Enhanced capacitance performance of Al2O3–TiO2 composite thin film via sol–gel using double chelators

Characterization of Ceramics Coatings Processed by Sol-Gel for Cutting Tools

In order to obtain better cutting tool performance, the coatings appear as an alternative in the machining process. The goal of the coating is to improve tribological conditions in the chip-tool and tool-workpiece interfaces. On the other hand, the use of coated tools decreases the wear of the tools. This study discusses the ceramic coatings characterization deposited in WC tools. The Al2O3 and TiO2 films present properties such as thermal stability, chemical inertia, high hardness, and good mechanical properties. These coatings were prepared by sol-gel technology. The results indicated that the multilayer coating presents better adhesion on the substrate. Moreover, lower coefficients of friction were found for the coated tools. The analysis of variance (ANOVA) was used to evaluate the influence of the cutting parameters and tool coating on the cutting force. The lower cutting force was obtained using the multilayer-coated tool. Thus, the sol-gel method appears as a novel technique to deposit coating in the WC tools to improve their performance.

TiO₂-ZnO Binary Oxide Systems: Comprehensive Characterization and Tests of Photocatalytic Activity

A series of TiO₂-ZnO binary oxide systems with various molar ratios of TiO₂ and ZnO were prepared using a sol-gel method. The influence of the molar ratio and temperature of calcination on the particle sizes, morphology, crystalline structure, surface composition, porous structure parameters, and thermal stability of the final hybrids was investigated. Additionally, to confirm the presence of characteristic surface groups of the material, Fourier transform infrared spectroscopy was applied. It was found that the crystalline structure, porous structure parameters, and thermal stability were determined by the molar ratio of TiO₂ to ZnO and the calcination process for the most part. A key element of the study was an evaluation of the photocatalytic activity of the TiO₂-ZnO hybrids with respect to the decomposition of C.I. Basic Blue 9, C.I. Basic Red 1, and C.I. Basic Violet 10 dyes. It was found that the TiO₂-ZnO material obtained with a molar ratio of TiO₂:ZnO = 9:1 and calcined at 600 °C demonstrates high photocatalytic activity in the degradation of the three organic dyes when compared with pristine TiO₂. Moreover, an attempt was made to describe equilibrium aspects by applying the Langmuir-Hinsherlwood equation.