STP1238

    Cosmetic Corrosion of Painted Aluminum Automotive Body Sheet: Results from Outdoor and Accelerated Laboratory Test Methods

    Published: Jan 1995


      Format Pages Price  
    PDF (308K) 18 $25   ADD TO CART
    Complete Source PDF (2.8M) 18 $55   ADD TO CART


    Abstract

    In recent years, increasing attention has been given to the need to develop an accelerated laboratory test method(s) for cosmetic corrosion of painted panels that realistically simulate in-service exposure [1,2]. Much of that work has focused on steel substrates. The purpose of this research is to compare the corrosion performance of painted aluminum sheet as determined from various laboratory methods and in-service exposure, and to determine the most realistic accelerated test method. Several aluminum sheet products from the 2xxx, 5xxx, and 6xxx alloy series have been tested. Steel substrates similar to those used in other programs [1,2] have also been included. The results indicate that of the laboratory test methods investigated, ASTM B117, Continuous Salt Spray provides the best correlation with outdoor data for aluminum alloys. For steel, however, ASTM B117 correlates poorly. In addition, there is considerable difference in the relative magnitudes and morphologies of corrosion, and occasionally in the relative rankings, as a function of test method. The influence of alloy composition and zinc phosphate coating weight are also discussed.

    Keywords:

    aluminum, steel, filiform, cosmetic corrosion, automotive, test development, zinc phosphate


    Author Information:

    Moran, JP

    Ziman, PR

    Kipp, TR
    Senior Corrosion Scientist, Technologist, and Senior Technologist, Alcoa Technical Center, Alloy Technology Division, Alcoa Center, PA


    Paper ID: STP14040S

    Committee/Subcommittee: G01.05

    DOI: 10.1520/STP14040S


    CrossRef ASTM International is a member of CrossRef.