The initial stages of corrosion of AZ31B magnesium alloy, immersed in Ringer′s solution at 37 °C body temperature for four days, have been evaluated by independent gravimetric and chemical methods and through electrochemical impedance spectroscopy (EIS) measurements. The corrosion current densities estimated by hydrogen evolution are in good agreement with the time-integrated reciprocal charge transfer resistance values estimated by EIS. The change in the inductive behavior has been correlated with difference in the chemical composition of corrosion layers. At the shorter immersion of 2 days, EDS analysis of cross section of the uniform corrosion layer detected Cl and Al elements, perhaps as formed aluminum oxychlorides salts.

In materials science, the knowledge of the thermal properties of thin films on thick substrates is crucial in determining the role of the film in the physical properties of the entire system. Even though the role of the film can be very important, the determination of its thermal properties is a challenging task due to the fact that its contribution to heat transfer is generally hard to single out from the influence of the substrate. Herein, a simple analytical methodology, based on the photoacoustic technique, useful in the thermal characterization of thin films on thick substrates, is presented. The approach is based on illuminating one side of the substrate with a modulated laser beam and monitoring the thermal contrast when a thin film is formed on the opposite side. This methodology allows to unambiguously determine the volumetric heat capacity of micrometric polymeric thin films. The limits of applicability of the method as well as the possibility of performing a full characterization of the thermal properties of the film are discussed.

Mixed-halide organic–inorganic hybrid perovskites are considered promising light-absorbing materials in the development of solar cells related to the obtained high-power conversion efficiency. Current efforts are focused on the study of the energy-conversion mechanisms, where the nonradiative recombination pathway is the least explored. In this work, a combination of optical and photoacoustic spectroscopies is used to determine the visible spectral light-into-heat conversion efficiency of lead-based mixed-halide organic–inorganic hybrid perovskites in a semicomplete n-i-p mesoscopic perovskite solar cell (PSC). A remarkable average conversion efficiency of about 87% has been found for the nonradiative combination in the perovskite, with the estimated composition F A 0.71 M A 0.29 P b I 2.9 B r 0.1 in the wavelength range of 400 to 800 nm. As a result, 13% of the incident light is transformed in radiative recombination processes and/or photodegradation of the material. Furthermore, the extinction coefficient and refractive index of the material are reported, and it was found that the optical constants and the optical absorption in the short-wavelength range are significantly smaller than previously reported for M A P b I 3 .