An electrical resistance method was adapted to test both aluminum and zinc die cast materials in tap water, detergent solutions, and detergent solutions plus bleach. Since the rate of attack of these materials in aqueous media is sometimes low, with consequent small resistance changes, low resistance circuitry is necessary. Plotted data show comparative corrosion resistance of zinc and aluminum materials and establishes the technique satisfactory for the intended use. Conclusions reached are: (1.) In all three test media the aluminum-silicon alloy No. 13 and the aluminum-silicon-magnesium alloy No. A360 are superior to the aluminum-copper-silicon alloy (A380) and the zinc die-cast material (D3.),(2.) In solutions of detergent (not chlorinated) a reasonable amount of inhibition is conferred by the silicates which are present, (3.) No. 13 (aluminum-silicon) alloy appears to offer the maximum resistance to corrosion and No. 360 (aluminum-silicon-magnesium) alloy the next best. (4.) The method offers a satisfactory laboratory means of comparing corrosion resistance of metals. 2.3.5
Corrosion of Die Casting Alloys in Detergent Solutions Measured by Electrical Resistance Method⋆
H. J. SMITH since 1955 has been with General Electric Company’s Metallurgy and Ceramics Laboratory, Major Appliance and TV Receiver Division, Appliance Park, Louisville, Ky. For six years he was employed as a chemist and metallurgist at Fairmont Aluminum Co. in West Virginia. He later worked as a metallurgist at Tube Turns Plant No. 2. in Louisville and still later served as Assistant Works Metallurgist of International Harvester’s Louisville Works. Mr. Smith is chairman of NACE’s Ohio Valley Section, and past chairman of ASM’s Louisville Chapter. He attended Fairmont State College (AB degree, 1937) and West Virginia University.
R. L. HADLEY is Engineering Manager of General Electric Co’s Metallurgical and Ceramic Development Group, Major Appliance Laboratory, Louisville, Ky. He received a BS Met. E. from Purdue University in 1942, and MS and PhD degrees from Carnegie Institute of Technology. Dr. Hadley was employed from 1949 to 1954 as research associate at Genera) Electric Research Laboratory, The Knolls, Schenectady, N. Y. During World War II he served for four years in the U. S. Army.
