| Copper is a kind of important industrial material and is extensively used in the field ofmanufacturing of micro-electronics, large-scale integrated circuits, wires, and heat exchangers,etc. However, because the standard electrode potential of cupper is relatively low, it exhibitsa good quality of wettability to water. Thus, it’s vulnerable to be polluted leading to theaccelerated corrosion. Nowadays, many kinds of metal protection methods havepopularized,including coating the metal surface with organic-coating which can not onlyprotect metals from corroding, but can transfer the metals’ characteristics from hydrophilic tohydrophobic, granting a self-cleaning function to the surface. If this technique is introducedinto the production, the performance of the products will greatly improve, which has broadprospect on application. This experiment chooses materials, such as, TES), CTS, HDTMS, etc.applies self-assembly technology to coat protectively composite nano-films to the copperalloys’ surface, and determine the best condition for assembly through orthogonal tests.Compared with traditional methods, this method is aiming to grant the metals a bettercorrosion resistance through a series of experiments to add binding sites between TES andsilanes, to thicken the silane-films, and to improve the uniformity, density and hydrophobicof the films. The following aspects show the results of the conditions exploring.Firstly, the best experimental conditions should be determined, which can be donethrough the orthogonal tests:(a) the best hydrolysis conditions of TES are:1.the best ratio ofalcohol-water Vr=90:10；the concentration of TES c=3mmol/L；3. the pH of assembly fluidpH=3；the optimal length of the hydrolysis time t=1h；the hydrolysis temperatureT=35℃(b)1. The length of assembly deposition time of TES on the surface of polished copper shouldbe1.5hours;2. Half an hour should be the best length of curing time;3. The curingtemperature should be at100℃. Contrasted the above conditions,it suggested that the pHeffects the protection efficiency of SAM most.(c) The CTS assembly condition are:1. theconcentration should be0.5g/L;2. the assembly temperature should be at30℃and thelength of assembly time should be0.5hours;3. The temperature of curing of the TES andlength of curing time should be representatively100℃and0.5hour.(d) the conditions of the hydrolysis of HDTMS are:1. The volume proportion V (C2H5OH): V (H2O): V(HDTMS)=95:4:1;2. the length of hydrolysis time should be24hours and hydrolysistemperature is at35℃.(e) HDTMS assembly conditions are:1. the assembly temperatureshould be35℃and the length of the assembly time should be1.5hours;2. The curingtemperature of HDTMS is150℃,and the optimal length of the curing time of HDTMSshould be also0.5hour.Secondly, we explored the characteristics of the corrosion resistance films. The result ofpolarization curve test of the coating samples in0.5mol/L NaCl shows that the protectionefficiency of the polymer film on the sample reaches97.9%, improving a lot by compared tothe protection efficiency of the non-adding-chitosan; the result of the test of coating sample in0.1mol/L NaOH shows that its cyclic voltammogram’s mathematical area is two orders ofmagnitude lower than the non-adding-chitosan which means a great improvement of itsdensity; the result of contact-angle test shows that although the contact angle reduces from79o to70o after the CTS were assembled to the TES, the contact angle of the functional film isrising up to133oafter that the HDTMS were assembled to the face of TES when comparedwith the sample covered with a monolayer of TES (contact angle:119o), which meanscomposite membrane’s hydrophobic is further enhanced. The results of contact-angle alsosuggested that the participating of chitosan can obviously improve the anti-corrosionperformance of the polymer nano-composite films. The above results are also proved by usingother methods such as scanning electron microscope, open circuit potential, and rineexperiment,ect. |
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