| Aluminum and aluminum alloy has a very wide range of applications such as intransportation, industry, agriculture, medicine and other fields due to manyadvantages such as low density, high specific strength, good corrosion resistance, easyto processing molding. The material studied in this article is a new type of structuralmaterial-tungsten aluminum alloy, which is very prospect of special hightemperature resistant, high hardness, high wear-resisting, high strength lightweightalloy material, is expected to become a new generation of alloy armor material andaerospace engine structure material. As a kind of new structure material with excellentproperties it will be widely used in the development of the ocean in future. If we wantto use this kind of material in the complex ocean environment, first of all we need tounderstand its corrosion behavior in the seawater in order to avoid or reduce theharms brought by corrosion. Before that the report on the corrosion behavior of thiskind of the alloy in seawater or simulated seawater did not appear. Therefore we studythe electrochemical corrosion behavior using weight loss method and electrochemicalmeans such as electrochemical polarization test, electrochemical impedancespectroscopy, electrochemical noise spectrum in different NaCl solutions underlaboratory conditions, and taking2024aluminum alloy and pure aluminum as acomparison, in order to provide certain reference for this kind of alloy in oceandevelopment and applications in the future.Paper is divided into four parts. By the traditional method of testing the tungstenaluminum alloy in3.5%NaCl solution (pH=7, t=25°C) in the corrosion rate and weget its corrosion rate size is0.077mm/a, analyzing it has good corrosion resistance in the first part of the article.The electrochemical features of the corrosion of W-Al alloy in NaCl solutionsunder different temperature (0°C,25°C,40°C,60°C), salinity (2%wt.,3.5%wt.,5%wt.,6%wt.), pH values (pH=3,5,7,9,11) were studied by electrochemical meanssuch as electrochemical impendence spectroscopy (EIS) and potentiodynamicscanning (PDS) in this paper. The experimental results show that the corrosion rate ofW-Al alloy increases with the increase of salinity and its corrosion resistance dropsalong with the increase of temperature. The alloy shows better anti corrosionperformance in the neutral NaCl solution than in other solution and its corrosion rateis accelerated with the increase of acidity of solution. Obvious passivationphenomenon occurs in the alkaline solution. Compared with the2024aluminum alloyand industrial pure aluminum, tungsten aluminum alloy is the worst anticorrosionmaterial, only in alkaline conditions is it better than the other two materialsThe third part of the article is through electrochemical impedance spectroscopy,electrochemical noise spectrum measurements of the corrosion process of tungstenalloy for different time of observational studies. Early soaking, tungsten alloy maincorrosion forms of spot corrosion, polarization resistance decreases with immersiontime, the inductance of arc also showed a trend of shrinking; Noise mapping liftingcharacteristics of repeatedly, white noise levels in pitting degree as the soaking timeappeared the trend of the change from strong to weak.Aluminum oxide film is easy to form in the air, but the protection of this kind ofporous oxide film is very small. The end of the article explores the anodic oxidationof tungsten oxide film of aluminum alloy prepared by the process parameters, therelatively optimal conditions were determined for20mA/cm2,70min, and based onthis preliminary study the hot water seal effect on the corrosion resistance of oxidefilm, learned that closed time is a good way to increase the corrosion resistance ofoxide film. |
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