Oxidation behaviour of micro-crystalline Ni-20Cr-Y2O3ODS alloy coatings

Ni-20Cr-Y2O3 oxide dispersion strengthened (ODS) alloy coatings were deposited on the surface of Ni-20Cr alloy by a special electro-spark technique. Two methods were used to prepare these ODS alloy coatings: (a) using M754 ODS alloy as the electrode; and (b) using M754 electrode with nano-particles of Y2O3 on the surface of substrates. The ODS coatings possess micro-crystalline structure and metallurgical bonding with the substrates. The experimental results of high-temperature oxidation in air at 1000 degrees C show that the formation of Cr2O3 scale has been promoted on these coatings with excellent scale spallation resistance. The mechanisms of the beneficial effects of these coatings were also discussed. (C) 2000 Elsevier Science B.V. All rights reserved.