In situ Particle Generation and Splat Formation During Solution Precursor Plasma Spraying of Yttria‐Stabilized Zirconia Coatings

Abstract

Thermal barrier coatings (TBCs) based on Yttria-stabilized Zirconia (YSZ) deposited by the solution precursor plasma spray (SPPS) technique have been claimed to exhibit superior durability compared to conventional plasma spraying and even electron-beam physical vapor deposition. This has been attributed to the interesting features, like vertical cracks, nanosized pores, and fine splats that are inherent to SPPS-deposited YSZ coatings. However, the mechanism of coating formation during SPPS processing is not yet well understood. This study is aimed at understanding the influence of some key SPPS process variables on in situ generated particles and subsequent splat formation to augment the current level of understanding. The plasma power employed was found to play a major role in governing the morphology and phase constitution of in situ generated particles. The shape and size of the YSZ splats were also significantly influenced by the plasma power, but the substrate pre-heat was also noted to be a major determining factor. It was further observed that the SPPS typically involved in situ generation of very fine particulates (50-500 nm) and splats (typically 200-2000 nm), which lead to its nano-porous and homogeneous microstructure. The YSZ coating characteristics were also found to correlate well with the above results.K. Faber-contributing editor Manuscript No. 29529.

Dynamic interactions of ingested molten silicate particles with air plasma sprayed thermal barrier coatings

“…For this study, the two most frequently used microstructures of 7YSZ TBCs in the gas turbine industry were evaluated: porous Both microstructures have seen use in combustor liners, while YSZ DVC specifically is an economically attractive microstructural alternative to some of the other coating technologies such as columnar suspension plasma sprayed TBCs [44,45,46,47].…”

Review of Functionally Graded Thermal Sprayed Coatings

“…Subsequently, many coatings for different applications were sprayed by SPPS. The examples are: thermal barrier coatings (TBC) [54,55], coatings solid oxy-fuel cells [56,57], biomaterial coatings [58,59], photocatalytic coatings [60,61], coatings for gas sensors [62,63], environmental barrier coatings [64], and many others.…”

Micro-nano structured functional coatings deposited by liquid plasma spraying

“…During spraying, the solution is injected into the plasma jet directly or after atomization. After a series of physical and chemical processes such as solvent evaporation, nucleation growth, heating decomposition, and particle melting, a coating will be deposited on the substrate surface [35]. Although the processes were proposed in the middle of the 1990s, SPS and SPPS are new plasma spray methods based on liquid raw materials, which can deposit ultrafine particles to obtain coatings with fine microstructures and excellent functional properties [36].…”