Influence of thermal curing on the fabrication and properties of thin organosilane films coated on low carbon steel substrates

Silane coupling agents seem to be one of the most promising alternatives for the chromium and phosphate mainly due to its excellent corrosion protection and adhesion properties to organic coatings and a non-toxic pretreatment. The organosilane film was produced by thermal curing after low carbon steel substrates were immersed in γ-glycidoxypropyltrimethoxysilane (γ-GPS) solution. The present paper is intended to provide a deeper insight into the effect of thermal curing on the fabrication and properties of this film. Characterizations of the film were performed by energy dispersive X-ray spectrometer (EDS) and reflection–absorption infrared spectroscopy (RAIR). The adhesion of the film to the substrates was also tested by pull-off method. The analytical results from EDS showed that the distribution of silicon and iron atomic concentration changed with the curing temperature. The maximum adhesion of 3.65 MPa was obtained for films cured at 150 °C for 1 h. Results of RAIR showed that the thermal curing had a great effect on the chemical structure of the films, and the reaction between silanols caused to the formation of dense films with siloxane bonds.