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In the present work, a study and description of the wear damage of the first-stage compressor blades of a gas turbine were conducted. The type of the equipment was a gas turbine Centaur 40 GT and the deterioration of the blades was after around 8000 h of service. This equipment is located in the City of Campeche in Mexico where the weather conditions are extremely warm. The gas turbine combines high performance operation with rugged industrial construction. This design provides high efficiency, low maintenance and a long service life. For power generation, the components that are on direct contact with air at different stages of operation are the compressor blades which are exposed to severe wear damage for the impact of particles, environmental contaminants such as salts, sands and sulphur. Due to this fact, the wear damage on the turbine blades was analysed. Firstly, a tribological characterization was conducted for obtaining the chemical composition of the turbine blades, which were in operation, by using energy dispersive X-ray analysis (EDS). Atomic Force Microscopy (AFM) was used to measure the roughness and has a perspective of the degradation of the surfaces of the blades after real service. Hardness tests were also conducted to determine the material that was employed to manufacture the blades. Additionally, optical microscopy and scanning electron microscopy (SEM) were used to identify the wear mechanisms on the surfaces. This allowed obtaining a more complete failure analysis. The wear modes were severe pitting action, large craters similar to those observed in solid particle erosion when the samples are impacted at normal incidence, corrosion and a few irregular scratches similar to ploughing action in abrasive wear. [ABSTRACT FROM AUTHOR]

In the present work, a study and description of the wear mechanisms implied in disk and shoe pads (bodies) was presented. These were subjected to real service, roughly 8 months, in a city as Poza Rica in Mexico that is extremely warm (high temperatures between 40 °C and 50 °C), which lead to cause a more rapid wear process. The surface characteristics and the differences in the wear modes of the brake pads were shown. These observations allowed concluding that high sliding and abrasion wear deformed the disk pad surfaces leading to form third body layers, friction layers and friction films that determined the friction behavior of the automotive brakes. In relation to the shoe pads, although sliding wear occurred, the wear mechanism more evident was the formation of fatigue cracks due to the impact actions with the drum (counter-body). The images of the unworn and worn surfaces were obtained by using scanning electron microscopy (SEM). In addition, energy-dispersive X-ray spectroscopy (EDS) was employed to obtain the chemical analysis of unworn and worn pads. Finally, Atomic Force Microscopy (AFM) was utilized to have a perspective of the degradation of the worn pads. [ABSTRACT FROM AUTHOR]

In this work, erosion tests were carried out to study the wear damage on a coating made of a recycled polymeric matrix (crystal polystyrene) and clay (montmorillonite (MMT)). The latter was modified and purified with bromide quaternary salts (hexadecyltrimethyl ammonium bromide). The coating preparation was by liquid via dissolving 25% crystal polystyrene in a solution of 70% ethyl acetate and 30% acetone, after this, 1 wt% of modified MMT clay was added. The clay/polystyrene matrix coating was applied by immersing wood substrates in the liquid phase of the mixture. This process was repeated five times to get the final coating layer on the substrates. An erosion rig similar to that in ASTM G76-95 was used to perform the tests. The abrasive particle used to conduct the erosion tests was glass beads with a particle size between 200 and 240 µm. The impact angles were 30°, 45°, 60° and 90° with a velocity of 2.5±0.5 m/s. The abrasive flow rate was 5.5±0.5 g/min. The room temperature was between 35 °C and 40 °C. The results showed that the coating presented its maximum erosion rate at 45°. In addition, the erosion rates were decreased in the clay–polystyrene coating compared to those observed in the uncoated specimens at all incident angles. The wear mechanisms identified in SEM images were consistent pitting action, radial cracks and deposition of particle fragments on the coating surfaces. [ABSTRACT FROM AUTHOR]