Preparation and High Temperature Oxidation Properties of Micro-crystalline MGH754 ODS Alloy Coatings

摘要

A special coating technique, electro-spark deposition (ESD), was developed to produce micro-crystalline ODS MGH754 alloy coatings on a commercial ICrl8NigTi stainless steel and a cast Ni20Cr alloy substrates. The coatings have a very fine grain structure and metallurgical bonding with the substrates. The isothermal oxidation tests at 1000 ℃ in air showed that the micro-crystalline ODS alloy coatings had a much reduced oxidation rate and improved scale spallation resistance compared with the uncoated alloys. The selective oxidation of Cr was greatly promoted to form protective and continuous Cr2O3, scales on the alloy surface. Micro-crystallization and oxide dispersions have synergistic effects on the improvement of oxidation resistance. The beneficial effects were discussed based on the experimental results.