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Mixtures of Ni-based filler metal without and with 0.5, 1, and 2% WC nanoparticles (NPs) were methodologically tested in order to improve the wear behaviour of WC/Ni-based overlays deposited on low carbon steel by the plasma transferred arc (PTA) process. On adding 2% WC NPs, the longitudinal direction overlay microstructure was modified to have a fibrous appearance. The mechanism to improve WC particle distribution and thus prevent microcrack propagation in the overlays implies a liquid-phase viscosity change. Results of pin-on-disk tests in the overlay using filler metal with 2% WC NPs show that the combined effect of fibrous microstructure and W-rich phases in the overlay, decreases the volume loss by 76% and 78% in comparison with overlays without WC NPs for a 1 and 5 N load, respectively. These outcomes might be of interest for the mining industry, where machinery and equipment are exposed to extreme wear conditions.

Metalloporphyrins (MP) and metallophtalocyanines (MPc) are innovative materials with catalytic properties that have attracted attention for their application for diverse electrochemical purposes. The presence of metallic centers in their structure offers a redox-active behavior that is being applied in the design of solid electrodes for the quantification of biomolecules, water contaminants, and pharmaceuticals, among others. Herein, we collect the recent information about porphyrin and phthalocyanine complexes as modifiers of electrodes, and the important aspects of the design, characterization, and application of these electrodes.

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The benzene pollutant in gaseous phase was successfully degraded by using ZnO + Zn2TiO4 multicomponent oxide thin films as photocatalysts. The films were obtained with different Ti/Zn ratios (0, 0.20, 0.40, 0.45, 0.50, 0.67, 0.84, and 1) by the sol-gel route. The initial level of benzene concentration was 110 ± 10 ppm. The process was carried out under different conditions of relative humidity (RH): 25, 50, and 80 % in a batch-type reactor, at room temperature. The results show benzene degradation near to 95 % at t = 240 min, where the multicomponent oxide semiconductor has a Ti/Zn ratio of 0.67. Meanwhile, with the TiO2 thin films, only a degradation of 70 % was reached at the same measurement conditions. This synergistic effect on the photocatalytic activity is a result of the coupling of both semiconductor oxides. An adverse effect on the photocatalytic activity was observed as the relative humidity increases.