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The study describes the successful development of a TiO2 ceramic substrate with a protective nano-Al2O3 coating using two different coating techniques: microwave combustion and polymeric methods. The coated ceramics demonstrate enhanced corrosion resistance compared to the uncoated substrate. The optimal TiO2 substrate was prepared by firing it at 1000 °C. This was done to give the desired physical properties of the TiO2 substrate for the coating procedures. Nano-Al2O3 powder was coated onto the surface of the TiO2 substrates. The TiO2 substrates with the Al2O3 coating were then calcined (heat-treated) at 800 and 1000 °C. The structures, morphology, phase composition, apparent porosity, bulk density, and compressive strength of the substrate and coated substrate were characterized. Upon firing at 1000 °C, it was discovered that the two phases of TiO2—rutile and anatase—combine in the substrate. Once the substrate has been coated with nano Al2O3 at 1000 °C, the anatase is transferred into rutile. When compared to the substrate, the coated substrate resulted in a decrease in porosity and an increase in strength. The efficiency of the ceramic metal nanoparticles Al2O3 as a good coating material to protect the TiO2 substrates against the effect of the corrosive medium 0.5 M solution of H2SO4 was measured by two methods: potentio-dynamic polarization (PDP) and the electrochemical impedance spectroscopy (EIS). The results indicated that the corrosion rate was decreased after the substrate coated with alumina from (67.71 to 16.30 C.R. mm/year) and the percentage of the inhibition efficiency recorded a high value reaching (78.56%). The surface morphology and composition after electrochemical measurements are investigated using SEM and EDX analysis. After conducting the corrosion tests and all the characterization, the results indicated that the coated TiO2 substrate prepared by the polymeric method at 800 °C displayed the best physical, mechanical, and corrosion-resistant behavior. [ABSTRACT FROM AUTHOR]

The aim of this work is to synthesize the seeds of CoxMg1-xAl2O4 nano-spinel particles for pigment fabrication using a microwave-assisted method. Also, we report on a novel, less toxic, flexible, and reproducible microwave- assisted method for starch-based synthesis of spinels. Furthermore, substantial efforts were devoted to obtaining a nanopowder while reducing total synthesis time from many hours to a few minutes. The obtained powders were characterized by XRD, FT-1R, TEM, and EDSA techniques. The results show that CoxMg1-xAl2O4 spinel is in an amorphous form after microwave treatment at 1000 W with particle sizes of less than 20 nm and that spinel first began to crystallize at a temperature of 550 °C. [ABSTRACT FROM AUTHOR]

Ceramic materials account for the largest percentage of waste generated in the construction and demolition of concrete structures. Currently, this ceramic waste is disposed of in landfills, due to the lack of alternative disposal options and the lack of awareness of options for the reuse of these materials. This study aims to identify the existing alternatives and establish the potential for the reuse and valorization of ceramic waste. This analysis of alternatives for the reuse and valorization of ceramic waste is carried out through a bibliographic review focused on identifying the existing options for the reuse and valorization of ceramic waste. For each existing alternative, a brief description of the methodology used is made and the main results achieved in each study are highlighted. Based on the bibliographic review, some alternatives for the reuse of ceramic materials are presented. It was established that ceramic waste is currently used mainly in the formulation of concrete, manufacture of electrical insulators, extraction of alumina, and as a geological barrier to contain nuclear waste. In addition, based on the properties of ceramic materials, it was concluded that the potential applications for reuse include obtaining thermal insulators, abrasive materials, coral reef regeneration, and the elaboration of structures using additive manufacturing techniques. It was found that the most economically profitable option for the reuse and valorization of ceramic waste is the manufacture of concrete, while the most viable option is the manufacture of abrasive materials. [ABSTRACT FROM AUTHOR]