Liquid Feedstock Plasma Spraying: An Emerging Process for Advanced Thermal Barrier Coatings

Markocsan, Nicolaie; Gupta, Mohit; Joshi, Shrikant V.; Nylén, Per; Li, Xinhai; Wigren, J.

doi:10.1007/s11666-017-0555-4

Cited by 34 publications

(7 citation statements)

References 54 publications

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“…The suspension plasma spray (SPS) process is considered as a technique that enables variations of thermally sprayed coatings e.g., from highly dense and vertically cracked (DVC) to porous, feathery, and columnar microstructures [1]. There is a growing demand for yttria-stabilized zirconia (YSZ) suspensions to deposit thermal barrier coatings (TBC), either to generate the main TBC ceramic layer or as a repair method [2].…”

Section: Introductionmentioning

confidence: 99%

“…There is a growing demand for yttria-stabilized zirconia (YSZ) suspensions to deposit thermal barrier coatings (TBC), either to generate the main TBC ceramic layer or as a repair method [2]. In both cases, the preferred microstructure contains large globular pores and connected cracks that can potentially yield high strain tolerance and low thermal conductivity [1,3].…”

Section: Introductionmentioning

confidence: 99%

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A Comparative Study of YSZ Suspensions and Coatings

et al. 2019

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The demand for suspensions that are used in thermal spray processes is expanding from research labs using the lab-prepared suspensions toward actual coating production in different industrial sectors. Industrial applications dictate the reduced production time and effort, which may in turn justify the development of the market for ready-to-use commercial suspensions. To this end, some of the powder suppliers have already taken steps forward by introducing, to the market, suspensions of some of the most used materials, such as yttria-stabilized zirconia (YSZ), alumina, and titania. However, there is a need to compare the suspension characteristics over time and the resultant coatings when using these suspensions when compared with the freshly prepared homemade suspensions. In this work, such a comparison is done using YSZ suspensions of the sub-micron to a few micron powders. In addition, some changes in the suspensions’ formula were performed as a tool to vary the coatings’ microstructures in a more predictable way, without any variation of the spray parameters. The coatings were generated while using both radial and axial injection of the suspensions into Oerlikon-Metco 3MB and Mettech Axial III plasma spray torches, respectively. A clear effect of suspension viscosity on the coating microstructure was observed using the 3MB torch with a radial injection of suspension (i.e., cross flow atomization). However, the viscosity role was not dominant when using the Axial III torch with an axial feed injection system (i.e., coaxial flow atomization).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Comparative Study of YSZ Suspensions and Coatings

et al. 2019

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“…An overwhelming proportion of SPS studies reported so far have been exclusively driven by interest in TBCs. This is attributable to the use of nano or sub-micron sized feedstock enabling realization of a unique columnar microstructure similar to the electron beam physical vapor deposition (EB-PVD) processed TBCs [50]. It may also be mentioned that the deposition rates achievable by SPS are significantly faster than in the case of EB-PVD and the former is, therefore, also deemed more economical [51].…”

Section: Sps Coatings For Tbc Applicationsmentioning

confidence: 99%

Advanced Coatings by Thermal Spray Processes

Joshi

Nylén

2019

Technologies

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Coatings are pivotal in combating problems of premature component degradation in aggressive industrial environments and constitute a strategic area for continued development. Thermal spray (TS) coatings offer distinct advantages by combining versatility, cost-effectiveness, and the ability to coat complex geometries without constraints of other in-chamber processes. Consequently, TS techniques like high-velocity oxy-fuel (HVOF) and atmospheric plasma spray (APS) are industrially well-accepted. However, they have reached limits of their capabilities while expectations from coatings progressively increase in pursuit of enhanced efficiency and productivity. Two emerging TS variants, namely high-velocity air-fuel (HVAF) and liquid feedstock thermal spraying, offer attractive pathways to realize high-performance surfaces superior to those hitherto achievable. Supersonic HVAF spraying provides highly adherent coatings with negligible porosity and its low processing temperature also ensures insignificant thermal ‘damage’ (oxidation, decarburization, etc.) to the starting material. On the other hand, liquid feedstock derived TS coatings, deposited using suspensions of fine particles (100 nm–5 µm) or solution precursors, permits the production of coatings with novel microstructures and diverse application-specific architectures. The possibility of hybrid processing, combining liquid and powder feedstock, provides further opportunities to fine tune the properties of functional surfaces. These new approaches are discussed along with some illustrative examples.

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“…Suspension plasma spray (SPS) process is considered as a technique that enables variations of thermally sprayed coatings e.g., from highly dense and vertically cracked (DVC) to porous, feathery and columnar microstructures [1]. There is a growing demand for yttria-stabilized zirconia (YSZ) suspensions to deposit thermal barrier coatings (TBC), either to generate the main TBC ceramic layer or as a repair method [2].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of YSZ Suspensions and Coatings

Tarasi¹,

Alebrahim²,

Dolatabadi³

et al. 2019

Preprint

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The demand for suspensions used in thermal spray processes is expanding from research labs using the lab-prepared suspensions toward actual coating production in different industrial sectors. Industrial applications dictate reduced production time and effort which may in turn justify the development of the market for ready-to-use commercial suspensions. To this end, some of the powder suppliers have already taken steps forward by introducing to the market suspensions of some of the most used materials such as yttria-stabilized zirconia (YSZ), alumina and titania. There is, however, a need to compare the suspension characteristics over time and the resultant coatings when using these suspensions as compared with the freshly prepared home-made suspensions. In this work, such comparison is done using YSZ suspensions of the sub-micron to a few micron powders. In addition, some changes in the suspensions' formula were performed as a tool to vary the coatings’ microstructures in a more predictable way, without variation of spray parameters. The coatings were generated using both radial and axial injection of the suspensions into Oerlikon-Metco 3MB and Mettech Axial III plasma spray torches, respectively. A clear effect of suspension viscosity on the coating microstructure was observed using the 3MB torch with radial injection of suspension (i.e. cross flow atomization). The viscosity role, however, was not dominant when using the Axial III torch with axial feed injection system (i.e. coaxial flow atomization).

show abstract

Liquid Feedstock Plasma Spraying: An Emerging Process for Advanced Thermal Barrier Coatings

Cited by 34 publications

References 54 publications

A Comparative Study of YSZ Suspensions and Coatings

A Comparative Study of YSZ Suspensions and Coatings

Advanced Coatings by Thermal Spray Processes

A Comparative Study of YSZ Suspensions and Coatings

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