A D V A N C E D M A T E R I A L S & P R O C E S S E S | A P R I L 2 0 2 3 3 6 iTSSe TSS iTSSe TSS FEATURE NASA’s Artemis program aims to return to the moon in search of scientific discoveries and establish a habitat using in-situ resource utilization. However, the past lunar explorations presented challenges, such as thermal cycles, solar and intergalactic cosmic radiation, and severe abrasive interaction of sharp lunar regolith particles[1-4]. Dust mitigation and radiation shielding have become the most important concerns for lunar structural components and rovers which can fail abruptly without a protective solution. To counter these threats, the Plasma Forming Laboratory (PFL) at Florida International University (FIU), in collaboration with NASA, has developed a novel multifunctional coating to protect the components synergistically against abrasion, erosion, and radiation. The titanium-boron nitride composite coatings were prepared using an atmospheric plasma spray technique from engineered composite powders[5,6]. The coatings were subjected to extensive characterization and tribological study with lunar mare simulant JSC-1A, which shows tremendous improvement in the wear performance. The coatings subjected to neutron radiation shielding experiments at NASA Langley Research Center exhibited significantly improved neutron attenuation capacity compared to the substrate. The coating is selected to undergo radiation exposure on the International Space Station (ISS) as a part of MISSE-17 (Materials International Space Station Experiment). COATING DEVELOPMENT AND PROPERTY ANALYSIS The coatings were prepared at low and high vol% of hexagonal boron nitride (hBN). The composite powder was prepared using the cryo-milling technique at NASA Langley Research Center. The composite coatings were deposited on Al 6061 RADIATION SHIELDING PLASMA SPRAYED COATINGS HEAD TO INTERNATIONAL SPACE STATION FOR MISSE-17 EXPERIMENTS Titaniumboron composite coatings with superior wear performance were selected for use inmaterials experiments on the International Space Station. Abhijith Kunneparambil Sukumaran and Arvind Agarwal, FASM* Florida International University, Miami and Ti6Al4V disk substrates (Fig. 1a and b). The process parameters were optimized to achieve the highest densification in the coating and good interfacial bonding with the substrates. All coatings were deposited at a minimum thickness of 200 microns. PROMISING PRELIMINARY RESULTS Compared to the conventional titanium CM substrate, themicrohardness of the coatings was increased 3 times and 1.5 times, respectively, for low and high hBN concentrations. The significant increase in hardness and lubrication effect of boron nitride is expected to increase the coatings’ abrasive and erosive wear performance. The abrasion performance will be analyzed in atmospheric and vacuum tribometers in collaboration with NASA MSFC. The high-velocity regolith impact tests will be conducted in a custom-made erosion test rig capable of generating high particle velocities (up to 150 m/s), lunar temperature range (-196° to 150°C) and *Member of ASM International Fig. 1 — (a) Coating deposition using atmospheric plasma spraying at PFL, FIU. (b) Ti-hBN coating on a Ti6Al4V substrate. 4 Fig. 2 — MISSE experimental setup on ISS[7]. (a) (b)
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