STP947: Marine Atmospheric Corrosion Museum Report on the Performance of Thermal Spray Coatings on Steel

    Kain, RM
    Corrosion scientist and senior research technologist, Wrightsville Beach, NC

    Baker, EA
    Corrosion scientist and senior research technologist, Wrightsville Beach, NC

    Pages: 24    Published: Jan 1987


    Abstract

    Corrosion control is usually implemented by alloy upgrading or material substitution, environmental modification or providing a protective barrier or sacrificial surface or both. Historically, the coatings approach has been the predominant first choice based on initial economics. Current and emerging coating technologies are continuing to expand the methodology and perfection of metallic and inorganic coatings.

    Plated metal, chemical conversion coatings, and flame sprayed zinc and aluminum have been used for many years to protect steel and other metals. The thermal spraying approach is well suited for larger structures as coatings may be applied in the shop or field. Newer processes, such as vapor deposition and ion implantation, for now at least, are likely to be limited to providing improved corrosion resistance for smaller, critical components.

    Regardless of the type or method of coating, anticipated performance over the lifetime of the equipment is based on laboratory testing and field trials. In this regard, long-term exposures in a variety of industrial and marine environments have been a recognized approach to characterizing coating performance.

    In the early 1950s, a number of zinc-aluminum compositions were applied to carbon steel using then-current practice and exposed at several test sites in England and the United States. The performance of these test panels was described by Hoar and Radovici following 10½ years of exposure. In the ensuing years, a number of the original panels remained on exposure at Kure Beach, NC, in the LaQue Center for Corrosion Technology, Inc., marine atmospheric exposure site.

    This paper describes the protection afforded by the various coatings after 34 years of continuous exposure in the moderately aggressive marine location situated 250 m from the Atlantic Ocean. Several electrochemical methods presently in use are reviewed in a reflection of how accurate they might be in forecasting the effectiveness of these coatings.

    Keywords:

    corrosion resistance, marine atmospheres, thermal spray coatings, single element powder, multi-metal power, mixed power, alloy powder, steels, electrochemical behavior


    Paper ID: STP20039S

    Committee/Subcommittee: B08.01

    DOI: 10.1520/STP20039S


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