Abstract
The lamellar microstructure of plasma-sprayed ZrO2-8wt.%Y2O3 (8YSZ) coatings was quantitatively characterized by a novel approach. The porous structure of the coating was visualized through infiltrating the tracer into voids in the coating combining with the energy dispersed X-ray line analysis of the tracer in the coating. The quantitative characterization parameters included the mean lamellar interface bonding ratio, mean lamellar thickness and width distribution of lamellar interface gaps. 8YSZ coatings were deposited by plasma spraying under different spray distances to reveal the effect of spray distance on the lamellar microstructure of plasma-sprayed 8YSZ coatings. The results showed that the maximum mean bonding ratio was 32% when the coating was deposited at spray distance from 65 to 80 mm. As spray distance was increased to 100-120 mm, the mean bonding ratio was reduced. The mean lamellar thickness was not significantly influenced by spray distance although it was found that the mean lamellar thickness tended to increase with the increase of spray distance from 80 mm. It was observed that lamellar interface gaps in the coating were mainly in submicrometer order. With the increase of spray distance, the mean width of interface gaps and fraction of wide interface gaps tended to increase.
