A SrTiO3 electroceramic with perovskite structure was produced by the calcination of a mixture of SrCO3 and TiO2 intensively grounded by high energy milling. For this purpose, raw materials were mixed in stoichiometric amounts in a planetary type mill; the obtained powder mixture was calcined for 2 h at temperatures between 800 and 1300°C. Samples resulting from the calcination were characterized by XRD, FTIR, SEM analysis and electrical measurements. From XRD, it was determined that the SrTiO3 formed presents the cubic structure of perovskite. The complete reaction for SrTiO3 compound formation occurs at 1200°C. Micrograph observations indicate the presence of a homogeneous microstructure with tiny grain size. The measured values of electrical resistivity were within the typical range of insulating materials.

Currently, the disposal of waste tires is considered one of the priority environmental and public health problems worldwide. Every year, more than 1.4 billion unused tires are placed in landfills. Population growth, economic development, and a strong demand for vehicle production in the automotive industry increase this problem. In Mexico, nearly 36 million unused tires are deposited in landfills or clandestine deposits, the vast majority being burned or accumulated in the open air. The lack of regulations in the handling, disposal, and recycling of tires creates a worrying panorama for environmental care and the problems that this entails. The objective of this work is to propose a viable alternative for the final disposal and recycling of waste tires through the implementation of a company for the manufacture of products based on recycled rubber in the state of Tamaulipas, Mexico, reducing environmental pollution by these wastes and generating sources of employment through a sustainable company. For this purpose, a study was carried out in Tamaulipas, Mexico, through surveys to determine the number of tires that can be obtained and determine the feasibility of the business; subsequently, a prediction was made using simulation software to design and estimate the expected production in the manufacture of parking bumpers using two scenarios with two and four workers. Likewise, specialized software was used to optimize waste tire collection routes from the different tire stores to the company’s location. The results show that with an optimal design of the tire collection routes, up to 483 tons of waste tires can be recovered per year, representing 10% of the total unused tires in Tamaulipas. Because it is an environmental and social problem, installing a company manufacturing products based on recycled rubber is feasible and has a high probability of success for the region studied. According to the simulation, employing four workers increases productivity and decreases manufacturing costs. Through the simulation, three tire collection routes were determined considering the total number of tire stores in the city where the company is located.

High entropy alloys (HEAs) of the type CrCuFeNiTi-Alx were processed through mechanical alloying. The aluminum concentration was varied in the alloy, to determine its effect on the HEAs’ microstructure, phase formation, and chemical behavior. X-ray diffraction studies performed on the pressureless sintered samples revealed the presence of structures composed of face centered cubic (FCC) and body centered cubic (BCC) solid-solution phases. Since the valences of the elements that form the alloy are different, a nearly stoichiometric compound was obtained, increasing the final entropy of the alloy. The aluminum was partly responsible for this situation, which also favored transforming part of the FCC phase into BCC phase on the sintered bodies. X-ray diffraction also indicated the formation of different compounds with the alloy’s metals. Bulk samples exhibited microstructures with different phases. The presence of these phases and the results of the chemical analyses revealed the formation of alloying elements that, in turn, formed a solid solution and, consequently, had a high entropy. From the corrosion tests, it could be concluded that the samples with a lower aluminum content were the most resistant to corrosion.

Aluminum matrix composites have recently taken an important role in advanced applications because they have a good combination of physical and chemical properties. For this reason, in this work, aluminum composites, with additions of ceramic particles (mullite or tungsten carbide), were manufactured in order to determine the effect of those particles on the mechanical properties and microstructure of aluminum. The manufacture of the composites was carried out by means of powder metallurgy. We studied composites with additions of 0.5 and 1 vol.% of the respective ceramic. Composites were sintered at 580 and 601 °C, which corresponds to 88 and 91% of the melting point of aluminum, respectively. Observations in SEM, together with EDX analysis, confirm that mullite particles are located at intragranular and transgranular positions of the aluminum matrix, while tungsten carbide particles were found mostly at intragranular areas of the matrix. From the analysis of the studied ceramics, it was found that with the use of mullite, there are greater improvements in the hardness and elastic modulus of the manufactured composite.

Samples of Sr₄Al₆O₁₂SO₄ are obtained through a solid-state reaction of Al₂O₃, SrSO₄, and SrCO₃. The samples are then made into 1 and 4 cm pellets by compacting them at 100MPa and sintering them at 1400 °C for 4 h. The compound is analyzed using X-ray diffraction. Static immersion and wettability tests are carried out to evaluate corrosion resistance in contact with Al–Si. Corrosion tests are conducted by immersing the samples at 800, 900, and 1000 °C for 24, 50, and 100 h, while wettability is studied at 900, 1000, and 1100 °C for 2 h. Afterwards, the samples are subject to metallographic preparation. The samples are then analyzed using optical microscopy, scanning electron microscopy, and image analysis. In general, reaction products consisting of alumina, spinel, oxides, and sulfates are found. The contact angles obtained are between 124° and 135°. It is concluded that the Sr₄Al₆O₁₂SO₄ ceramic substrate is resistant to corrosion by the Al–Si alloy because of the slight thickness of the reaction products found in the samples (73 μm), considering the severe conditions of the experiment: 1000 °C and 100 h of isothermal temperature. Furthermore, Sr₄Al₆O₁₂SO₄ is not wettable by Al–Si alloys. These results suggest that the ceramic substrate could be used in the refractory industry, possibly as an additive to commercial refractory ceramics. For future work, it is recommended to carry out the same study with the aluminum–magnesium alloy and as an additive in commercial refractory ceramics.