Synthesis, characterization and properties of ATO/potassium silicate film prepared by twice spray pyrolysis

Hydrophilic coatings have received considerable attentions in recent years. This study investigates an ATO/potassium silicate hydrophilic film based on antimony doped tin oxide (ATO) and potassium silicate (PS) which deposited on aluminum sheets by twice spray pyrolysis. For comparison, four groups of samples including aluminum sheets (Al), aluminum sheets deposited with ATO film (Al/ATO), aluminum sheets deposited with potassium silicate film (Al/PS) and aluminum sheets deposited with both ATO and potassium silicate films (Al/ATO/PS) have been used for experiments. The morphologies, phase structures and chemical compositions of four samples have been characterized using FE-SEM, AFM, XRD and XPS. The hydrophilic, anticorrosive, thermal conductive and electrical resistive properties of the four samples have been studied in detail. The results show clearly that smooth PS film possesses good hydrophilicity and the water contact angle of ATO/PS film maintains below 17° after being exposed in air for 1 month. Moreover, the ATO/PS film shows lower corrosion current density comparing with other samples, revealing its excellent corrosion resistance property. The difference in the thermal conductivity values of the four samples is not significant. And the thermal conductivity is slightly increased by 4.0% for Al/ATO/PS, compared to Al/PS. These results indicate that ATO/PS film has superior hydrophilic performance, corrosion resistance and thermal conductivity than the individual potassium silicate film and ATO film.