Preparation And Property Of Anti-corrosion Functional Bis-silanes Films On 0Cr18Ni9 Stainless Steel

The absorption heat transformer (AHT) is a energy conservation technology which converts low level energy and exhaust heat into high level energy. It has attracted more attention in the world-wide energy crisis recent years. Lithium bromide solutions, the commonly used absorbent solutions in heating and refrigerating absorption systems, can cause serious corrosion problems on metallic component, especially at high temperature, which has seriously restricted the development of AHT at high temperature.In this paper, functional bis-silanes BMBSE films were successfully prepared on 0Crl8Ni9 stainless steels substrates by Czochralski Method. The surface morphologies and structures of the film were studied by means of scanning electronic micrographs (SEM), contact angle measurement, Fourier transform infrared spectroscopy (FT-IR), and Electron probe x-ray micro analyzer (EPMA). The results showed that a perfect BMBSE film was produced by deposition of molecules attached to the metal surface by chemical bonds of Si-O-Fe between the BMBSE film and the 0Cr18Ni9 stainless steel. Meanwhile, the coated surface was hydrophobic with a contact angle of 107.2°since the introduction of methyl groups and methylene groups. Static immersing corrosion test, potentiodynamically polarization curve and electrochemical impedance spectroscopy (EIS) were conducted to evaluate the film corrosion performances. The results of potentiodynamically polarization curve and EIS in 55wt% LiBr solutions at room temperature in atmospherical pressure indicated that the corrosion current density of BMBSE film coated surface was 4 orders of magnitude smaller than that of bare SUS304 steel, and the impedance was increased by a factor of 10000. Static immersing corrosion test presented that the BMBSE film can significantly increase the corrosion resistance in 55wt%LiBr solution at 180°C compared with stainless steels.Furthermore, tetraethyl orthosilicate (TEOS) was added to improve the structure of BMBSE film. A hydrophobic composite film of BMBSE/TEOS was successfully prepared on 0Cr18Ni9 stainless steels substrates. The results showed that the introduction of TEOS increased the crosslinkage between composite films and substrates which led to a denser layer and further improved the anti-corrosion property of 0Cr18Ni9 stainless steels. The anti-corrosion property of BMBSE/TEOS composite film tended to peak with the molar ratio of BMBSE to TEOS being 2:1. Corrosion rate of BMBSE/TEOS composite film coated surface was 5.64um/a in 55wt%LiBr solution at 180℃, which was better than of BMBSE film coated one.EIS was applied to investigate the corrosion process of the BMBSE film and BMBSE/TEOS composite film coated 0Crl8Ni9 stainless steels in 55wt%LiBr solution at room temperature. Both of two films exhibit an excellent corrosion resistant property with the composite film being better.