SOLID PARTICLE EROSIVE WEAR BEHAVIOR OF Sol–Gel-DERIVED AA2024 THERMAL BARRIER COATINGS

Solid particle erosion behavior of non-conventional thermal barrier coatings prepared by dip coating of sol–gel 7wt.% yttria-stabilized zirconia (7YSZ) has been studied in the present paper. The purpose was to show its applicability to protect aeronautic bodies vulnerable under solid particle impact, e.g. the leading edges of the wings, the radome or the leading edges of rotor blades. The effect of operational variables on erosion rate is studied both for uncoated AA2024-T351 substrate and sol–gel-derived 7YSZ top-coat on AA2024-T351 substrate. The interactive influence of variables on erosive wear behavior is also systematically studied using an air-jet erosion tester under four different parameters such as temperature (25, 150, 275 and 400∘C), impact angle (30∘, 45∘, 60∘ and 90∘), impact particle velocity (40, 60, 80 and 100m/s) and erodent flow rate (2, 3, 4 and 5g/min) using L16 Taguchi design of experiments. The optimal experimental parameters were obtained by orthogonal arrays, signal-to-noise ratio (SNR) and analysis of variance (ANOVA) for uncoated and coated aluminum alloys AA2024-T351. The temperature was found to be the most influencing parameter followed by impact angle, impact velocity and erodent flow rate for uncoated samples. For 7YSZ sol–gel coated samples, temperature was the most influencing parameter followed by impact angle, erodent flow rate and impact velocity.