Accelerated corrosion tests for aerospace materials: current limitations and future trends

Abstract

Examines accelerated methods for the corrosion testing of materials, coatings and surface treatments used in the aerospace and defence industries. The drawbacks with some current accelerated corrosion tests are examined, particularly the problems experienced with neutral salt spray tests. Specific examples are given which identify the acute discrepancy between salt spray and marine exposure in the corrosion testing of metallic coatings on steels. Examines some recent advances in corrosion testing of aerospace materials, pre‐treatments and organic coatings, and outlines some preliminary research conducted at DERA Farnborough in developing more accurate test methods.

Reliability-based minimal sample factor formulation for a corrosion damage assessment in aluminium alloy plates

“…As mentioned in other publications [18][19][20], it was found that the corrosion morphology formed by the EXCO solution is similar to that formed by the field experiments, albeit the EXCO solution can achieve this in a shorter time than that formed by the field experiments. Therefore the EXCO solution is capable for the accelerated corrosion tests.…”

“…4. Since the main corrosion damage of A-alloy in field experience has been shown to be exfoliation corrosion and pitting corrosion on ageing airframes, in general, the maximum depth of the pits were regarded as the level of corrosion damage [11,14,18,19]. To measure the maximum depth of pits in each coupon, the largest part of the corrosion damage was cut off and mounted in a Bakelite puck with the damaged side exposed.…”

The Cathodic Breakdown Test to Assess Chromic Acid Anodized Aluminum Alloys Corrosion Protection Performance, in Correlation with Salt Spray (Fog) Testing

“…The combination of these four parameters in the combined CBT reduces the four cases to two cases. Accordingly, the correlation criteria were that all salt spray failures can be identified if B t < 15 seconds (s) and T 250 < 55 s or for the combined CBT when the CBT combined (sec) < 15 s. with CBT combined being a combination of the two parameters expressed in (1 From these results, Figure 7 shows also that, except for Set 1, whose data is more spread and dispersed, a relation between CBT combined parameter and the time passed in salt spray before failure can be noticed for the Al2024-T3 bare sealed. In fact, the more the set resists the corrosion attack in the salt spray cabinet, the bigger are the CBT combined values.…”

Reduction of reliability testings of data-measuring system due to its functional redundancy

“…Згодом нові рішення пробле-ми та розвиток багатьох положень, був відображений у працях інших дослідників, наприклад, [4,5]. Крім того, проблемою також займалася значна кількість зару-біжних науковців (див., наприклад, посилання у [6,7] та [8][9][10][11][12][13][14]). Роботи [4,5] покладені в основу проведе-ного дослідження.…”