High temperature materials for magnetohydrodynamic channels

Abstract

The development of suitable materials for use in mhd generator is one of the most challenging areas. The very high temperatures (∼ 2700 K) coupled with the highly corrosive seed-laden atmosphere limit the choice of materials in contact with the plasma to just a few ceramic oxides. These materials in contact with the high temperature plasmas in mhd generator are simultaneously subjected to stresses of mechanical, thermal, chemical and electromagnetic nature. The development and suitability of the different potential electrode and insulator materials such as lanthanum chromite, zirconia-based materials, alumina, magnesia etc. are reviewed with particular reference to the mhd channel materials programme in the mhd Project at barc. The operating experience with alumina-based ceramics and other materials under mhd operating conditions is also detailed. This includes the specifications, processing, bonding of the ceramic materials, the test programme and evaluation. Also presented are some of the novel processing techniques like plasma spraying and their application in the development of mhd materials. The advantages and limitations of each of these materials and their principal mode of degradation while in service are also discussed. © 1984 Indian Academy of Sciences.