Measuring Cr Volatility from Ferritic Stainless Steels: Novel and Conventional Methods Compared

Abstract

Reactive evaporation of Cr-species from ferritic stainless steels is a technical challenge for solid oxide fuel cell (SOFC) systems and other devices operating in high-temperature (>500°C) oxidizing environments. A traditional method for quantitatively measuring Cr volatility is by using a transpiration system, in which oxidizing gases are flown by Cr-containing materials and the exhaust is condensed and subsequently analyzed using ICP-MS. While this method is well established and accurate, it also has limited sensitivity and challenges associated with sample collection. Novel methods have recently been developed to quickly and accurately evaluate and quantify low levels of Cr volatility. These include the denuder technique, which employs a water-soluble reactive collection and optical analysis; a cold quartz wool collection method with ICP-MS; a cold Si-wafer collection with ion-beam analysis; an ionic conductivity measurement of condensed exhaust solution; and, a simple staining method. Each method has advantages and disadvantages in terms of cost, operation, sensitivity and accuracy. In this poster, Cr volatility measurement techniques will be presented and compared in the context of facilitating new and ongoing research efforts.