Results are summarized of feasibility of using model for description of exfoliation corrosion (EC) in modeling of structural degradation of AlCu4Mg1 (Al2024) on extruded stringer type specimens in EXCO solution for different times of exposure. The effect of time for time development of this localized form of corrosion was assessed by using the approach of Robinson. Briefly, this approach makes possible description of intergrannular penetration observed under blisters formed by voluminous corrosion products. However, intergrannular stress supposed to be resulting from the expansion of corrosion products along dissolved grain boundaries is not taken into account in this model. Possible application of concept of intergrannular stress incorporation into EC model is discussed for modeling of structural degradation of Al2024 in EXCO tests.

The possible effects on the protective performance of ZRP modified by combination of Zn dust with aluminium or carbon type fillers were investigated using electrochemical noise analysis (ENA). The role of different oxygen diffusion characteristics (identified on tested coating systems with ENA) on delamination tendency was tested during 168 hrs immersion tests in 0.05 M NaCl. It was shown the protective performance of tested type of coating systems can be changing with immersion time rather differently in relation to different ability of polymer matrix with the Zn/Al or Zn/C particles combination for oxygen transport to the coating/steel interface.

This work presents results on the influence of fluoride ions on the behavior of layers whose main component is the phase TiAl0.3Si1.7 (called t2 phase), formed on TiAl6V4 substrate. Layers were prepared in AlSi20 melt at 650 ° C for 60 min. Potentiodynamic curves were measured in a chloride solution with 0 and 5000 ppm fluoride. Layer were shifted corrosion potential to more negative values and at the some time reduce the corrosion current density (Im). Values of Im are in the potential range of 300 – 1500 mV (SCE) for TiAl6V4 with Ti-Al-Si layers significantly lower in comparison with Im values found for TiAl6V4 in chloride solution containing 5000 F-. The electrochemical tests showed that Ti-Al-Si layer had marked positive effect on corrosion resistance of TiAl6V4 alloys in aggressive environment with high content of F-.

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Zinc-containing copper alloys, the so-called a þ b brasses, are commonly used in contact with potable water. These materials are alloyed with lead to improve machinability. In wrought special brass alloys, reducing the content of this alloying element or replacing it with alternative alloying additions may give rise to a new type of machinable copper alloys which differ from the original alloys by their contents of other modifier elements such as Si (or possibly, Mg, Bi, and P). These alloys have a very low content of lead required for the break-up of chips during machining. Even though these types of brass exhibit a very good machinability, the effects of their chemical composition on the resistance of the alloy to corrosion cracking have not yet been given sufficient attention. This paper aims to present an assessment of three new types of machinable copper alloys regarding their susceptibility to stress corrosion cracking, in comparison to that of the lead-alloyed variety, in 0.05 M NaCl, NaNO 2 , and Na 2 SO 4 solutions. The slow strain rate test has been used for this purpose, and its results were correlated with metallographic evaluation of the number and depth of the cracks observed on the test specimen surfaces on completion of the test.