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| Abstract No.: |
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| Title: |
Sliding wear investigation of plasma and high velocity oxy-fuel sprayed alumina coatings
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| Authors: |
Rehan Ahmed / Heriot-Watt University, Great Britain
Ali Omar* / Heriot-Watt University, UK
Hussain Alawadhi/ University of Sharjah, UAE
Mohamed Shameer/ University of Sharjh, UAE
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| Abstract: |
Alumina coatings display a multitude of properties such as resistance to chemical reactions and thermal barrier properties as well as wear resistance. This paper investigates the sliding wear resistance of thermally sprayed alumina coatings produced using two different processes of High Velocity Oxy-Fuel (HVOF) and Air Plasma Spray (APS). Coatings were deposited on AISI 440C stainless steel substrates using two different types of feedstock powder, with fine powder used for HVOF spraying and conventional sized powder for APS. Sliding wear tests were carried out using ASTM G133-02 standard using sintered WC-6Co ball as the counter-body. Coatings were characterized using Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) and nano-indentation technique. Both coatings showed the presence of ±- and ³- phases, where APS coating had mostly ³-phase and HVOF coating had mostly ±-phase. Regions of wear track were analysed using SEM to observe the wear mechanisms. HVOF coatings showed better wear resistance than APS coating. The lower performance of APS coating is attributed to the presence of ³-phases and higher porosity when compared to HVOF coating. Results are discussed in terms of structure-property relationships.
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