Economical, Low-Thrust Chemical Rocket Engines Using Iridium-Coated, Electroformed Rhenium

A need exists for a cost effective means for fabricating high- temperature rhenium structures having good mechanical properties. A program is proposed to demonstrate the merits of fused salt deposition of rhenium on various refractory substrates using current manipulating techniques such as pulsed current and periodic current reversal to refine microstructures and improve mechanical properties. Fused salts have been successfully used to deposit other refractory metals, but rhenium deposition from such baths has been overlooked in favor of chemical vapor deposition (CVD). CVD has been the predominant technique for rhenium electrodeposition, but this method is extensive and yields a metal of inferior quality to that expected from the fused salt bath. Rhenium deposits shall be characterized from melts of various base chemistries, and responses to thermal treatment on several substrates will be examined.