The usefulness of accelerated laboratory tests for selecting materials for applications where corrosion is likely to be the main life limiting concern can be compromised by subtle, often ignored, microstructural and microchemical factors. Residual deformation and crystallographic orientation are metallurgical factors which can have a large effect on corrosion response and therefore must be considered when comparing materials. Microchemical differences are often addressed but there is still scope for'improvement here. Less commonly used microprobing techniques such as secondary ion mass spectrometry (SIMS) can provide additional information on the segregation of trace impurities which can have an important influence on corrosion resistance.
Another difficulty with accelerated tests is that high levels of acceleration often mask differences in corrosion response. This may lead to the best candidate material for the service environment not being selected. To minimize this problem the accelerated test should simulate as closely as possible the service environment. This may mean that data will take longer to obtain, however, this is the inevitable price of a greater degree of confidence in the material that is finally selected.