Development and Application of Binary Suspensions in the Ternary System Cr2O3-TiO2-Al2O3 for S-HVOF Spraying

Potthoff, Annegret; Kratzsch, Robert; Barbosa, Maria; Kulissa, Nick; Kunze, O. A.; Toma, Filofteia-Laura

doi:10.1007/s11666-018-0709-z

Cited by 16 publications

(13 citation statements)

References 13 publications

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“…Among different technologies, the most intensively studied are suspension plasma spraying (SPS) and suspension high-velocity oxygen fuel spraying (S-HVOF) [1,2], patented, respectively, by Gitzhofer et al in 1997 [3] and Gadow et al in 2011 [4]. Since that time, these techniques have been developed in parallel [5,6]. By spraying with feedstocks of submicrometer-or even nanometer-sized powders, the microstructural features of coatings change significantly and, thus, the different functional properties of coatings may be improved [7,8].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Microstructural Characterization and Phase Compositions of Thermally Sprayed Al2O3-TiO2 Coatings Obtained from Powders and Water-Based Suspensions

et al. 2020

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In this work, the alumina (Al2O3) and alumina-titania coatings with different contents of TiO2, i.e., Al2O3 + 13 wt.% TiO2 and Al2O3 + 40 wt.% TiO2, were studied. The coatings were produced by means of powder and liquid feedstock thermal spray processes, namely atmospheric plasma spraying (APS), suspension plasma spraying (SPS) and suspension high-velocity oxygen fuel spraying (S-HVOF). The aim of the study was to investigate the influence of spray feedstocks characteristics and spray processes on the coating morphology, microstructure and phase composition. The results revealed that the microstructural features were clearly related both to the spray processes and chemical composition of feedstocks. In terms of phase composition, in Al2O3 (AT0) and Al2O3 + 13 wt.% TiO2 (AT13) coatings, the decrease in α-Al2O3, which partially transformed into γ-Al2O3, was the dominant change. The increased content of TiO2 to 40 wt.% (AT40) involved also an increase in phases related to the binary system Al2O3-TiO2 (Al2TiO5 and Al2−xTi1+xO5). The obtained results confirmed that desired α-Al2O3 or α-Al2O3, together with rutile-TiO2 phases, may be preserved more easily in alumina-titania coatings sprayed by liquid feedstocks.

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Section: Introductionmentioning

confidence: 99%

A Study on the Microstructural Characterization and Phase Compositions of Thermally Sprayed Al2O3-TiO2 Coatings Obtained from Powders and Water-Based Suspensions

et al. 2020

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“…Coating thicknesses, morphologies and properties can be varied over an extremely wide range, as presented i.e. [15][16][17]. Direct processing of nano-and sub-micon-sized powders is possible with suspensions, but more important is the advantage of directly using the finely dispersed ceramic oxide powders of widely varying grain size, purity, etc.…”

Section: Introductionmentioning

confidence: 99%

Investigation of CMAS Resistance of Sacrificial Suspension Sprayed Alumina Topcoats on EB-PVD 7YSZ Layers

et al. 2019

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Molten calcium-magnesium-aluminum-silicate (CMAS) mineral particles cause significant degradation of thermal barrier coatings (TBCs) in aero-engines. One approach to protect the TBC coating against the CMAS attack is the application of a sacrificial coating on top of the TBC coating. In this work sacrificial Al 2 O 3 coatings were deposited on top of EB-PVD 7YSZ layers using suspension thermal spraying starting from an aqueous Al 2 O 3 suspension. Spray parameters were varied in order to produce sacrificial topcoats with two different microstructures and porosities levels. The coating systems were tested under CMAS attack by performing shortand long-time infiltration tests at 1250 °C. It was found out that the porosity and morphology of Al 2 O 3 coatings strongly influenced the CMAS infiltration kinetics and the formation of various phases. CMAS mitigation depended on the interaction between the coating morphology which rules the driving force for infiltration, as well as on the reaction speed between alumina and the CMAS deposit.

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“…Berger, Toma, and their group from Fraunhofer Institute in Dresden (Germany) suggested adapting the suspension properties to the final application of coating. Consequently, they proposed the multi-material suspensions [175][176][177][178]. Molina et al [179] proposed the formulation of stable, highly concentrated, and low viscosity liquid feedstock with the use of bimodal or multimodal solid size distribution.…”

Section: Feedstock Used In Thermal Spray Processesmentioning

confidence: 99%

Review of Functionally Graded Thermal Sprayed Coatings

et al. 2020

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The paper briefly describes major thermal spray techniques used to spray functionally graded coatings such as atmospheric plasma spraying, high velocity oxy-fuel spraying, suspension and solution precursor plasma spraying, and finally low and high pressure cold gas spray method. The examples of combined spray processes as well as some examples of post spray treatment including laser and high temperature treatments or mechanical one, are described. Then, the solid and liquid feedstocks used to spray and their properties are shortly discussed. The reviewed properties of functional coatings include: (i) mechanical (adhesion, toughness, hardness); (ii) physical (porosity, thermal conductivity and diffusivity, thermal expansion, photo-catalytic activity), and; (iii) bioactivity and simulated body fluid (SBF) corrosion. These properties are useful in present applications of functionally graded coatings as thermal barriers, the bioactive coatings in prostheses, photo-catalytic coatings in water treatment, coatings used in printing industry (anilox and corona rolls). Finally, some of the future possible fields of functional thermal sprayed coatings applications are discussed, e.g., to coat polymer substrates or to use the cheap technology of low pressure cold gas spray method instead of expensive technology of vacuum plasma spraying to obtain bond coatings.

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Development and Application of Binary Suspensions in the Ternary System Cr2O3-TiO2-Al2O3 for S-HVOF Spraying

Cited by 16 publications

References 13 publications

A Study on the Microstructural Characterization and Phase Compositions of Thermally Sprayed Al2O3-TiO2 Coatings Obtained from Powders and Water-Based Suspensions

A Study on the Microstructural Characterization and Phase Compositions of Thermally Sprayed Al2O3-TiO2 Coatings Obtained from Powders and Water-Based Suspensions

Investigation of CMAS Resistance of Sacrificial Suspension Sprayed Alumina Topcoats on EB-PVD 7YSZ Layers

Review of Functionally Graded Thermal Sprayed Coatings

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