Sol-gel method for preparing micro/nano titanium dioxide and lyophobic film thereof on metal surfaces

Abstract

The invention discloses a sol-gel method for preparing micro / nano titanium dioxide and lyophobic film thereof on metal surfaces, which includes the following steps of (a) pretreating metal substrates; (b) preparing micro / nano TiO2 films on surfaces of the metal substrates which are pretreated; and (c) preparing (heptadecafluoro-1,1,2,2-tetradecyl) triisopropoxysilane-silicon dioxide lyophobic films on the micro / nano TiO2 films on the surfaces of the metal substrates. The sol-gel method has the advantages of high operability, simplicity in processing and equipment and easiness in industrialization. Besides, the titanium dioxide films are used as transitional layers so that corrosion of acid sol to the metal substrates during the process of directly coating the silane lyophobic films is avoided, wettability to silane sol is enhanced, and uniform and compact lyophobic films are prepared finally. Meanwhile, defects such as cracking and the like can be reduced by means of multiple coating processes, corrosion resistance performance of the films is improved, surface free energy of the films is decreased by lyophobic treatment, and dirt settled on the films is reduced.

Description

technical field [0001] The invention relates to a method for preparing a film on a metal surface, in particular to a method for preparing micronano titanium dioxide and a hydrophobic film thereof on a metal surface. Background technique [0002] Corrosion and scaling problems in geothermal water utilization systems have always been serious obstacles to the development and utilization of geothermal energy, and are one of the most important research topics in the world today. According to statistics, the global economic loss caused by steel corrosion is about 700 billion U.S. dollars every year, accounting for 2-4% of the gross national product of various countries; and the appearance and thickening of the scale layer will increase fluid resistance and energy consumption on the one hand. Reduce the water output and affect the normal operation. On the other hand, the incomplete part of the scale layer will cause local corrosion. In order to reduce the corrosion of equipment an...

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Problems solved by technology

For example, Japanese patent 99806905.1 and Chinese patent 200610147644.9, the obtained sol is acidic, and it will inevitably corrode the metal when sintered at high temperature. At the same time, the wettability between the hydrophobic sol and the metal substrate is poor, which affects the uniformity of the coating and is not conducive to repeated repetitions. coating

However, the Chinese patent 201010153498.7 simply uses alkyl alkoxysilane as the precursor, which is expensive and increases the cost of film production. At the same time, the roughness of the film is large, which will inevitably accelerate the deposition of dirt.

Chinese patent 200510065816.3, the resulting monomolecular hydrophobic layer is easy to fall off, the service life is short, and the method cannot adjust the thickness of the hydrophobic coating

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