Isothermal oxidation behavior and growth kinetics of suicide coatings formed on Nb-1Zr-0.1C alloy

摘要

Isothermal oxidation behavior of the single layer NbSi2 and the double layered (NbSi2 + Nb5Si3) silicide coated Nb-1Zr-0.1C (wt.%) alloys has been studied between 800 and 1300 degrees C in static laboratory air. The single layer coated alloy shows a lower weight gain as compared to the double layer coatings at all temperatures. The formation of amorphous silica scale embedded with Nb2O5 oxide particles is observed beyond 1100 degrees C, and a superior oxidation resistance is detected between 1100 and 1300 degrees C. A kinetic equation relating the thickness of the coating layer with the various process parameters for pack siliconizing of Nb-alloy has been established. (C) 2015 Elsevier Ltd. All rights reserved.