16. November 2020 | Application area
Scientists describe stainless steel prepared by high voltage powder spraying and its adhesion phenomena.
Scientists prepared titanium-coated stainless steel containing carbon. Image source: artbaggage – Pixabay (symbol image).
Nowadays, many studies relate to coating materials on stainless steel prepared by various methods, and many approaches have been taken to improve the abrasion resistance of coatings. Here, the fixation of carbon/titanium (C/TiO2) on stainless steel and the evaluation of its coating adhesion is reported.
Commercially available epoxy resin was used as the carbon source, and the transformation of epoxy resin into pyrolytic carbon was carried out. It is proposed that the incorporation of an inorganic particle improves adhesion properties by reducing carbon shrinkage. C/TiO2 was prepared from the mixture of commercial epoxy resin and TiO anatase2 powder, followed by spraying the mixture onto a stainless steel (AISI 304) surface using high voltage powder spray coating (HVPSC).
Multi-temperature pyrolysis
The powders sprayed on the stainless steel underwent pyrolysis at several temperatures from 300 to 700°C for one hour in order to determine the optimum temperature for excellent adhesion. The physical properties of C/TiO2 coated samples were characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), surface profiler and X-ray photoelectron spectroscopy (XPS). FTIR analysis of C/TiO2 coating identified the appearance of CH sp peaks3, CO, CO and TiO. It was noticed that the absorption band of CH sp3, CO, and CO slowly disappeared as the pyrolysis temperature increased, indicating that the structure had changed from epoxy to pyrolytic carbon. FESEM images showed that TiO2 the particles were completely covered with the carbon layer and the thickness was determined to be between 4.8 and 15.5 μm.
The abrasive and peel adhesion test was performed, showing no detachment of the C/TiO coated material2 pyrolyzed at 300°C, suggesting that this temperature produces the best coating adhesion. The adhesion phenomena of the carbon-based coating were elucidated by XPS analysis of the peaks of the elements Fe2p, C1s and Ti2p. The presence of an oxide layer on the stainless steel, the availability of functional groups and the shrinkage of the structure have been shown to be the factors that affect the adhesion of the carbonaceous coating.
The shrinkage of the structure has been reduced thanks to the presence of TiO2, which is associated with high adhesion of the coating. This demonstrated that the carbonaceous coating produced by HVPSC formed excellent adhesion in the presence of TiO2.
The study was published in Progress in Organic Coatings, Volume 147, October 2020.
