Solution Precursor Plasma Spraying of TiO₂ Coatings Using a Catalyst-Free Precursor

Area of Science:

• Materials Science
• Surface Engineering
• Nanotechnology

Background:

• Titania dioxide (TiO2) coatings are crucial for various applications.
• Controlling the microstructure and phase composition of TiO2 coatings is essential for performance.
• Solution precursor plasma spraying (SPPS) offers a versatile method for depositing TiO2 coatings.

Purpose of the Study:

• To investigate the microstructural characteristics and phase composition of TiO2 coatings produced via SPPS.
• To explore the influence of precursor concentration, stand-off distance, and spray passes on coating properties.
• To optimize SPPS parameters for tailored TiO2 coating fabrication.

Main Methods:

• Utilized an ethanol-based precursor solution of titanium isopropoxide.
• Employed solution precursor plasma spraying (SPPS) to deposit TiO2 coatings.
• Analyzed coating microstructure using scanning electron microscopy (SEM) and phase composition via X-ray diffraction (XRD).

Main Results:

• Increased precursor molar concentration (0.3 M to 0.6 M) elevated the thermal behavior and phase transformation temperature.
• SEM revealed nano- and submicron-sized spherical particles on the coating surfaces.
• Higher concentrations resulted in dense coatings with micropores (5-8 µm), while increased spray passes yielded thicker coatings (16-20 µm).
• Both anatase and rutile TiO2 phases were detected, influenced by concentration, stand-off distance, and spray passes.

Conclusions:

• SPPS allows for the fabrication of TiO2 coatings with controllable microstructural and phase characteristics.
• Precursor concentration and spraying parameters significantly impact coating density, thickness, and phase composition.
• This research provides insights into optimizing SPPS for producing functional TiO2 coatings.