THE NEED FOR STANDARD TEST METHODOLOGIES FOR HIGH-TEMPERATURE CORROSION - SIMULATING GASEOUS CORROSION PROCESSES

Corrosion is a major factor affecting the selection, efficiency and sa fety of many processes operating at elevated temperatures. This is par ticularly the case in coal gasification plant where a number of contam inants derived from the coal feedstock can cause severe degradation th rough corrosive attack. Testing of materials for inclusion in such pla nt can be undertaken in situ or in the laboratory under simulated plan t conditions. The latter method is commonly used owing to the need to establish, in a controlled manner, the mechanisms governing the mode a nd rate of the corrosion degradation processes. The paper describes th e development of laboratory test methodologies that simulate specific elements of corrosion processes occurring under real plant conditions, allowing predictive models for materials behaviour to be developed. A n important aspect of the laboratory studies is the development of tes t methodologies that permit close control of experimental parameters a nd have the capability of being reproduced not only in the same labora tory but in other laboratories. Fully reproducible test methodologies could eventually be used as standards. If accepted standard test metho ds for obtaining commercially relevant data can eventually be establis hed, the database for candidate and new materials should grow and, as a result, better provide for future plant design and operating require ments.