Iridium is the most promising material for ultra - high temperature structure parts oxidation - resistant coatings in aerospace field due to its high melting point, strong corrosion resistance and low oxygen permeability under high temperature. The main factors affecting the service life of the iridium coating were the microstructure and oxidation characteristics at high temperature. There were two ways to improve high temperature oxidation resistance of the coating: one was improving preparation process to enhance density of iridium coating so as to reduce coating failure caused by grain boundary diffusion, the other was preparing ceramic coating or alloying to defend iridium coating from contacting with the oxidizing environments and extend its lifetime. Aiming at the problems in the applications of iridium coating, the research progress on modification of iridium coating was reviewed. The development direction of iridium coating modification technology was prospected.
