| Abstract: |
Coatings of Polyether-ether-ketone (PEEK) have been produced using High Velocity Air Fuel (HVAF) Thermal Spray technique. These coatings have been produced at 50mm and 100mm nozzle lengths and 200mm, 300mm and 400mm gun to substrate distances, on stainless steel 304 substrates. The techniques used to characterise and determine the extent of thermal degradation of the PEEK coatings are Valence-Band XPS and FTIR-ATR. Valence-band XPS shows that in general there is minimal degradation of the PEEK during the HVAF thermal spraying process. FTIR-ATR results show that at 200mm gun to substrate distance for both nozzle lengths there is more surface degradation of the PEEK coating than at the larger gun to substrate distances. Specifically absorption bands appeared at 2918 and 2850 cm-1, which correspond to alkane ?CH2- asymmetric stretching modes in the spectra of the 200 mm gun to substrate runs. The resolution of the 672 cm-1 peak, which corresponds to C-H vibrations on the phenyl ring, increased from one to two peaks in the spectra of the 200mm and 300 mm gun to substrate runs. This indicates a structural change in the phenyl ring possibly indicating a change in the extent of crystallization of the PEEK polymer.
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