A study of CVD growth kinetics and morphological evolution of rhenium from ReCl5

• Rhenium coatings were stably fabricated at a relatively high deposition velocity.
• The Re CVD process has been studied at direct sublimation of ReCl5.
• Kinetics of Re CVD from ReCl5 was studied.
• The effect of molybdenum substrate on Re deposition was studied and explained.
• Evolutions of coating morphology and microstructure were illustrated in a schematic.

Rhenium was fabricated on molybdenum by chemical vapor deposition (CVD) of ReCl5 in a cold-wall atmospheric pressure reactor at temperature range of 1000 to 1300 °C. To investigate the deposition mechanism, the process was carried out by direct sublimation of ReCl5 powder instead of the commonly used in-situ chlorination of solid rhenium method to supply the precursor. The effects of deposition temperature, ReCl5 partial pressure, and molybdenum substrates on deposition velocity, microstructure were investigated. The deposition was under kinetics control and fitted to a 1.5-power relation versus ReCl5 partial pressure at 1150 to 1250 °C. One reaction pathway has been proposed depending on ReCl5 partial pressure. At deposition temperature below or equal to 1100 °C, the reaction between molybdenum and ReCl5 was calculated and discussed. Evolution of coating microstructure was summarized into a schematic with four typical deposited regions, which provides a simple and efficient way to deposit certain microstructures of rhenium coatings.