Abhijith Sukumaran1,Cheng Zhang1,Sara Rengifo2,Sang-Hyon Chu3,Cheol Park4,Michael Renfro5,Calista Lum6,Katie Stephens7,Arvind Agarwal1
Florida International University1,NASA Marshall Space Flight Centre2,National Institute of Aerospace3,Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, VA4,Plasma Process5,University of California, Irvine6,University of California Merced7
Abhijith Sukumaran1,Cheng Zhang1,Sara Rengifo2,Sang-Hyon Chu3,Cheol Park4,Michael Renfro5,Calista Lum6,Katie Stephens7,Arvind Agarwal1
Florida International University1,NASA Marshall Space Flight Centre2,National Institute of Aerospace3,Advanced Materials and Processing Branch, NASA Langley Research Center, Hampton, VA4,Plasma Process5,University of California, Irvine6,University of California Merced7
Lightweight alloys of Aluminum (Al) and Titanium (Ti) are significant components of space systems because of their high strength-to-weight ratio. However, their poor tribological response in the presence of lunar regolith and lack of space radiation shielding ability can result in premature failures. Hexagonal Boron Nitride (hBN) reinforced titanium coatings were produced by atmospheric and vacuum plasma spray methods at low and high-volume concentrations of hBN to counter these undesirable results after powder preparation by cryo-milling. The microhardness results showed that coating hardness was 3.0 times that of conventional Ti6Al4V (335 HV) substrate in the case of low vol.% hBN (900 HV) concentration and 1.5 times in the case of high vol.% hBN coating (516 HV). Furthermore, tribological characterization by ball-on-disk tests in the presence of JSC-1A lunar regolith simulant revealed a 70% reduction of wear volume on the Ti/low vol.% hBN coatings compared to conventional material. The science of boron nitride retention and secondary phase effect in the coatings were examined using characterization techniques such as SEM, XRD, and Raman spectroscopy. Developed coatings were subjected to the simulated extreme lunar condition of neutron radiation. The coatings exhibited effective radiation shielding ability up to 31.8 % with an increase in % hBN content. Computational studies indicate that the presence of boron-based inclusions can effectively suppress generation of undesirable secondary radiations through the metal alloys against galactic cosmic rays (GCR) and solar particle events (SPE) as well. The coatings will be subjected to harsh erosive conditions on a custom-made high-velocity dust impact setup to evaluate erosion performance.