| Aluminum and aluminum alloy has many advantages such as low density, highspecific strength, good corrosion resistance, easy to processing molding and it has avery wide range of applications such as in transportation, industry and otherfields.Tungsten-aluminum alloy studied in this article is a new type of structuralmaterial, which is very prospect of special high temperature resistant, high hardness,high wear-resisting, high strength lightweight alloy material, and it is expected tobecome a new generation of aerospace engine structure material and marine vesselsstructural material. In order to widely use it in shipping industry and offshore platformin future, we must first test the corrosion behavior of it in seawater and comprehendits corrosion resistance.In order to reduce or even avoid the damage caused byseawater corrosion, it is necessary to take appropriate measures to improve itscorrosion resistance. But now the studies on the corrosion behavior oftungsten-aluminum alloy in seawater is still basically a blank stage. Therefore, underlaboratory conditions, we form anodic oxide film on tungsten-aluminum(W-Al) alloy,then taking desiccation procedures on it.After that we study the electrochemicalcorrosion behavior using electrochemical polarization test, salt spray test and SEMtesting in order to provide certain reference for this kind of alloy in oceandevelopment and applications in the future.Paper is divided into two parts. In the first part of the article,we form anodic oxidefilm on tungsten-aluminum(W-Al) alloy using anodic oxidation and optimize processparameters.The relatively optimal conditions were determined for30mA/cm2,70minby electrochemical polarization test and weight-loss method.In the second part of the article, a low wettability surface can be formed on W-Alalloy by anodizing and desiccation treatment.It was found that desiccation treatmentresults in large increases in the water contact angle on anodic films.In this experiment,changing the time of desiccation treatment at150℃conditions, the oxide film wassubjected to measure the water contact angle,polarization curve test, salt spray test tostudy the corrosion resistance of it. The surface morphology characterization of theoxide film is investigated by SEM. After the anodizing and desiccation treatment wecan form a low surface wettability of the surface of the aluminum alloy.The sampleafter desiccation treatment for18h has a larger water contact angle.The SEM testshows that the low wettability surface has relatively regular porous morphology.According to the polarization curves tests and the sample surface morphology afterthe salt spray test, the sample with a high water contact angle shows better corrosiveresistance in NaCl solution than the sample having a lower water contact angle. Theincrease of water contact angle of anodized film is the main reason that impedes thecorrosion reaction. |
PDF Full Text Request