STP859

    Polarization Studies on Surgical-Grade Stainless Steels in Hanks' Physiological Solution

    Published: Jan 1985


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    Abstract

    The corrosion resistance of a wrought Type 316L stainless steel (WSS316L) and a surgical-grade stainless alloy (SG2SA) were studied. The behavior of the alloys, as influenced by chloride (Cl) and bicarbonate (HCO3) ion concentrations, as well as pH and temperature in Hanks' physiological solution, were explored using electrochemical techniques.

    The results show that SG2SA exhibited a more noble response and higher passive breakdown potential than WSS316L. Both materials were significantly affected by changes in Cl and HCO3 ion concentrations. The corrosion and breakdown potentials shifted to more negative values with increasing Cl ion concentrations, but to more positive values with increasing HCO3 ion concentrations. The alloys displayed most noble characteristics in neutral solutions and at higher temperature conditions.

    The alloys were found to be active only in highly acidic solutions at potentials below −300 mV versus saturated calomel electrode (SCE). Furthermore, the materials were found to experience an early passive film breakdown at higher temperatures, indicating that the passive film is more stable at lower temperatures.

    Cyclic polarization tests on WSS316L showed that the chance of repassivation of actively growing pits is very limited in environments containing variable Cl and HCO3 ion concentration as well as at higher temperature.

    As both of the test materials were determined, from chemical analyses, to conform to AISI Type 316L stainless steel, the observed differences in corrosion behavior are explained on the basis of different chemical composition and microstructural differences as observed by metallographic analyses.

    Keywords:

    corrosion, pitting, surgical implants, stainless steel, implant materials


    Author Information:

    Ogundele, GI
    Graduate student and adjunct associate professor, The University of Calgary, Calgary, Alberta

    White, WE
    Graduate student and adjunct associate professor, The University of Calgary, Calgary, Alberta


    Paper ID: STP33246S

    Committee/Subcommittee: F04.19

    DOI: 10.1520/STP33246S


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