ISO/TC 156/WG 13 - High temperature corrosion

This document describes the general procedure for electrochemical measurements in high-temperature molten salts using potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS), and describes the experimental apparatus.

This document specifies the thermogravimetric method (continuous measurement) for isothermal and cyclic exposure of metals and metallic alloys at high temperature under corrosive conditions.

ISO 17245:2015 specifies the method for high temperature corrosion testing of metallic materials by immersing in molten salt or other liquids which are under static conditions and exposing them to high temperature in a controlled gas environment to evaluate their corrosion resistance. Two options are considered: a) using a stagnant inert gas environment, and b) using a flowing reactive gas environment. ISO 17245:2015 does not cover methods where test pieces are fully or partially embedded in a corrosive powder made up of salt, ash, and/or other solids, or cases in which a surface deposit is applied to the specimens. These methods are covered in ISO 17248 and ISO 17224, respectively. ISO 17245:2015 is not applicable to the situation of test pieces in relative movement to their surrounding corrosive liquid.

L'ISO 17224:2015 spécifie la méthode utilisée pour les essais de corrosion à haute température de matériaux métalliques par application d'un dépôt de sel, de cendres et/ou d'autres substances, en les exposant à des températures élevées dans un environnement gazeux contrôlé afin d'évaluer leur résistance à la corrosion. Le dépôt est appliqué avant l'exposition aux températures élevées par pulvérisation, trempage ou peinture. L'ISO 17224:2015 ne traite pas des méthodes dans lesquelles les éprouvettes d'essai sont entièrement ou partiellement enfouies dans des substances corrosives ou immergées dans des liquides. Ces méthodes sont traitées dans l'ISO 17248 et l'ISO 17245, respectivement.

ISO 17248:2015 specifies the method for high temperature corrosion testing of metallic materials by embedding in a corrosive powder made up of salt, ash, and/or other solids and exposing them to high temperature in a controlled gas environment to evaluate their corrosion resistance. Two options exist: fully embedding and partially embedding. Fully embedding is used in cases in which a mass change measurement is required. Partially embedding is used to investigate three potentially different interaction zones on a single test piece, i.e. the embedded part, the non-embedded part, and the gas/powder interface region. Therefore, gravimetric measurements are not appropriate and metallographic investigations are necessary instead. ISO 17248:2015 does not cover methods where test pieces are immersed in a liquid or cases in which a surface deposit is applied to the test pieces. These methods are covered in ISO 17245 and ISO 17224, respectively.

ISO 26146:2012 covers examination of samples that have previously been exposed to corrosive environments at high temperatures. ISO 26146:2012 covers the classification, identification, and thickness measurement of any corrosion layer forming during the exposure.

ISO 13573:2012 describes the methodology for thermal cycling corrosion testing (known as cyclic oxidation testing) of metallic materials in gaseous environments between ambient and elevated temperatures (series of measurements on a single test piece with repeated, regular and controlled temperature cycles). ISO 13573:2012 may be applicable to other materials with some modifications. Tests with ultra short dwell times in the range of minutes or seconds are outside the scope of ISO 13573:2012.