Ultrafast Pulsed Laser Deposition of cubic-Boron Nitride to Survive Extreme Environments
Abstract
Cubic-Boron Nitride (c-BN) and hexagonal Boron-Nitride (h-BN), like diamond, carbon nanotubes, and graphene, have extraordinary material properties that make them an ideal material for improving high power thermal and electrical management for linear particle accelerators, high power lasers, hypersonic aeronautical systems, long life cutting tools, and many other applications. As an example, c-BN is the second hardest known material next to diamond, is chemically inert, has a thermal conductivity four times that of copper, very high electrical insulation capabilities, a sublimation temperature of 2973 0C, and optical characteristics that make it a very useful material for min infrared optical systems. Another interesting property is its negative electron affinity. Which means any electron entering the materials will be emitted easily, making it a very useful material for use in cathodes and electron multipliers.However, due to the high sublimation temperature and hardness of c-BN, it is extremely difficult to form single crystalline, macroscopic materials. Existing c-BN and h-BN materials have a polycrystalline grain structure, with these breaks in the crystalline structure acting as weak points in the material and serve to limit its optical performance by scattering light as it travels thorough the material.The research presented here seeks to develop a new manufacturing process that has the ability to deposit thin film mono-crystalline c-BN films on a range of target materials. We will focus on a new laser-based evaporation process called Pulsed Laser Deposition (PLD), that selectively evaporates a h-BN target with a high-power laser, the resulting evaporation condenses on a substrate forming a thin h-BN film which is subsequently transformed into c-BN with the aid of high energy ion bombardment and laser melting.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 22, 2024
- Source ID
- FA86552317011
Entities
People
- William O Neill
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Cambridge