STP1335: Testing of Organic Acids in Engine Coolants

    Weir, TW
    Senior research chemist, ARCO Chemical Company, Newtown Square, PA

    Pages: 16    Published: Jan 1999


    Abstract

    The effectiveness of 30 organic acids as inhibitors in engine coolants is reported. Tests include glassware corrosion of coupled and uncoupled metals, FORD galvanostatic and cyclic polarization electrochemistry for aluminum pitting, and reserve alkalinity (RA) measurements. Details of each test are discussed as well as some general conclusions. For example, benzoic acid inhibits coupled metals well but is ineffective on cast iron when uncoupled. In general, the organic acids provide little RA when titrated to a pH of 5.5, titration to a pH of 4.5 can result in precipitation of the acid. Trends with respect to acid chain length are reported also.

    Keywords:

    corrosion, organic acids, long-life, coolants, glassware corrosion, electrochemistry, lead, copper, brass, cast iron, aluminum, steel


    Paper ID: STP38236S

    Committee/Subcommittee: D15.04

    DOI: 10.1520/STP38236S


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