Effect of in-flight particle behavior on the morphology of flame sprayed Er2O3 splats

The morphology and microstructure of splats impact the comprehensive capability of a new coating methodology called chelate flame spraying (CFS). This study addresses the quantitative characterization of the spread morphologies of flame sprayed Er2O3 splats directly deposited under different spray conditions on aluminum alloy substrates with a mirror finish. The influence of the in-flight particle temperature and velocity, carrier gas type, and carrier gas ratio on the solidification mechanism of molten droplets was investigated. Image analysis methods were employed to identify single splats from the morphology observed with field-emission scanning electron microscopy (FE-SEM). In addition, Er2O3 films were synthesized on an Al-Mg alloy (A5052) substrate using N-2 or O-2 as the carrier gas. When O-2 was used as the carrier gas, 109-mu m-thick films were deposited on the A5052 substrate. The cross-sectional porosity of the films was 3.8%. In contrast, films with 101-mu m thickness were synthesized on the A5052 substrate when N-2 was used as the carrier gas. The cross-sectional porosity of these films was 13.8%. The results showed that the carrier gas type (N-2) and carrier gas ratio had a significant effect on the flattening behavior of the molten droplets. A spraying method combined with multidimensional modes is proposed to control the morphology of the splats.

Automated summary

This study investigates the influence of carrier gas type and ratio on the solidification mechanism of flame sprayed Er2O3 splats deposited on aluminum alloy substrates, and proposes a spraying method combined with multidimensional modes to control splat morphology. The results show that carrier gas type (N-2) and ratio significantly affect the flattening behavior of molten droplets, providing insights into optimizing coating methodologies.