STP1000: Atmospheric Factors Affecting the Corrosion of Zinc, Galvanized Steel, and Copper

    Cramer, SD
    Chemical engineer and metallurgist, Albany Research Center, U.S. Bureau of Mines, Albany, OR

    McDonald, LG
    Chemical engineer and metallurgist, Albany Research Center, U.S. Bureau of Mines, Albany, OR

    Pages: 19    Published: Jan 1990


    Abstract

    The Bureau of Mines, as part of the National Acid Precipitation Assessment Program, studied the atmospheric corrosion of zinc, galvanized steel, and copper at five sites in the eastern United States for periods up to five years. Air quality, meteorology, precipitation chemistry, and pariculate chemistry were monitored at each site. Long-term (steady-state) corrosion rates were measured by mass loss and by determining the rate that corrosion products were removed in precipitation runoff. A three-term runoff flux model fit long-term field corrosion data well, giving R2 values greater than 0.95. The model was based on the fluxes of precipitation volume, wet-deposited hydrogen ion, and dry-deposited sulfur dioxide that are available from regional environmental monitoring activities. The parameter values obtained from this model agreed with values obtained by direct measurement, indicating they are physically significant. These parameters are the dry deposition velocity of sulfur dioxide to the metal, the number of hydrogen ions needed to release a metal ion from the corrosion product, and a product of residence time and the solubility of the corrosion product in precipitation. Experimental evidence suggests the model needs a fourth term for the dry deposition of particulates that deposit on the metal and neutralize a fraction of the acidic species subsequently deposited. Damage to zinc, galvanized steel, and copper from wet and dry acidic deposition was estimated to be 50% or more of the total damage at each of the five sites. Damage to zinc at the Ohio site by acid deposition was more than 80% of the total damage. for copper, damage from the wet deposition of hydrogen ions was greater than that from the dry deposition of sulfur dioxide at four of the five sites.

    Keywords:

    corrosion, atmospheric corrosion, metals, copper, zinc, air quality, rain chemistry, acid rain, acid deposition, sulfur dioxide, dry deposition, deposition velocity, damage function, corrosion products


    Paper ID: STP39193S

    Committee/Subcommittee: G01.04

    DOI: 10.1520/STP39193S


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