Combating Erosion on Lunar Surface: The Case for Plasma Sprayed Titanium-Boron Nitride Composite Coatings

Tanaji Paul, Abhijith K. Sukumaran, Brandon Aguiar, Sohail M.A.K. Mohammed and Arvind Agarwal (Florida International University)

Abstract

Erosion from lunar dust storms are a primary cause of degradation of materials and structures that pose a significant challenge to the future of human endeavors to and habitation on the moon. The absence of understanding the mechanisms of material depletion due to high-speed impact with lunar soil at the largely varying temperatures on the moon hinders the development of protective coatings to combat lunar erosion. This study developed coatings of titanium alloy (Ti-6Al-4V) reinforced with boron nitride particles using atmospheric and vacuum plasma spray deposition techniques to protect material surfaces against lunar dust. The resistance of these coatings against erosion was evaluated in an indigenous developed “Planetary Erosion Test Rig” under cryogenic to elevated temperatures, -150 to 135 oC by showering simulated lunar regolith particles from moderate to high speeds of 22 to 110 ms-1. An integrated testing approach, consisting of measurements of mass changes in the coatings along with high-speed camera imaging of lunar regolith impact, enabled an understanding of critical material phenomena such as particle embedding and rebound at play during erosion of these coatings. A comprehensive understanding of the mechanism of erosion, as a function of temperature-dependent ductility and coefficient of restitution of regolith is established which harbors the potential for manufacturing metallic coatings with resistance against erosion in lunar environments.