Treatment of turbine blades in electric power stations by adding nano oxides to the matrix material (Al80-Ni20)

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Abstract A base material of Al80-Ni20 was used and mixed with variable proportions of Nano chromium oxide (Cr2O3) at percentages of 2, 4, 6, 8 and 10%, as well as with Nano magnesium oxide (MgO) at percentages of 2, 4, 6, 8 and 10%. These mixtures were then applied using the thermal spraying method with a flame. This particular method is commonly used for repairing cracks and protecting turbine blades in electric power stations from external corrosion. However, it is important to note that this method may face challenges when exposed to high-temperature water vapour, salts and other working conditions experienced by turbine blades. Samples were prepared by thermally sintering the coating at 1000 °C for two hours. Various measurements were performed to assess the structural properties using a scanning electron microscope (SEM), as well as other physical tests such as porosity, hardness, adhesion strength and frictional wear. The SEM analysis revealed that the presence of 10% Cr2O3 resulted in a surface that was uniformly free from external defects, whereas the addition of MgO led to a less homogeneous surface. The physical data obtained indicated a preference for Cr2O3, as evidenced by the porosity results (4.5%) observed after thermal sintering at 10%, as well as the hardness (193 HV), adhesion strength (40 MPa) and wear (2.90 × 10−5 g cm−1) measurements. Moreover, the analyses of the properties of MgO under the same conditions included porosity (10%), hardness (155 HV), adhesion strength (35 MPa) and wear (5.50 × 10−5 g cm−1).