Cold-Sprayed TiO₂ Coatings from Nanostructured Ceramic Agglomerated Powders

Abstract

In this work, synthesis of agglomerated TiO₂, which is ready to be used after synthesis via a simple hydrolysis process, is described. The as-synthesized TiO₂ powders were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Field Emission Scanning Electron Microscope (FE-SEM), Transmission Electron Microscope (TEM) and DTA. DTA curve indicated that addition of (NH₄)₂SO₄ into the starting precursor has accelerated the hydrolysis of titanyl sulfate. The XRD patterns showed that single-phase anatase TiO₂ was produced using low-temperature hydrolysis at 80°C. SEM confirmed that the as-synthesized powders were in agglomerated form and in micro size. Addition of a structure-directing agent (SDA), (NH₄)₂SO₄, promotes agglomeration, with a denser closed packing of particle arrangement, which reduces the number of existing porosities in the synthesized powder. The TEM image showed that the primary particles were nanoparticles. The preliminary study of coating formation depicted that the powder obtained could be used as the feedstock powder for the cold spray (CS) process to make the coating as it can be deposited onto the ceramic tile substrate.

Keywords:

• Agglomerate
• Anatase
• Ceramics
• Coatings
• Deposition
• Hydrolysis
• Nanoparticles
• Synthesis
• TiO_2.