STP866

    Developing an Accelerated Test: Problems and Pitfalls

    Published: Jan 1985


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    Abstract

    Naval aircraft spend considerable time on the decks of aircraft carriers exposed to sea spray and sulfur-bearing stack gases. A series of exposure tests of various aircraft materials and coatings have been conducted on operational carriers for over five years. There were two objectives for this work: (1) to find out how the materials behaved in the hostile carrier environment and (2) to develop a laboratory test to simulate that environment. The first objective is being successfully met. The second objective is more difficult to achieve.

    To date, experiments have included use of a salt fog chamber with periodic introduction of sulfur dioxide gas. Various cyclic conditions have been studied. such as spraying salt fog, introducing sulfur dioxide gas followed by a soak period at high humidity. This cycle reproduces in two weeks the exfoliation attack on susceptible aluminum alloys that occur on a carrier in about eight months. However on cadmium plated steel, which undergoes little or no attack on the carrier, this cycle causes considerable attack on the coating. Since an accelerated test is also desired for materials, such as paints, corrosion preventive compounds, sealants, and other organics used on naval aircraft, finding one accelerated test that will reproduce carrier results on such a wide variety of materials presents a formidable task.

    Keywords:

    accelerated tests, corrosion tests, corrosion environments, salt-sulfurdioxide environments


    Author Information:

    Ketcham, SJ
    Head of Materials Protection Branch (now retired) and chemist, Aircraft and Crew Systems Technology Directorate, Naval Air Development Center, Warminster, PA

    Jankowsky, EJ
    Head of Materials Protection Branch (now retired) and chemist, Aircraft and Crew Systems Technology Directorate, Naval Air Development Center, Warminster, PA


    Paper ID: STP33767S

    Committee/Subcommittee: G01.05

    DOI: 10.1520/STP33767S


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