Current Development Status of Rhenium Iridium Material Engines

Although rhenium iridium materials have excellent high-temperature mechanical and antioxidant properties, they were initially only used in engine throat liners due to their difficult processing and forming processes. The tungsten based/rhenium iridium coating throat liner successfully developed in the 1970s has been widely used in different types of engines. Rhenium iridium coating is coated on a tungsten substrate through a powder dip coating process. This coating can effectively reduce the hot corrosion rate of the throat lining during use and prolong its service life.

With the gradual development of material forming technology, especially the maturity of CVD and powder metallurgy technology, rhenium iridium integrated material engines have become possible. Ultramet, a subsidiary of NASA, has been committed to using metal organic compound CVD technology to prepare rhenium iridium materials since the mid-1980s. The company already has the process technology to prepare high-purity and high-density rhenium iridium materials.

At the same time, the preparation of rhenium layer by powder metallurgy and the preparation of rhenium iridium combustion chamber by electrodeposition of iridium layer have also been successful. TRW Corporation in the United States is committed to low-cost manufacturing of rhenium iridium combustion chambers. The TR-312-100 MN and TR-312-100 YN engines being developed by the company use powder metallurgy technology to prepare rhenium, and iridium coatings are prepared on the inner and outer surfaces of rhenium using electrodeposition technology. Electroplating and depositing rhodium coatings on the inner surface of the iridium layer to achieve better oxidation resistance; The outer surface of the combustion chamber is coated with hafnium oxide to achieve higher thermal radiation performance.

At present, the preparation technology of rhenium iridium combustion chamber engines has become increasingly mature, but research and development work is mainly concentrated in the United States. NASA has prepared more than 100 rhenium iridium engine nozzles, with a cumulative test time of over 200 hours. There have been no reports of successful development in other countries yet.

In recent years, relevant domestic units have also carried out research and development work on rhenium iridium nozzles, with preparation technologies including CVD, molten salt electroforming, powder metallurgy, and physical vapor deposition, all of which are currently in the development stage. Among them, the Institute of Aerospace Materials and Technology has made significant breakthroughs in its research work in this field. Rhenium based materials are prepared using powder metallurgy technology, while iridium coatings are prepared using physical vapor deposition technology. The prepared rhenium iridium material combustion chamber passed a 25000 second assessment test in October 2014, laying a solid technical foundation for the successful development of rhenium iridium material engines.