Preparation And Properties Of TiO₂ Films On The Surface Of 45# Steel By Sol-Gel

The surface treatment was one of the effective methods to prevent steel from corrosion.which brought great loss to the industrial production. In order to promote the corrosion resistivity and prolong the lifes of 45# steel, the TiO2 films were prepared on the surface of 45# steel through sol-gel method. TiO2 sols were prepared with Ti(OBu)4 as precusor, acetylacetone as complexation, hydrochloric acid as catalyst, alcohol as solvent. The gelation time was used as a scale standard of stability of TiO2 sol, Methods of adding water, Acac, water, alcohol, HCl and hydrolysis tempreture were investigated as affecting factors of the gelation time of TiO2 sols. The most stable sol was selected and used to the research of preparing films. The properties of dried gels which were prepared at different conditions were studied by FTIR, DTA/TG, XRD.The results showed that both of the TiO2 gels treated at 400℃ and 600℃ were anatase, but the crystal of TiO2 treated at 600℃ was more integrated than that treated at 400℃.The structure of the TiO2 treated at 600℃ were more regular than that treated at 400℃. The size of crystal treated at 400℃was about 20nm, and that treated at 600℃ was about 64nm.The TiO2 films were prepared at 400℃ and 600℃ on the surfaces of 45# steel, and the micro-structure of TiO2 coatings were studied by AFM. The results indicated that both of the films were integrated and compact, and the films treated at 600℃ was more integrated than that treated at 400℃. The corrosion behavior of coatings were evaluated through potentialdynamic polarization curves and weight loss in 1mol/L HCl.The results showed that anti-corrosion of the coatings dried at 400℃ and 600℃ were good.At 400℃,the corrosion resistivity of TiO2 coatings increased with increasing painting time,however,at 600℃,the corrosion resistivity of TiO2 coatings decreased with the increasing painting time.