In situ particle generation and splat formation during solution precursor plasma spraying of yttria-stabilized zirconia coatings

• 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. © 2011 The American Ceramic Society.

Nyckelord

Coating characteristics

Coating formation

Current levels

Electron beam-physical vapor deposition

Fine particulates

Homogeneous microstructure

In-situ

Nano-porous

Nanosized pores

Particle generation

Phase constitution

Plasma power

Process Variables

Shape and size

Solution precursor

Solution precursor plasma spray

Splat formation

Vertical crack

Zirconia coatings

Coatings

Physical vapor deposition

Pinch effect

Plasma deposition

Plasma jets

Plasma spraying

Plasmas

Surface plasmon resonance

Thermal spraying

Yttria stabilized zirconia

Yttrium alloys

Zirconia

Thermal barrier coatings

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