Reinforced concrete is one of the most used materials in the construction industry, in which the quality specifications necessary for its acceptance must be met. In the present work, the main focus is on studying the correlation that exists between the tests of resistance to compression and bending with the electrochemical test of corrosion potentials, electrical resistivity and ultrasonic pulse velocity. Specimens of hydraulic concrete with a water/ cement ratio, (w/c) = 0.50, were made according to the ACI 211.1 design method, which is based on the physical characteristics of the aggregates and is the most used in the premix plants. The study was carried out during the hydraulic concrete curing stage in which very favorable results were obtained in the correlation that exists between conventional tests and non-destructive and electrochemical tests.
The present investigation was conducted to study the oxidation kinetics of nickel-based superalloy 263, used in the manufacture of rings for aircraft engines. For carrying out this study, we first conducted microstructural characterization of the pieces using the techniques of optical microscopy, scanning electronic microscopy, and X-ray diffraction. Subsequently, using the thermogravimetric analysis, the kinetic oxidation of the metal was performed in a temperature range between 700 and 1000°C, using atmospheres of O 2. The results of the micrographs show the formation of a protective oxide film on the surface of the material in different oxidizing agents. Finally, it was found that the kinetics of high-temperature oxidation of the superalloy C-263 obeys the parabolic rate law.
Titanium is for aerospace production is of 80%. In an aircraft structure, 15% of the weight is titanium. The principal reasons to use titanium alloys are the save of weight, increase performance temperatures ratio and corrosion resistance. To analysed corrosion behavior of Ti alloys, polarization potentiodynamic cyclic was employed. Electrolytes used were H2SO4 and NaCl at 3.5% wt. The type of corrosion presented in Ti alloys was generalized in both electrolytes.
Aluminium alloys are used on aerospace and automotive industry due to excellences mechanical properties. Unfortunately, aluminium alloys are susceptible to corrosion and that limit them in some corrosive environments. The aim of this work is researching the characteristics of anodized film generated with sulfuric-citric acid through to electrochemical techniques. For matrix material, an Aluminium (Al) 2024 alloy was used applying a mixt of sulfuric and citric acid with a current of 0.01 and 1 A at 25°C each one while 30 minutes. Electrochemical evaluation used was cyclic potentiodynamic polarization curves (CPPC) and Electrochemical Impedance Spectroscopy (EIS) in NaCl at 3.5% wt. Scanning Electron Microscopy (SEM) was used to determinate morphology and thickness of coating. Results shows that aluminium anodized with mixt of sulfuric-citric acid presented less pitting corrosion resistance with out present a significative difference in surface morphology.
Nowadays aeronautic industry is looking for lighter materials as Ti alloys because they resist higher stress than aluminium alloys and are lighter than steel alloys, saving of this way volume and weight. The EN technique was used to evaluate the corrosión behaviour of different Ti-alloys in H2SO4 and NaCl at 3.5 wt% solutions. All samples presented mix corrosion being an indicative of the instability of passive layer generated in the electrolytes.
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