The Mechanisms of Non-Oxide Ceramic Corrosion in Combustion Gases at Temperatures above the Dew Point of Salts

摘要

The general corrosion route of two non-oxide ceramics has been investigated, and the similarities and differences of their behaviour are discussed. A test procedure was developed that would allow the close examination of the effect of salt vapours on corrosion. Contaminants from the gas phase were incorporated into the scale, enhancing the rate of corrosion. Indigenous impurities in the starting material migrated into the corrosion product where they altered the chemical and physical properties of the scale. There was strong evidence to support the sodium oxide activity as being the main parameter determining corrosion rates.