Synthesis and characterisation of high-purity alumina achieved through a dip coating process

This study focuses on the synthesis of alumina using a modified citrate method. The chelation process involved thermal activation through biphasic drops, employing the hydrated aluminium nitrate precursor and citric acid complex. The thermal behaviour of the resulting gel was investigated using DSC/TGA followed by FTIR, which revealed absorption bands at distinct temperatures leading up to the formation of white crystallised alumina powder at 1000 degrees C. Structural analysis via XRD parameters indicated that the obtained sample is refined in the hexagonal system with the R-3C space group. SEM observations demonstrated morphology akin to an overlapping hive, highlighting significant stoichiometric purity. The semi-colloidal sol was applied in a dip-coating method to reinforce the matrix of a steel substrate, specifically E335. SEM-EDS analyses revealed the adhesion recorded as a brittle intermetallic phase. Additionally, a transformation of 22% haematite to magnetite was observed under the conditions of coating. Synthesis of nano-powder alumina by sol gel.Morphology and structure characterised by FTIR and SEM and X-ray diffraction.Dip coating process of final powder alumina on E335 steel substrates.