Investigations were undertaken to determine the erosion-corrosion resistance of plasma-sprayed titanium dioxide (TiO2) nanostructured coatings. Nanopowders were used to make agglomerates. Both conventional TiO2-coated and nanostructured samples (n-TiO2) were exposed to 3.5 wt% sodium chloride (NaCl) containing 2 vol% polystyrene particles at velocities ranging from 1 ms−1 to 4 ms−1. In general they exhibited a fairly good resistance to erosion-corrosion. The nanostructured samples processed, sprayed, and densified (AE 9342) before plasma spraying showed relatively higher resistance to erosion-corrosion compared to sample AE 9303, which was spray-dried and chemically precipitated before spray. It is shown by morphological studies that a homogeneous distribution of nanoagglomerates and dense packing of splats with larger melted zones creates conditions favorable to resist erosion-corrosion. The splat boundaries appear to offer a preferential passage to erosion-corrosion.

Subject
Water, Coatings, Erosion resistance, Corrosion rate, Chemical resistance, Surface morphology, Surfaces, Titanium oxide, Sodium chloride solution, Powders, Titanium, Corrosion resistance, Erosion corrosion
Keywords:
erosion-corrosion, homogeneous structure, nanofeed powder, nanostructured coatings, plasma air spraying, splat lamellae, spraying key parameters, surface topography
NACE International
2009
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