Preparation And Study Of Hydrophobic Organosilane Complex Film On Copper Alloy Surface

Copper and copper alloys are extensively used in electronics, electrical, energy,transportation, machinery and metallurgy industries areas because of their excellentanti-fouling properties, machining performance and conductivity thermal conductivity.However, copper and its alloys are inclined to be corroded in a humid environment or thesolution containing corrosive medium（such as CN^-、NH₄⁺、Cl-et al）, which limits their scopeof application. Therefore, how to slow down the corrosion of copper and copper alloy hasbecome an important direction in the study of corrosion. In this study, the single and complexorganic thin films were prepared on copper alloy surface by combination of self-assemblytechnique and electrochemical assisted deposition technology, their structures and propertieswere characterized. The results are as follows:（1） The6-（3-triethoxysilyl-propyl）amino-1,3,5-triazine-2,4-dithiol monosodium （TES）compound was used to fabricate on copper alloy surface by self-assembly technique.Orthogonal experiment were conducted to explore the optimum film-forming parameters:alcohol-water ratio V_r=90:10, TES concentration c₁=3mmol/L, assembled solution pH=3, thehydrolysis time t₁=1h, the hydrolysis temperature T₁=40℃, the nitric acid concentrationc2=3mol/L, the etching time t₂=30s, the assembling time t₃=1h, the curing time t₄=30min, thecuring temperature of T₂=100℃, wherein the pH is the most important impact factor onprotection efficiency of the final assembly film.（2） The TES self-assembled film was further modified by octyl-triethoxy silane （OTES）or hexadecyl-trimethoxy silane （HDTMS） self-assembled films to obtain the complex films ofheterocyclic and long-chain organosilane. The single and composite films were analyzed byFT-IR spectra, contact angle measurement, scanning electron microscope（SEM）,electrochemistry workstation testing means. The test results showed that the contact angle ofcomplex film covered copper alloy surface was up to123.7°compared with89.4°of barecopper, thus the surface was a good hydrophobic state; the cyclic voltammogram andpolarization curves indicated that the TES/HDTMS composite film effectively improved thecorrosion resistance of copper alloy, its protection efficiency was up to96.54%.（3） TES electrodeposited film was constructed by the galvanostatic electrodeposition method on the surface of the copper alloy, the open circuit potential curve and the polarizationcurve results showed that the optimum current density to conduct TES film is0.06mA/cm².The novel electrodeposited TES film was further modified by OTES or HDTMSself-assembled films to obtain the complex films. The single and composite films’ propertieswere analyzed by scanning electron microscope, contact angle measurement andelectrochemical workstation. SEM images show that the copper alloy surface coveredTES/HDTMS composite film were more uniform compact; The cyclic voltammogram andpolarization curves indicated that the anti-corrosion performance of complex film was betterthan that of single electrodeposited TES film, and the protection efficiency was up to90.2%;Impedance data showed that the copper alloy covered by complex films’ electrochemicalimpedance value was far greater than the impedance value of the blank copper alloy, whichalso proved complex film had better protective effect for copper alloy substrate.