| Autor: |
R.S. Oakley, K.R. Stokes, J.C. Galsworthy, G.S. Fox |
| Rok vydání: |
2007 |
| Předmět: |
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| Zdroj: |
Corrosion Behaviour and Protection of Copper and Aluminum Alloys in Seawater (EFC 50) ISBN: 9781420054095 |
| DOI: |
10.1533/9781845693084.3.119 |
| Popis: |
Publisher Summary This chapter presents that cast Nickel–Aluminum Bronze (NAB) finds wide application in naval vessels, being of a Cu-10 % Al-5 % Ni-5 % Fe formulation, with a general corrosion rate of 0.06 mm/year and high resistance to cavitation and impingement erosion damage. NAB is a complex alloy with several intermetallic phases. The chapter presents a figure indicating the phases normally found in heat-treated NAB castings to naval standards, where no κI is found and any retained β phase has been removed by the heat treatment. Problems have been encountered with degradation of the alloy through the action of selective phase corrosion, where preferential corrosion of the κIII lamellar inter-metallic phase results in the loss of mechanical strength from areas of the alloy so affected. Previous studies have used long-term seawater immersion to investigate the effectiveness of post-casting heat treatments on the selective phase and general corrosion of NAB which, although realistic, are restricted in the temperature and seawater chemistry obtainable at a single test site and do not provide rapid results to evaluate specific changes in alloy metallurgy or the corrosivity of the environment. Faster evaluation of the seawater corrosion behavior of NAB is required; therefore, electrochemical evaluation methods previously successfully applied to studies of stainless steel corrosion were considered for application to NAB. The chapter discusses long-term and accelerated corrosion testing methods for cast NABs in seawater. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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