Corrosion tests aluminium alloys

Budd and Booth found the potentiostatic test best for investigating the intergranular and layer corrosion of aluminium alloys. 

Some understanding of the corrosion of aluminium alloys used as cladding on research and test reactor fuel has been obtained from the CRP. Aluminium corrosion is extremely complex and the variables affecting localized corrosion (pitting and crevice corrosion) act both independently and synergistically. Additional information about the effects of deposited particle composition on the corrosion behaviour of aluminium alloys is needed. Surface finish affects the corrosion of aluminium alloys, and more information is required with respect to this parameter. Additional data on the effects of certain impurity ions in basin water on localized corrosion behaviour are necessary to better identify the ions that cause corrosion. A goal would be to develop an equation for pitting as a function of water chemistry parameters. 

The IAEA compiled a thorough state of the art literature review on corrosion of aluminium alloys in 1998. This review was published in lAEA-TECDOC-1012, Durability of Spent Nuclear Fuels and Facility Components in Wet Storage [2.1]. It presented a wide range of quantitative and semi-quantitative data on nuclear fuel cladding alloys and included sections on corrosion of aluminium, zirconium, stainless steel, carbon steels and copper alloys in wet storage environments. Sections of the book that apply to aluminium alloys used in fuels for research and test reactors have been updated and presented in this review. 

CORROSION OF ALUMINIUM ALLOY TEST COUPONS IN THE SPENT FUEL BASIN OF THE BUDAPEST RESEARCH REACTOR AT AEKI, BUDAPEST, HUNGARY... 

Corrosion of metals and alloys—Corrosivity of atmospheres—Guiding values for the corrosivity categories Corrosion of metals and alloys—Corrosivity of atmospheres—Measurement of pollution Corrosion of metals and alloys—Corrosivity of atmospheres—Determination of corrosion rate of standard specimens for the evaluation of corrosivity Corrosion tests in artificial atmospheres—Salt spray tests Nickel-based alloys—Determination of resistance to intergranular corrosion Corrosion of aluminium alloys—Determination of resistance to stress corrosion cracking Corrosion tests in artificial atmosphere at very low concentrations of polluting gas(es)... 

Testing corrosion of exfoliation corrosion of aluminium alloys Determination of susceptibility to exfoliation corrosion of alloys of the 2000 and 7000 series alloys (EXCO)... 

The tested aluminium alloys have very good corrosion resistance in contact with surface seawater. For example, the extrapolated decrease in thickness after 30 years would be on the order of 200 xm for alloys 3004 and 5052. In contact with deep seawater, the same alloys exhibit pitting corrosion with a depth up to 200 p.m after 3 months of operation [33]. 

In addition to examining pre-exposure effects, the slow strain-rate testing technique has been used increasingly to examine and compare the stress-corrosion susceptibility of aluminium alloys of various compositions, heat treatments and forms. A recent extensive review draws attention to differences in response to the various groups of commonly employed alloys which are summarised in Fig. 8.57. The most effective test environment was found to be 3 Vo NaCl -F 0.3 Vo HjOj. The most useful strain rate depends upon the alloy classification. 

The oxygen concentration of the solution, as in many instances of corrosion, can also be critical in stress-corrosion cracking tests. Instances are available in the literature that show very markedly different test results according to the oxygen concentration in systems as widely different as austenitic steels immersed in chloride-containing phosphate-treated boiler water and aluminium alloys immersed in 3% NaCl. 

Test method for corrosion of cast aluminium alloys in engine coolants under heat-transfer conditions... 

Test method for exfoliation corrosion susceptibility in 2XXX and 7XXX series aluminium alloys (EXCO test)... 

Recommended practice for examination and evaluation of pitting corrosion Test method for determining susceptibility to stress corrosion cracking of high-strength aluminium alloy products Test method for pitting and crevice corrosion resistance of stainless steels and related alloys by the use of ferric chloride solution Recommended practice for preparation and use of direct tension stress corrosion test specimens... 

Method for visual assessment of exfoliation corrosion susceptibility of 5XXX series aluminium alloys (Asset test)... 

Test method for determining the susceptibility to intergranular corrosion of 5XXX series aluminium alloys by mass loss after exposure to nitric acid (NAMLT test) Practice for liquid sodium corrosion testing of metals and alloys... 

Practice for measurement of corrosion potentials of aluminium alloys Practice for conducting and evaluating galvanic corrosion tests in electrolytes Practice for liquid impingement erosion testing... 

Chemical and Electrochemical Corrosion of Pile Materials Under Radiation, Since uranium is readily oxidized, it must be protected from the water by a sheath or coating. Also, for the external cooling, a lining tube must be placed in the graphite. With water as the coolant, these two (the sheath and tube) must be of the same material or of two materials close together in the electrochemical series to suppress electrochemical corrosion. Of the few suitable materials, which have low danger coefficients and are not attacked appreciably by hot water, etc., the most promising are, in order, beryllium and aluminimn. While the former is more desirable also for its hardness and resistance to wear, the limited supply of beryllium available plus the lack of commercial development make aluminium with its more extensive commercial production and development practically the only alternative, imtil such time as beryllium or beryllium-aluminimn alloys can compete or surpass aluminium or unless further corrosion tests prohibit the use of aluminium and force the development of Be or Be-Al. 

Hudson reported lives of about 4y years for 38 /tm thick metal-sprayed aluminium coatings on steel exposed at Sheffield, and more than 1 ly years for coatings 75/tm thick. Sprayed aluminium coatings (approximately 125/tm thick) have also provided complete protection against exfoliation and stress corrosion to aluminium-copper-magnesium (HE 15) and aluminium-zinc-magnesium (DTD 683) alloys in tests lasting up to 10 years in industrial and marine environments . 

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