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Splat formation and microstructure of solution precursor thermal sprayed Nb-doped titanium oxide coatings

Tejero-Martin, Daniel; Pala, Zdenek; Rushworth, Simon; Hussain, Tanvir

Authors

Daniel Tejero-Martin

Zdenek Pala

Simon Rushworth

Tanvir Hussain



Abstract

Solution precursor thermal spray can become a breakthrough technology for the deposition of coatings with novel chemistries; however, the understanding of the process that the feedstock material undergoes is still lacking when compared to more traditional presentations (i.e. powder and suspension). In this paper, niobium-doped TiO2 coatings were deposited by solution precursor high velocity oxy-fuel thermal spraying, studying its microstructure and phase. It was reported that a lower flame temperature produced a highly porous coating, while the porosity was reduced at higher flame temperature. Investigation of the phase content showed that, contrary to our current understanding, a higher flame power implied an increase of the anatase phase content for solution precursor spray. Three methods were used: Rietveld refinement, peak height and peak area of the x-ray diffraction patterns. Additionally, single splats were analysed, showing that as the precursor travels through the flame, pyrolysis and sintering takes place to form the solid material. These results were used to derive a model of the physico-chemical transformation of the solution precursor. This work proves that solution precursor thermal spray is a promising technique for the deposition of doped ceramic coatings, being the microstructure and phase content controllable through the spraying parameters.

Journal Article Type Article
Publication Date Oct 31, 2019
Journal Ceramics International
Print ISSN 0272-8842
Publisher Elsevier
Peer Reviewed Peer Reviewed
Institution Citation Tejero-Martin, D., Pala, Z., Rushworth, S., & Hussain, T. (2019). Splat formation and microstructure of solution precursor thermal sprayed Nb-doped titanium oxide coatings. Ceramics International, https://doi.org/10.1016/j.ceramint.2019.10.253
DOI https://doi.org/10.1016/j.ceramint.2019.10.253
Keywords Solution precursor; HVOF; Niobium; Titanium oxide; Anatase; Single splat
Publisher URL https://www.sciencedirect.com/science/article/pii/S027288421933127X#ack0010

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