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GEOHEX Project Research Published in Online Journal

Mon, 27 November, 2023

Research undertaken by TWI’s Material Performance and Integrity Group alongside the University of Leicester’s Materials Innovation Centre has been published by MDPI open access journals.

The findings, which were part of the GEOHEX project, have been made available in the paper, ‘Spray Parameters and Coating Microstructure Relationship in Suspension Plasma Spray TiO2 Coatings.’

There has been an increasing interest on the use of thermal spray techniques using suspension or solution-based coatings for the precise control spray particle size and microstructure. This techniques can improve the flow of the coating feedstock and allow for high-quality coating customisation.

This is important as the feedstock flow rate and stand-off distance can impact both the performance and characteristics of coatings that are used to prevent corrosion, fouling and scaling in geothermal power plant heat exchangers.

The research saw TiO2 coatings applied to a carbon steel substrate using suspension plasma spray (SPS), which can enhance the performance of geothermal heat exchanger materials.

A scanning electron microscope, profilometry, X-ray diffraction, and adhesion testing were used to assess the impact of the feedstock flow rate and stand-off distance on the coating performance, with results demonstrating that coatings deposited with a 10mL/min flow rate were well adhered to the substrate.

However, as the stand-off distance and feedstock flow rate were increased, the poor thermal and kinetic energy between the torch and the feedstock particles led to decreased adhesion to the substrate.

You can read the paper and learn about the findings of this research in full, here.


The GEOHEX project has received funding from the European Union's Horizon 2020 research and innovation programme. Grant agreement 851917.

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