Open AccessCORROSION OF SOME REACTOR MATERIALS IN DILUTE PHOSPHORIC ACID
Author(s) -
J.E. Draley,
S. Greenberg,
W.E. Ruther
Publication year - 1961
Language(s) - English
Resource type - Reports
DOI - 10.2172/4015184
Subject(s) - corrosion , phosphoric acid , distilled water , materials science , carbon steel , intergranular corrosion , metallurgy , penetration (warfare) , aluminium , zirconium alloy , carbon fibers , zirconium , composite material , chemistry , chromatography , operations research , composite number , engineering
Corrosion tests in dilute phosphoric acid (pH 3.5) at elevated temperature are described for X8001 aluminum, 18-8 stainless steels, aluminized carbon steel, and Zircaloy. In a 307-day dynamic test at 18 ft/sec and 315 deg C, X8001 aluminum corroded at a rate of 1/2 mdd for the first 240 days. In subsequent exposures, the corrosion rate increased, but the total average penetration at 307 days was only 0.0005 inch. At 200 days, the total corrosion in this test was one-fiftieth that in distilled water. Static tests at 225 deg C gave corrosion rates too low to measure (<0.2 mdd). Of several different 18-8 stainless steels tested in this solution at 315 deg C, only sensitized type 316 suffered intergranular attack. General attack rates of the other samples, of the order of 1/4 mdd, were obtained for the period from 94 to 186 days. Although this is much larger than the rate in distilled water, it represents a penetration rate of only about 5 x 10/sup -//sup 5/ inch/year. Aluminized carbon steel did not suffer rapid corrosion in this solution at 315 deg C, even when large areas of the carbon steel were exposed. There was a tendency for corrosion to separate the steel and aluminum with some specimens, depending on the heat treatment. Zircaloy-2 and Zircaloy-3 corrosion were of the same order in this solution at 315 deg C as in water. (auth