cost and the wide availability of sodium are factors that can make them more used in the future. An important concern in the increase of lithium battery production lies in the limited natural resources provided by this material, and its heterogeneous distribution in the earth's crust This work is focused on the preparation of Na-MnO₂ electrodes for secondary batteries and the microstructural, structural, and electrochemical characterization of them. The synthesis technique was hydrothermal non-conventional type. The contributions are found in the comparison of the properties and electronic elements of the synthesized materials. The impact of this project is on the possible use of Na-MnO₂ electrodes as an alternative material to the one currently used in Li-MnO₂ batteries. Figure 1