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3786 |
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Tribological performance of nano-structured TiO2 coatings prepared by suspension HVOF spraying |
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Feifei Zhang* / National Centre for Advanced Tribology Southampton (nCATS),Engineering and the Environment,University of Southampton, UK Shuncai Wang / National Centre for Advanced Tribology Southampton (nCATS) Engineering and the Environment, University of Southampton, UK Heidi Lovelock/ TWI Ltd, Granta Park, Great Abington, , UK Ben Robinson/ Department of Chemistry, University College London, 20 Gordon Street,, UK Robert J K Wood/ National Centre for Advanced Tribology Southampton (nCATS) Engineering and the Environment, University of Southampton, UK A. Tabecki/ , |
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Research conducted during the past decade in the field of suspension thermal spraying promises an entire new class of nanostructured coatings with very different properties compared with traditional thermal spraying. The use of a suspension enables the injection of nano-sized feedstock into the flame, and reduces the flame temperature, which makes it applicable for depositing thermally sensitive materials, such as TiO2. In this study a number of parameters for suspension HVOF spraying were explored. Nano-sized TiO2 particles suspended in a water-isopropanol mixture were used to deposit coatings for tribological applications onto a type 304 stainless steel. The surface topography, cross sectional microstructure and phase composition of the deposits were characterized by scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Their sliding friction and wear behaviour were examined under humid air conditions using a reciprocating tribometer. The spray parameters used, the microstructures obtained and the dominating wear mechanisms of the nano-structured TiO2 coating are presented and discussed. |